The Best Replacement Windows for 2023

As homes age, parts of their structure, including floors, cabinetry, roofing, doors, and windows, will need to be replaced. When shopping for new replacement windows, homeowners can choose from a large selection of styles, materials, brands, and other options. The purpose of this guide is to explain everything that homeowners and contractors need to know about replacement windows, including: what they are, the costs, how to buy them, installation, extending the lifespan of windows, and finally, reviews of the best replacement window companies. If you’re already knowledgeable and just want to see the best windows, here’s a short list of the top replacement window companies:

Top Window Companies

	Andersen	Pella	Milgard
Best For	Best Overall	Energy Efficiency	Low Cost
Our Rating	10/10	9.5/10	9/10
Learn More	Check Price Read Review	Check Price Read Review	Check Price Read Review

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Understanding Replacement Windows

Replacement windows are easy to understand, but there are many different types and a lot of information a buyer should learn before purchasing them.

What Are Replacement Windows?

Replacement windows are new window assemblies designed to be installed on structures using preexisting window openings. They are different from new construction windows, which are used when installing windows on a structure for the first time.

Replacement Windows vs. New Construction Windows

When shopping for new windows, there are two categories to choose from: replacement or new construction. Each type of window is best suited for a particular situation, and a homeowner should determine which is appropriate for their home before starting to shop for windows. 

As the name implies, replacement windows are most often used to replace a home’s existing windows. They are manufactured in such a way that the installer does not have to remove the exterior siding of a home, but instead uses the pre-existing window opening. Since installing replacement windows is less intrusive and does not damage the existing structure, it is less labor intensive and costly when compared to installing new construction windows.

Unlike replacement windows, new construction windows are designed to be used when the home is still in the process of being constructed—that is, windows are being installed for the very first time. New construction windows are designed to use fins, or flanges, to attach directly to the home’s framing, whereas replacement windows are smooth and do not use fins. Only once the window has been entirely installed can the home’s exterior be finished. While new construction windows themselves are usually cheaper than replacement windows, installing new construction windows is a labor intensive process and the overall cost is higher when compared to the installation of replacement windows. 

In certain circumstances, new construction windows can actually be a better option when replacing existing windows. For example, when the wall surrounding a window has rotted or deteriorated to the point that the home’s framing and studs have been damaged and need to be replaced, new construction windows are likely necessary. Another example is when the homeowner is completely replacing a wall or upgrading the home’s siding.

When to Buy Replacement Windows

Replacing old, poorly-functioning windows is a smart and easy upgrade for homeowners to consider. Some key signs that it is time to install replacement windows include:

High Energy Bills – High energy bills are often indicative of poorly functioning windows. If a room feels drafty even when the windows are closed, there could be issues with the seals and insulation that help keep a window airtight. 

Outside Noise – If a homeowner experiences a lot of external noise in the home, then the windows might need to be replaced. New double- or triple-pane replacement windows insulated with gas between the panes will absorb the sound waves and help decrease outdoor noises.

Decaying Windows – One of the most obvious signs that it is time to purchase replacement windows is when the window frame starts breaking down and decaying. This may present itself as a window frame that is soft to the touch, sagging, or rotten. Excess moisture from a leaky window could also further lead to the growth of mold and mildew.

Termite Damage – When moisture gets into a window frame, it can attract termites that will cause further structural damage—both to the window and potentially beyond. Termite damage is a common reason for replacing windows, but depending on the amount of damage, a standard replacement window might not be sufficient. In general, we recommend consulting with a top termite treatment company to assess the damage and develop prevention techniques to stop future damage before replacing the damaged windows.

Condensation – When condensation, or fog, builds up between the layers of glass, it indicates failed window seals. When this occurs, moisture is able to enter the window and will lead to a leaky window over time. Also, in this scenario, any insulating gas that was placed between the panes will escape, making the window less energy efficient than it was designed to be. 

Poor Window Operation – Windows that have become difficult to open or close because they are painted shut, swollen, rusted, or rotten, need to be replaced. Windows that do not close properly may also not be able to lock, compromising the window’s security. Ultimately, a window should operate smoothly and effortlessly and should be replaced when this is not the case.

Pros & Cons of Replacement Windows

New windows provide a wide range of benefits for both the current homeowner and the future buyer. The benefits of modern replacement windows include better home security, improved energy efficiency, reduced noise pollution, and increased resale value. Of course, new windows can make a home look a whole lot nicer, too. That said, investing in new windows can be a costly and time-consuming process. Here is a summary of the benefits and drawbacks of replacing your windows:

Benefits of New Windows

Energy Efficiency – Improved energy efficiency is one of the key benefits of replacing old or damaged windows. By guarding a home against undesirable condensation, drafts, and air leaks, energy efficient replacement windows keep the cool or warm air inside the home as desired. This helps reduce the need to continually cool or heat the home, and ultimately saves the homeowner money. Additionally, windows with energy-efficient coatings allow more natural light to enter the home (reducing the need for artificial light), while also keeping out ultraviolet rays that damage household items like fabric, carpet, wood, furniture, and artwork.

Home Security – Quality replacement windows have several features that can increase home security and prevent unwanted intruders from entering the home. While a window may not seem like it can be all that secure, there are several ways a window can be stronger and safer, while maintaining its stylistic presence. Key factors that affect the overall security of a window include its style and frame, locking system, thickness, and glazing. For example, many replacement windows come with pins and robust locking mechanisms that prevent the window from being opened from the outside. Likewise, some offer built-in contact sensors that send alerts when the window is opened. For homeowners especially concerned about security, certain types of impact-resistant glass are virtually impenetrable.

Reduced Noise Pollution – Replacement windows are available in a variety of thicknesses, including: single, double, and triple-pane. A window’s ability to block outside noise can be vastly improved by thicker glass, extra air between the glass, or laminated glass. The noise-stopping ability of a window is rated on a sound transmission class (STC) scale, with higher numbers corresponding to more noise reduction. An average single-pane window has an STC value of 27, while a double-pane window is rated marginally higher. If, however, the goal is to block as much noise as possible, then soundproof windows are a viable option, which have STC ratings ranging from 48-54 and block as much as 95% of outside noise.

Ease of Maintenance – Unlike traditional windows that need to be cleaned regularly and eventually repainted, modern windows incorporate many design features that allow for easy maintenance and cleaning. For example, new window frames are available in several materials, including vinyl, aluminum, and fiberglass, that don’t need to be repainted and require little effort to maintain. When it comes to regular cleaning, many new window styles tilt inward, which allows the outside of the window to be cleaned from inside of the house. Some new windows even feature between-the-glass shades that won’t accumulate dust or need to be cleaned at all.

Functionality – Whereas older windows tend to have issues moving up and down or sliding side to side, properly-installed replacement windows will work as expected and require little effort to operate. That said, in order to protect the value of the replacement windows and keep them working well over time, be sure to clean them regularly and perform yearly inspections. When cared for properly, new replacement windows will continue to function with ease as they age. 

Resale Value – Improved energy efficiency, home security, noise reduction, and curb appeal will all contribute to an increase in resale value. The change in value will, of course, depend on the size of the home, number of windows replaced, and quality of the replacement windows used.

Drawbacks of Replacement Windows

Outside of the time and cost involved, there are few major drawbacks to consider when upgrading windows that actually need to be replaced. Of course, there are pros and cons of different window types, materials, glass, and coatings, all of which are discussed in detail below.

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What to Look for When Buying Replacement Windows

There are several considerations for a homeowner to balance when buying new replacement windows. This section covers the most important factors to consider, including: replacement window types, frame materials, quality, and features that impact energy efficiency.

Types of Replacement Windows

It is natural to start the process of buying replacement windows by considering what the new windows might look like. There are many different styles to choose from. While some have a specific look or add character to a house, others offer unique functions. Here are the most common styles of replacement windows. 

1. Double-Hung Windows

Double-hung windows look classic. They have operable lower and upper sashes that allows air to enter through the top and bottom of the window. Often, the sashes tilt inward; sometimes, however, the sashes slide vertically along a track instead. This is one of the most popular styles of window, and it is available in a variety of styles, materials, colors, and cladding. One negative aspect of this window style is that the sashes can impede the view through the window. 

2. Single-Hung Windows

Single-hung windows have a similar appearance to double-hung windows, but differ in that they only offer a single operable sash. The lower sash may tilt or slide vertically along a channel. Single hung windows tend to be more affordable than similar double hung windows. As with double-hung windows, the construction of the window can impede views to outside.

3. Sliding/Gliding Windows

Sliding windows are different from double and single-hung windows in that they move horizontally along the track, rather than vertically. They have one or more panels that move and allow for half of the window to be open. Usually, only a single panel slides while the other remains fixed. Sliding windows can have the same view-obstruction problem that hung windows have. Another downside to this style of window is that dirt and debris tend to gather along the bottom track, which can make the window difficult to open if it is not regularly cleaned and maintained. This is one of the most affordable styles of windows.

4. Casement Windows

Casement windows are hinged on one side with the ability to pivot outward on the other side. They allow for a great deal of ventilation and are easy to open. Most window manufacturers offer these, as they are an extremely popular type of window. Since they open outward, homeowners should consider carefully where they choose to install these windows. Installing these windows over patios or walkways could create an obstruction when the window is open.

5. Awning Windows

Awning windows are similar to casement windows, but they are hinged at the top (instead of the side) and open from the bottom. Awning windows are designed to prevent rain from entering a room when the window is open.

6. Projection Windows

Projection windows, such as bow (left) or bay (right) windows, project outward from the house. The design features multiple fixed panels that complete the entire window and are positioned at various angles. This style allows an enormous amount of light to pass through, illuminating rooms in the daylight hours. These windows tend to be more expensive and are more difficult to install.

Other Window Styles

There are several other types of windows that are less common, but also useful to know about:

• Picture Windows – Picture windows are non-operable and are designed to provide large unobstructed views from inside the home while allowing a lot of natural light to enter. The downside of these windows is the lack of ventilation they provide since they do not open.
• Hopper Windows – Hopper windows are similar to awning windows, but instead, are hinged at the bottom and open from the top. Hopper windows are normally placed low on an exterior wall and are designed to provide airflow for a basement.
• Accent Windows – Accent windows also typically do not open and are similarly designed to offer aesthetic appeal instead of providing ventilation. They are smaller than picture windows and come in many shapes and styles. 
• Glass Block Windows – Glass block windows are made from individual glass blocks and held together by mortar. The thick glass provides privacy, while still allowing light to enter the home. These windows are generally fixed.
• Skylights – Skylights are mounted in the ceiling and can be fixed or operable. They allow a large amount of natural light to enter the home and can improve air flow. 
• Storm Windows – Storm windows are temporary or permanent fixtures that are mounted directly to the inside or outside of the main windows of a home. They can be made of plastic or glass panels and create a layer of insulation that increases the energy efficiency of single-pane windows.

Replacement Window Frame Materials

Window frames come in a variety of materials which influence the look and durability of the window. The type of material used also impacts energy efficiency and required maintenance. Some window frame materials are better suited for particular climates, as high temperatures can affect the long term durability of some frames. Homeowners and contractors should be mindful of the different materials that comprise a window, taking special notice of the quality and suitability of the materials for the project.

1. Vinyl

Vinyl windows are an affordable replacement window option made from polyvinyl chloride (PVC). They are rigid and possess hollow chambers inside that make them energy efficient by helping them resist both heat transfer and condensation. Vinyl windows need little maintenance as they do not require any kind of painting or finishing, and they do not fade, rot, chip, or peel. Most companies will offer lifetime warranties on their vinyl options. The material does, however, limit the choice of colors to shades of white, black, gray, and brown. Also, vinyl windows can begin to warp when exposed to high temperatures and may expand and contract with temperature fluctuations. For these reasons, they may be better-suited for milder climates.

2. Fiberglass

Fiberglass windows are a bit pricier, but when compared to vinyl windows, they are even more energy efficient and durable. Fiberglass windows are resistant to temperature changes that cause other materials to expand and contract, which means that hardly any air leaks around the frame. Known for their strength, fiberglass is as low maintenance as vinyl.

3. Wood

Although quite expensive, wood is an elegant replacement window option. Wood does not conduct as much heat as other materials do and does not allow for much condensation to build up. Wood does require substantial upkeep in order to prevent warping, rotting, and chipping, however. Additionally, for residents that live in an area with termites, working with a termite treatment company to develop a reliable prevention strategy is recommended. Still, with proper care and refinishing as needed, wood can be an attractive choice for the right house.

4. Aluminum

Aluminum is an inexpensive option for replacement windows. Aluminum windows are long-lasting because they resist corrosion, and give the window an industrial appearance. They are known to have issues with efficiency since metal does conduct heat; however, this issue can be resolved by selecting an aluminum window that has thermal breaks. 

5. Composite

Composite windows are a blend of materials that consists of resin and fiberglass. The material is strong and lightweight and requires the same level of maintenance (or lack thereof) as do vinyl replacement windows. While composite windows share similar features of vinyl and fiberglass windows, they actually mimic the appearance of wood windows, and they are priced in between vinyl and wood options.

6. Clad

Clad windows exist for individuals who want the durability that vinyl, fiberglass, and aluminum windows offer, combined with the artistry of wood. These are windows that have wood on the interior of the home, and one of the aforementioned materials on the exterior of the home. They require less maintenance since the wood only exists on half of the window, and they offer the same level of protection as vinyl or fiberglass options.

Summary of Window Frame Materials

	Vinyl	Wood	Aluminum	Fiberglass
Low maintenance	✓		✓	✓
Resistant to decay (rotting, chipping, fading, cracking, peeling)	✓		✓	✓
Insulating	✓	✓		✓
Color/finish options		✓	✓	✓
Durable		✓	✓	✓
Will not bend or warp				✓
Resists temperature expansion/contraction				✓

*Composite and clad frame materials are not included in the table because their performance depends significantly on the blend of materials used.

Replacement Window Quality

In addition to window styles and frame materials, the overall quality of a replacement window’s construction should impact a homeowner’s decision to purchase it. The performance of a replacement window, or lack thereof, can have a direct impact on the cost of heating and cooling a home as well as the durability of the window over time. Here are some tips to help determine whether a window is a quality product, or cheaply made: 

1. Hardware

The hardware of a window consists of all of the components used to open and close a window. Quality hardware is made from solid steel that is cut on laser machines, while cheap hardware is made from stamped metal parts or folded metal sheets. While other materials can rust over time, parts made from sturdy materials, like stainless steel, will allow the window unit to operate smoothly. Also, windows that have a stable transition from the locked and unlocked position are an indication of quality. Some windows are designed to hide and protect the gear mechanisms from dust, which ultimately improves the longevity of the parts. Finally, handles and locks made from plastic do not offer the same level of quality as those made from nickel and other metals. 

2. Multi-Chamber

When shopping for replacement windows, it is helpful to look at cutouts that allow you to see the internal structure of the window. Look for a window that is constructed from thick walls and multiple chambers or pockets. The chambers are designed to improve the window’s structural performance by helping to prevent warping as well as enhancing sound insulation. 

3. Reinforcement

Reinforcement, using metal or wood, is used to provide structural rigidity to a window. Reinforcing members can be included inside the window, in various window components, or in-between window units. Reinforcement is often necessary for very large window units, but can also indicate that a smaller window unit may have been made poorly, as small windows should not need reinforcement. Wood reinforcements may also indicate poor construction as they compromise the energy efficiency of the window. Similarly, metal reinforcements conduct heat, which also inhibits the energy efficiency of the window. Look for a window that is constructed from thick walls and does not require the use of reinforcements (except for with large applications, where the use of reinforcements is unavoidable). A quality window has a high degree of rigidity without the need to add additional reinforcement.

4. Compression Seal

Compression seals are used to protect against drafts and keep rain and other elements from entering the home. They are placed between the sashes and frames of a window. For sliding windows, weatherstripping is used, and for casement or awning windows, bulb seals are used. High-quality windows will feature three seals, while low-quality windows might only have one or two seals. Quality seals are made from Santoprene rubber, which acts as an effective insulator. It is a durable material and will keep a window properly sealed for many years. On the other hand, cheap seals are made from PVC, which breaks easily and will lose its sealing power after only a couple of years.

Energy Efficiency 

For many homeowners, energy efficiency is the most popular selling point for replacement windows. According to a report by Dodge Data & Analytics, 81% of builders and remodelers consider high-efficiency windows important. The National Association of Home Builders (NAHB) listed home energy efficiency as the second most likely quality to influence a purchase decision behind community safety. Fortunately, there are clear indicators of energy efficiency when shopping for windows: the ENERGY STAR label, NFRC label, low-E coatings, and insulated glass.

1. ENERGY STAR Label

The first thing to look for when browsing energy efficient replacement window options is the ENERGY STAR label. Windows with an ENERGY STAR label are independently tested and certified by the National Fenestration Rating Council (NFRC), and have been issued ratings that meet EPA standards for energy efficiency. Specifically, the ENERGY STAR label is reserved for windows with sufficient U-factor and solar heat gain coefficient (SHGC) ratings, which measure a window’s rate of heat transfer and its overall ability to block heat from the sun, respectively. As different climates require more or less insulation from the sun, performance criteria varies from region to region. 

2. NFRC Label

National Fenestration Rating Council (NFRC) testing looks at more than a window’s U-factor and SHGC. In addition to measures of heat transfer and sun-blocking, the NFRC tests visible transmittance, air leakage, and condensation resistance. An NFRC label will not, on its own, indicate a good or bad window. While the ENERGY STAR label certifies those windows that perform well in the two main categories of NFRC testing, the NFRC label displays the plain results of the five categories in which each window is tested. See the table below for help interpreting the NFRC label when comparing multiple energy efficient replacement window options.

3. Low-E Coatings

Low emissivity, or low-E coatings are thin and transparent coatings that increase the energy efficiency of replacement window glass by reflecting heat while still allowing light to enter. In warm climates, the coating is applied to the outside glass in order to reflect the sun’s rays, whereas in cold climates, the coating is applied to the inside glass in order to keep heat in. The effectiveness of low-E coatings and their ability to regulate the temperature inside a home are shown on the NFRC label, so pay close attention to the values when comparing multiple products. 

4. Insulated Glass

Insulated glass makes a home more energy efficient through the use of multiple panes and an insulating medium. Double-glazed refers to a window that uses two glass panes, while triple-glazed refers to a window that uses three glass panes. The panes are separated along their edges by foam or metal spacers, and the space in-between is filled with an insulating medium, such as air, argon, or krypton gas, that works to slow the transfer of heat through the window. 

In summary, energy efficiency is a desirable characteristic for most homeowners when looking to purchase new replacement windows. It is important to note the ENERGY STAR label and compare the NFRC ratings of many products. Look for other indications of an energy efficient replacement window, including low-E coatings as well as insulated glass, in order to find the product that is best suited to a home’s needs. Lastly, remember that there are additional fixtures that can be added to replacement windows to further reduce energy usage in the home. To learn more about additional ways to improve the energy efficiency of replacement windows, see the section on improving energy efficiency below. 

Installation

Another important thing to look for, as a buyer, is whether the company that sells or manufactures the window offers installation. Several companies that offer replacement windows also have professionals available to install the new windows. Even for homeowners who are capable of performing the replacement on their own, paying the company who produced the window has benefits. Aside from saving time and effort, professional installation usually includes warranties that protect the homeowner from the cost of damages that result in faulty installation. 

Third-party contractors that aren’t associated with the window manufacturer will also be capable of installing the window, and they may even offer a warranty too. However, the benefit of using the manufacturer’s network to install windows keeps the accountability solely on them should anything go wrong with the window, whether due to installation issues or faulty manufacturing.

Warranties

Warranties vary in their coverage and might only be valid for a certain amount of time. How a warranty is defined can also vary across manufacturers. For example, the term lifetime can mean different things depending on the company, but most commonly refers to either the life of the owner or the expected lifespan of the window. With that in mind, here are the most common types of available warranties:

• Limited Lifetime Warranties – A limited lifetime warranty is a common warranty offered by replacement window companies that generally covers performance and aesthetic defects. It is called a limited warranty because it only covers certain parts of the window. It is possible to have a limited lifetime warranty that lasts only 3-5 years.
• Lifetime Warranties – A lifetime warranty is a more inclusive warranty that covers all replacement parts of a window should something break or go wrong. Remember that the term lifetime does not always mean the same thing. A lifetime warranty might be valid for only a few years but could also last upwards of 15-20 years or longer. Some warranties can be transferred to a new owner should the original homeowner decide to move.
• Prorated Warranties – A prorated warranty of either type means that the homeowner will be required to pay a percentage of the replacement parts. The older the window is, the more it will cost to have it repaired.

The coverage that a warranty will include also differs between manufacturers. Be mindful of any exclusions the warranty may note. Here’s what to look for with regard to coverage: 

• Materials – Replacement window materials are usually guaranteed to last a specified amount of time without breaking down. If, for some reason, the materials become damaged within the time period, replacement should be covered under warranty.
• Defects – Small defects such as inconsistent color characteristics are commonly covered by warranties.
• Hardware – Hardware that is broken or not functioning properly is usually covered under warranty.
• Energy Efficient Glass Options – Argon or krypton gasses that are used as insulating mediums inside of glass panes are intended to last many years and will leak at a rate of less than 1% per year if functioning properly. If the gas disappears at a quicker rate, the warranty should cover this issue. 
• Obstruction of Vision – Occasionally a problem develops where dust or moisture inside of the glass panes creates a film that results in obstructed vision. The warranty will usually cover such an issue.
• Installation – Most warranties are often voided when a homeowner installs replacement windows. However, contractor error can be covered under a warranty when professional installation is chosen. Independent contractors may also offer their own warranties.
• Custom Options – Defects present in custom glass options, such as designs, etchings, or grids, should be covered under warranty.
• Glass Breakage – Some warranties cover the accidental breakage of glass.
• Exclusions – While some coverage is better than no coverage, replacement window warranties can exclude a number of issues that might go wrong on a window. Be sure to read through all of the loopholes and exclusions included in a manufacturer’s warranty when shopping for replacement windows that include a warranty. 

Company Reputation 

The final major factor to consider (apart from cost) when shopping for replacement windows is the company’s reputation. This guide includes a section with exhaustive replacement window reviews that compare each company’s product offerings, costs, available styles, installation options, warranties, and more. All of the companies listed in this guide score well across these categories and have received strong reviews from their customers. 

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Replacement Window Costs

Replacement windows vary significantly in price depending on the type of material, style of window, method of installation, and other factors. 

How Much Do Replacement Windows Cost?

On average, replacement windows cost about $650 each, but can be as low as $150 and as high as $2,000 or more for custom or specialty windows. Labor costs add an additional $100-$300 per window. Therefore, replacing all of the windows on a standard three bedroom home could cost between $3,000-$10,000, depending on the chosen specifications.

Factors That Affect the Cost

The cost of replacement windows varies drastically depending on a number of conditions. Some of the most influential factors that affect the cost include the material, style, and installation. Other factors that have an impact include the location in the house, window size, and energy efficiency rating. Fortunately, government incentives and local rebates can help reduce the cost associated with the purchase of replacement windows. 

1. Material

In addition to influencing the look, performance, durability, and required maintenance of replacement windows, material is one of the main factors that determines the cost. Aluminum windows are generally the cheapest, while wood or materials that give a wood-like appearance, such as fiberglass or composite, tend to be much more expensive. The table below summarizes the range of costs for popular window frame materials. Remember that labor is an added expense to the cost of each window, and averages about $100-$300 per window.

Window Material	Price Range (each)
Vinyl	$100-$800
Fiberglass	$300-$1,500
Composite	$250-$1,300
Wood	$200-$1,250
Aluminum	$100-$500

2. Style

Another key decision when selecting replacement windows is determining which window style or styles to use throughout a home. Choose one style, or a combination of styles, that fits well with the home’s overall design scheme. Keep in mind that window styles requiring a high level of skill to install can increase the installation time and labor costs. The table below summarizes the range of costs for popular replacement window styles (not including labor).

Window Style	Price Range (each)
Double-Hung	$100-$700
Single-Hung	$100-$500
Sliding	$150-$750
Projection (Bay/Bow)	$1,000-$5,000
Picture/Fixed	$250-$1,250
Casement	$200-$1,500
Awning	$350-$800

3. Installation Method: Contractor vs. Do-It-Yourself

After picking out the right replacement windows, a homeowner must decide on a method of installation: hire a professional contractor or DIY (do-it-yourself). 

When hiring a contractor, labor costs add about $100-$300 per window. The cost of labor is greatly influenced by the window size, style, complexity of the installation, accessibility to the installation site, and overall time required to install the replacement. In addition, labor costs more in expensive urban areas than in smaller, less expensive locations. One way to reduce the cost of labor is to replace many windows at once. With a higher volume job, the overhead costs associated with the contractor’s travel time, setup, cleanup, and disposal fees remain about the same, thus lowering the cost per window.

While most homeowners do not have the necessary skills required to install replacement windows, some will want to tackle the project themselves. Those that do have the skill set should read installation guides to help simplify the job. Set a realistic schedule to read through the guides and perform the work before tackling replacement window installation. 

4. Availability of Rebates

The cost of purchasing and installing new replacement windows adds up quickly, especially when replacing all of the windows in a home at once. However, rebates offered by the government as well as local utility companies do exist to help lower the cost associated with purchasing replacement windows. 

To see if there are energy efficient incentives in a particular state, first check the Database of State Incentives for Renewables and Efficiency (DSIRE). Additional local rebates exclusively offered for ENERGY STAR certified products can be found here. Rebates can ultimately save a homeowner hundreds or even thousands of dollars when buying new replacement windows, so be sure to look into these incentives before making a purchase. 

Other Factors That Affect Cost

In addition to the material, style, and method of installation, several other factors influence the cost of replacement windows. Depending on the location or room in the house where replacement windows are necessary, the price of labor can vary. For instance, installing windows on a second-story floor is more expensive than installing windows on a ground-level floor. 

Likewise, larger windows will be more expensive than smaller windows due to increased material costs and longer installation times. Windows that are double- or triple-glazed and contain insulating gasses are also more expensive than single pane windows with less insulation. Finally, any unforeseen structural deficiencies that make the job more time-consuming are going to increase the overall cost of replacement windows.

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Best Replacement Window Reviews

Below is a list of the best replacement window companies with reviews of their product offerings, costs, available styles, installation options, warranties, and more. Each of these companies rates highly on all of these factors.

Andersen (Best Windows Overall)

Overview

Andersen is the most searched for replacement window company. They have extensive style and material options with different levels of energy efficiency, security, and quality to meet the different needs of all homeowners.

Selection

Andersen, like other window companies, offers their replacement window options through different “series” or collections of windows that are grouped by their design and purpose. Here is a summary of the different series of windows offered by Andersen, listed from most to least expensive:

• A-Series (Wood and Vinyl) – The A-Series is a collection of very high-quality windows by Andersen. Both the A- and E-Series windows are a part of Andersen’s Architectural Collection, which are the best-performing and most energy-efficient windows that Andersen makes. The A-Series is defined by a wood interior and a low-maintenance vinyl exterior. Buyers have 11 vinyl color options for the exterior, a choice of six different types of wood, and different glass options with varying energy efficiency. The styles available are awning, casement, double-hung, picture, and custom designs.
• E-Series (Wood and Aluminum) – The E-Series is Andersen’s custom design option for buyers with special situations and needs. It is a premium option that costs more, but is a great choice for homeowners with unique design taste. While the design is highly-customizable, the windows feature a wood interior and aluminum exterior with over 50 color options. As always, Andersen allows a choice of glass. Since these windows are entirely custom, buyers can get this series in almost any style, including awning, push-out awning, casement, french casement, double-hung, sliding, picture, bays or bows, and other custom designs.
• 400 Series (Wood and Vinyl) – The 400 Series is Andersen’s most popular series of replacement windows. It is similar to the 200 Series of new construction windows, but is a step up in terms of quality. The 400 Series is Andersen’s best blend of performance and style. These windows have a vinyl exterior with both wood and vinyl on the interior. Buyers of this series will have more vinyl color options and three different wood species to choose from. Buyers still choose the glass used. The styles available in this series of windows are awning, casement, double-hung, sliding, picture, bays or bows, and custom designs.
• 200 Series (Wood and Vinyl) – The 200 Series is a streamlined collection of replacement window options from Andersen, which allows Andersen to offer quality options at a better price point for many consumers. Andersen only offers the most popular sizes and styles for the 200 Series, but the 200 Series does have appealing wood materials with a vinyl exterior for weather protection and durability. The 200 Series provides a choice of glass but has only two interior and two exterior finish options. Styles available include double-hung, sliding, and picture windows, along with select gliding and swinging patio door options.
• 100 Series (Composite) – The 100 Series of replacement windows is Andersen’s budget-friendly series. These windows are built from a material called Fibrex, which is specific to Andersen products, and is a composite material made from 40% wood and 60% thermoplastic. It is twice as strong as vinyl and can withstand temperatures of 150 °F. 100 Series windows are available in six different colors, including black, brown, gray, and white, and buyers have a choice of glass. Available styles include: awning, casement, single-hung, sliding, picture, and custom designs. This is Andersen’s lowest cost option.

Quality

Andersen offers premium, high-quality replacement windows, but also has low-cost options that are still great quality. Buyers looking to purchase the highest-quality windows should explore Andersen’s A-Series and 400 Series windows, which are the most energy efficient, durable, and long-lasting windows in Andersen’s collection.

Energy Efficiency

Energy efficiency is a major part of Andersen’s brand, and they offer a variety of glass options with every window they make. Once a buyer chooses the material and style that best suits their needs, they can choose between a number of glass options that Andersen offers, which are suited for different environments and needs. For example, Andersen offers Sun Glass, which has a subtle tint to block out sunlight, for warmer southern climates while its PassiveSun and Triple-Pane options better handle temperatures in cooler Northern climates. Additionally, Andersen has a HeatLock coating that can be added to most glass options for additional efficiency.

Material

Andersen makes windows in any of the popularly used materials: wood, vinyl, composite, aluminum, and fiberglass. Andersen’s different series of windows are built from different materials. Here is a summary of where Andersen makes use of each material:

• Wood – Wood is used in Andersen’s A-Series, E-Series, 400 Series, and 200 Series, which are all high-quality collections of windows.
• Vinyl – Vinyl is used as an exterior protective cladding to the wood used in Andersen’s 400 Series and 200 Series of windows.
• Composite – Andersen’s composite material, which they claim is twice as strong as vinyl, is made from reclaimed wood fiber and thermoplastic polymer that is fused together. This blend is unique to Andersen and is used in their A-Series and 100 Series windows.
• Aluminum – Andersen uses aluminum as cladding on their E-Series of windows.
• Fiberglass – Andersen uses fiberglass as a tough, weather-resistant exterior cladding to minimize maintenance. Fiberglass is only a component of Andersen’s A-Series windows.

Styles

Andersen makes windows of every popular style, meaning buyers can choose between single-hung, double-hung, casement, awning, projection, sliding, picture, or custom specialty windows. Not every style is available in every series, however, so buyers should check to be sure that their desired design will work with their preferred series. Andersen also allows buyers to design fully custom windows to be built and delivered by Andersen.

Upgrades

Andersen provides a number of options and accessories for their windows, including several glass options, artistic glass designs, unique grille/muntin styles, exterior trim additions, insect screens, blinds, shades, and locks for their windows. They also offer smart home solutions and security options for their replacement windows.

Company Reputation

Andersen is one of the most popular window and door companies in part due to their commitment to great service for their customers. Currently, Andersen has an A+ rating with the Better Business Bureau and has addressed every customer complaint submitted there. Reviews from around the web generally show outstanding reviews from their customers, and the experts at J.D. Power have found similarly high levels of customer satisfaction. Renewal by Andersen took the top spot in J.D. Power’s most recent U.S. Windows and Patio Doors Satisfaction Survey, with an 877 out of 1,000, while Andersen came in third with a score of 854.

Cost

Andersen windows start at approximately $300 per window and can cost significantly more for highly-customized and high-quality options. Compared to their biggest competitor, Pella, Andersen windows are slightly more affordable and provide a similar level of quality. However, given the variety of options available through Andersen, costs may go higher, particularly for series like the A Series, E Series, and 400 Series. In contrast, buyers who are looking to save should target more affordable Andersen options like the 100 Series or 200 Series.

Installation

Renewal by Andersen is a division of Andersen that provides full-service installation to Andersen customers. Buyers can get warranty-backed installation this way or refer to Andersen’s network of retailers nationwide who also provide installation. Andersen provides a great tool on their website for finding retailers and installers of their windows. This tool even lets buyers search retailers by the specific collections and features they offer. For homeowners who want to install Andersen windows themselves or use a different local contractor, Andersen also provides instructions for installation on their website and with the windows at the time of purchase.

Warranties

Andersen offers a robust warranty for their windows, which covers failure caused by faulty craftsmanship and failure of window materials. Specifically, their warranty covers glass, wood components, wood composite components, hardware, weatherstripping, blinds, insect screens, and exterior painted or anodized aluminum surfaces. Andersen warranties are also transferable in the event that you sell your home. And if Andersen or one of their retailers installs the windows, they offer a separate warranty to cover failures caused by improper installation. You can conveniently find sample warranty documents on Andersen’s website for additional details and information.

Recommendation

Andersen has an extensive collection of windows with many options and an extremely favorable customer reputation. They have a large network of retailers and installers, and provide strong warranties for their products. Their windows are also available at a variety of price points suitable for any homeowner. For all of these reasons, we rate Andersen as the company with the Best Overall Replacement Windows.

Pella (Best for Energy Efficiency)

Overview

Pella is one of the most trusted names in windows and doors, and has one of the most extensive selections of replacement windows.

Selection

Pella offers a variety of styles and materials, and they offer different product lines for different homeowner needs. Here is a summary of Pella’s different replacement window product lines and how they differ from one another. They are ordered from most to least expensive.

• Pella Reserve – This Pella Reserve series is actually Pella’s option for people who want extreme customization. A homeowner or contractor can bring their custom window drawings or designs to Pella and have them designed and manufactured for installation. This will cost more than Pella’s other options but also allows buyers to purchase exactly what they want for their home.
• Architect Series (Wood) – Pella’s Architect Series is a collection of wood windows that use high-quality materials and provide enhanced security and energy efficiency. The series has eleven exterior finishes to choose from, along with four interior paint options, nine interior stains, and a variety of hardware and grille options. These wood windows are available in multiple styles, including casement, single-hung, double-hung, awning, and bay or bow windows.
• Pella Lifestyle Series (Wood) – This series of windows also uses wood, but is more affordable. The Lifestyle Series includes four paint and four stain choices for the interior and twelve exterior options. The series includes multiple styles, including casement, double-hung, awning, and picture windows.
• Pella Impervia (Fiberglass) – Pella’s Impervia Series emphasizes durability and energy efficiency. They are strong fiberglass windows built from Pella’s patented, five-layer fiberglass material, making the windows extremely secure and resistant to extreme heat and cold. The finish options are fairly limited but still stylish, with a total of seven frame choices including a mixture of single and dual-color choices. The Impervia Series comes in several styles, including sliding, double-hung, single-hung, casement, awning, and picture windows.
• Pella 250 Series (Vinyl) – The 250 Series offers an excellent combination of durability and energy efficiency at a good price point. Though not as good as some other Pella lines for quality, security, or noise reduction, the 250 Series is a strong product for most homeowners and contractors. This series has a total of six color options, with three single-color frames and three dual-color options. The 250 Series is offered in casement, sliding, single-hung, double-hung, and picture window styles.
• Encompass by Pella (Vinyl) – Encompass is Pella’s collection of windows for buyers on a budget. These are built with high-quality fade-resistant vinyl. Despite being offered at a low cost, these windows are still a strong energy-saving option, meeting or exceeding ENERGY STAR guidelines in all 50 states. The Encompass Series can be purchased in three frame colors with double-hung, single-hung, or sliding window styles.
• Pella Hurricane Shield Series (Vinyl) – This series was built to withstand extreme weather and coastal conditions. In addition to incredible durability, these windows also have noise, UV ray, and security protection. With a focus on durability, the Hurricane Shield aesthetic options are more limited, with two solid frame options and one dual-color frame. The Hurricane Shield Series comes in awning, casement, single-hung, and sliding window forms.
• Pella Defender Series (Vinyl) – Pella’s Defender Series is another highly-durable collection of replacement windows with a greater focus on impact resistance and energy efficiency. The durable construction of these windows blocks 99.7% of all UV rays, makes them more secure from intruders, and also reduces noise pollution, thereby offering a variety of protections to your home. Frame color options are limited, with just two solid and one dual-color selection available. The styles available are also constrained, with the Pella Defender Series available only in double-hung, single-hung, or sliding styles.

Quality

Pella makes some of the highest quality vinyl, wood, and fiberglass windows on the market, which is why they are one of the most widely-known brands in replacement windows. Their high-quality windows means that buyers won’t have to replace them any time soon, and that they will be shielded from extreme weather, burglary, and unwanted noise pollution.

Energy Efficiency

Pella offers a number of window options that are very energy efficient and lets the buyer select the best type of glass for their local environment and needs. Pella’s Impervia, Defender, and Hurricane Shield Series are all focused on energy efficiency and durability. Even Pella’s low-cost options, like the Encompass Series, meet or exceed the minimum ENERGY STAR energy efficiency standards in every state. And each type of window can be enhanced with more energy efficient glass.

Material

Pella offers wood, fiberglass, vinyl, and aluminum-clad wood windows. Each Pella series is made from a different material, but every window style is represented in at least one of those material categories. The only exceptions are bow or bay windows, which Pella only offers in wood for structural integrity.

Styles

Pella’s replacement window selection includes several options from each different style of window that they make. They offer casement, double-hung, single-hung, awning, projection (bay and bow), sliding, and picture window designs. Not every series has all of these styles available, so you should consider which styles are available in which materials before making a decision. Additionally, if you have unique or specialized window designs, the Pella Reserve Series provides extensive options for customization.

Upgrades

Pella offers a number of upgrade options for their windows, including impact-resistant glass, improved energy efficiency, between-the-glass blinds, screens, and integrated security sensors. Pella’s existing series include a variety of these options, but their interactive Pella Design Works program allows users to design their ideal windows with the help of a Pella professional. Through this process, buyers can add and customize any number of these upgrades to their windows.

Company Reputation

Pella has a strong reputation with its customers, earning an A+ with the Better Business Bureau. While Pella has received a number of complaints from customers with the BBB, they have taken action to resolve every issue and negative review, which shows their dedication to customer satisfaction. J.D. Power also finds respectable satisfaction levels for Pella-manufactured windows, giving Pella an 866 out of 1,000 in its most recent U.S. Windows and Patio Doors Satisfaction Survey, an impressive 12 points above the industry average.

Cost

While Pella offers very high-quality windows, they also offer several series of windows with narrower options or more affordable materials in order to provide a lower cost option for people on a budget. Pella’s windows are durable, secure, and energy efficient across the board, but options like the 250 Series or Encompass by Pella may be best for buyers willing to make some slight tradeoffs to help save money.

With Pella’s extensive variety of options, the actual cost will be very specifically tied to the series, styles, and materials the buyer chooses. In general, however, windows start around $300 a piece and can cost over $2,000 for highly customized options.

Warranties

Pella offers a number of warranties on purchases of their windows. Each window material uses a different warranty because of the different ways different materials fail over time, but buyers of any Pella window will be protected by their limited lifetime warranty.

For replacement customers, the Pella Care Guarantee is also available as long as the Pella products are purchased and installed through a local Pella showroom. In addition to the typical product warranty, this limited warranty provides protection from faulty or incorrect installation of the windows.

Installation

Buyers always have the option to install their replacement windows on their own. However, Pella has professionals throughout the United States who can install their windows. One of the biggest benefits of commissioning a Pella pro to install the windows is the Installation Warranty that Pella provides, which protects owners against damages that result from faulty installation of the windows.

Recommendation

Pella is a leader in replacement windows and maintains a strong emphasis on energy efficiency, with consistently high ratings from ENERGY STAR. With an extensive selection of energy efficient options, we rate Pella’s products the Best Replacement Windows for Energy Efficiency.

Milgard (Best Windows for a Budget)

Overview

Milgard is a very popular window and door brand with over 50 years of experience providing quality products. They have a variety of options in terms of materials, affordability, and efficiency. One important note for potential Milgard customers is that they no longer offer wood windows, which has helped Milgard keep their products affordable but may be a dealbreaker for some buyers. However, Milgard still offers a high-quality selection for buyers looking for alternatives to wood.

Selection

Like the other replacement window companies in this guide, Milgard segments their window selection into different collections, or series. Here is a summary of each series Milgard offers:

• V400 Tuscany Series (Vinyl) – Milgard’s Tuscany Series is a collection of top-of-the-line premium vinyl windows that provide a traditional look that resembles wood-framed windows. Buyers have the choice of nine different color options. These windows also include Milgard’s SmartTouch hardware, which is a locking mechanism that can be locked or unlocked with one hand. The Tuscany Series offers windows in many styles, including single-hung, double-hung, slider, casement, awning, picture, radius, and projection windows. The Tuscany Series is one of Milgard’s more expensive options.
• V300 Trinsic Series (Vinyl) – The Trinsic series of Milgard windows is similar to the Tuscany series in construction, but offers a more contemporary aesthetic with narrow frame profiles. Like the Tuscany Series, Trinsic Series windows are built from Milgard’s signature vinyl formula, make use of SmartTouch locks, and are available in nine different colors. These are available in single-hung, slider, double-slider, casement, awning, picture, and radius styles. The pricing on the Trinsic Series is similar to windows in the Tuscany Series.
• V250 Style Line Series (Vinyl) – The Style Line Series is Milgard’s most affordable collection of vinyl windows. These windows use Milgard’s signature vinyl formula, but at a lower price point than the Trinsic and Tuscany collections, thanks in part to the slim frame style. The Style Line Series comes in two standard colors, white and tan, along with seven other premium exterior frame options. The Style Line Series is available in single-hung, slider, casement, awning, picture, and radius styles.
• C650 Ultra Series (Fiberglass) – The Ultra Series of windows is made from fiberglass and offers a contemporary design. One of the primary selling points for the Ultra Series is its durable, energy efficient construction, as the fiberglass material stands up well to heat, cold, and other stress. The Ultra Series has four exterior color options, each of which can be color-matched on the interior or paired with a white interior. The window hardware also has five color options: white, clay, dark bronze, brushed chrome, or black. For window styles, the Ultra Series is offered in single-hung, slider, casement, awning, picture, radius, and projection styles. The Ultra Series is on the more expensive side for Milgard, with the cost comparable to the Tuscany and Trinsic Series.
• A250 Thermally Improved Aluminum Series (Aluminum) – The Thermally Improved Aluminum Series, as the name suggests, is built from aluminum to provide strength and durability, with thermal barriers for improved energy efficiency and weather resistance. The series’ narrow frames are good for conveying a modern aesthetic. The Thermally Improved Aluminum Series is available in single-hung, slider, casement, awning, picture, and radius styles.
• A150 Standard Aluminum Series (Aluminum) – The Standard Aluminum Series from Milgard offers all the same durability and the pleasing modern aesthetics of the Thermally Improved Aluminum line, but at a lower price point and without the same level of energy efficiency. The Standard Aluminum Series is available in single-hung, slider, casement, awning, picture, and projection styles.

Quality

Milgard makes high quality vinyl, fiberglass, and aluminum windows, and in its higher-priced lines, additional enhancements are available. The main knock on Milgard in terms of quality is that they do not offer wood windows, which tend to be the highest quality windows available. However, customers who aren’t interested in wood windows can find extremely high-quality windows from Milgard comparable to the vinyl, fiberglass, and aluminum options available through other manufacturers.

Energy Efficiency

Milgard is an ENERGY STAR partner, meaning they make windows that meet the ENERGY STAR standards. Milgard windows can be upgraded with a number of features that add to their energy efficiency, including double- and triple-pane windows, Low-E coatings, spacers for double-pane windows, and Argon or Krypton gas-filled spacers.

Material

As mentioned above, Milgard no longer offers wood or wood clad windows, but they do manufacture windows made of vinyl, fiberglass, and aluminum. The exclusion of wood in their assemblies serves to make their windows even more affordable.

Styles

Milgard offers all of the most popular window styles: single-hung, double-hung, casement, awning, picture, and slider. They also have a selection of specialty styles, like radius windows which use at least one curved edge. They also offer Jalousie, garden, and bay windows.

Company Reputation

Milgard has an A rating with the Better Business Bureau, which means that they meet the BBB’s standards for fairness and transparency when working with customers. Reviews of their products across the web suggest that Milgard customers are highly satisfied, and in J.D. Power’s most recent U.S. Windows and Patio Doors Satisfaction Study, Milgard earned an 853 out of 1,000, which places it just a hair below the industry average of 854 when it comes to customer satisfaction.

Cost

The cost of Milgard replacement windows is highly dependent on the series and whether any energy efficiency enhancements are important to the buyer. Buyers looking for Milgard’s most affordable windows should look at the Style Line Series or their Standard Aluminum Series. Milgard’s lowest cost windows start in the mid- to high-hundreds for certain lines and styles, but can of course come in much higher than that. Energy efficiency can also be important as a cost factor for certain lines, like the difference between the more expensive Thermally Improved Aluminum and its more affordable Standard Aluminum counterpart. In general, however, Milgard windows tend to be more affordable overall than windows from larger brands like Andersen and Pella, which makes Milgard a great choice for buyers on a budget.

Installation

Milgard doesn’t have the same network of partnered retailers who can also install the windows as competitors like Andersen and Pella. However, Milgard provides installation resources and guides for every window they make, and their website includes a dealer search tool where buyers can find locations to purchase Milgard windows. Many of these dealers offer their own installation services, though buyers should be careful to ask about any dealer warranties on installation if they go this route.

Warranties

Milgard recently shifted from offering full lifetime warranties on almost all of their windows to more of a mixture of full and limited warranties depending on the line. Milgard offers full lifetime warranties on its Tuscany Series and Trinsic Series, its highest cost lines, which contributes to the quality of those options as an investment. The Style Line, Ultra, Thermally Improved Aluminum, and Standard Aluminum Series now have limited lifetime warranties. You can read more about the specific terms of Milgard’s warranty options, including sample documents, on Milgard’s website.

Recommendation

While Milgard does not offer a series of wood or wood-clad windows, this means that all of their lines use more affordable materials like vinyl, fiberglass, and aluminum. As a result, Milgard offers high-quality windows in a variety of styles at a reasonable price. For this reason, we rate Milgard as having the Best Replacement Windows for Buyers on a Budget.

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Additional Information

Window Components

• Head – The head is the horizontal component of the casing.
• Sill – The sill, or stool, is the horizontal component that sits at the bottom of the window and appears as a small shelf protruding into the interior of the home.
• Sash (Lower/Upper) – The sash is a structural frame that holds the glass in place and consists of both the stiles and rails. 
• Stile – Stiles are located on the sides of the window and serve as the major vertical supports of the window sash. 
• Rail – Rails are the horizontal pieces located at the top and bottom of the sash that connect the stiles and also help to hold the glass in place. 
• Muntin – Muntins are the window grids. Sometimes, they help to hold the glass in place, and sometimes they simply serve as decoration. 
• Jamb – Jambs are the side pieces running from the top to the bottom of the window that make up the window frame and hold the sash in place.
• Channel – The channel is a groove where the sash slides that serves to provide a seal for the window.
• Latch – The latch is a locking mechanism that serves to both lock and seal the window. 

Other components of windows not depicted in the image include:

• Casing – The casing is the horizontal and vertical molding that provides a frame for the window and gives the window an overall finished appearance. 
• Glazing – The glazing is the most apparent component of the window as it refers to the glass itself. 
• Operator – The operator is a hand-cranked device that allows a casement or awning type of window to be opened or closed. 
• Scissor/Extension Arm – The scissor/extension arm is what is extended by use of the operator and enables the window to open and close.

Best Time of Year to Replace Windows

Window installation can take several weeks, and while they can be installed at any time of the year, the seasons do offer advantages and disadvantages, which will be discussed below. 

While it might not be such an obvious choice, having replacement windows installed during late fall, winter, or early spring, might prove to be a cost-effective decision for the homeowner. In fact, fewer homeowners purchase replacement windows during the colder months, which means that installers have a limited number of clients and may offer discount prices. 

While replacement windows can usually be installed in cold weather, extreme temperatures can halt the installation process, as foams and sealants become difficult to work with. However, because this time of year is off-peak, rescheduling is far easier. While it may seem like the entire house will freeze during a winter installation, this is avoided by closing off one room at a time. Altogether, a winter installation can save a lot of money with limited discomfort.

Most homeowners opt for replacement window installation to take place in late spring, summer, or early fall. Because of this, the demand for installers is more competitive, which can lead to higher prices. Schedule a date early on to ensure the job is completed when desired. While it might be more difficult to get on the schedule during the warmer months, do note that installations performed during the warmer months are completed more quickly. Discomfort experienced due to the heat and humidity entering the home during the installation will be minimal since jobs are performed faster during the warm months. Ultimately, while the homeowner could pay slightly more for convenience, a summer installation can have a quicker turnaround.

When replacing windows, homeowners can choose to either install the windows themselves (DIY) or hire a professional contractor. Professional contractors include both independent third parties or certified dealers. But before deciding on who will actually do the work, it’s important to understand the basic structural components of a window and then consider when is the best time of year to do the work. 

How to Measure for Replacement Windows

Before purchasing replacement windows, be sure to measure your current windows to ensure a proper fit. To buy a replacement window, the buyer needs to know the height, width, and depth measurements. Read below to learn how to correctly measure window openings before buying replacement windows.

• Square – The first step to measuring window openings for new replacement windows is to check the existing window frame for square alignment. From the interior of the home, hold a tape measure in the top right corner. Extend the tape diagonally across the window to the lower left corner and record the measurement. Now follow the same procedure for the opposite corner. Compare the two measurements. If they are within ¼-inch of each other, then most standard replacement window sizes will tightly fit in the window opening. On the other hand, if the difference between the two measurements is greater than ¼-inch, the frame will first need to be properly squared before installing new windows. 
• Width – Measure the window width horizontally from the inside jambs in three places: the top, middle, and bottom. Be sure to measure from the surface of the jambs while excluding any trim. The shortest measurement should be used as the width of the window opening.
• Height – Measure the window height vertically from the window sill to the top of the window opening. Again, exclude any trim and take three measurements—left, right, and center. The smallest measurement is the height of the window opening. 
• Depth – Measure the window depth by measuring from the outside edge of the window frame to the inside edge of the window frame. Repeat this process several times around the window frame and use the smallest measurement to determine the depth of the window opening. A 3 ¼-inch depth is necessary for replacement windows.

With these measurements, a homeowner can know exactly which size replacement windows they’ll need to replace their current windows. Individuals should not attempt to buy replacement windows without this information. The video below, from Pella, demonstrates how to measure width and height:

Professional Installation

For homeowners who decide to hire a professional contractor or certified dealer to install replacement windows, the installation process is much simpler and far less involved. The homeowner should simply aid in the installation process to ensure that it is a smooth process. 

First, be prepared for the installation crew during the time frame that was selected. Depending on the number of windows being replaced, the job can take a couple of days to complete. Next, be sure to prepare the home. This includes doing the following: deactivating alarm systems connected to the current windows, clearing the work area of fragile or delicate objects and window treatments, covering and moving furniture to increase protection from dust, trimming exterior landscaping if necessary, preparing a workspace for the installers to stage tools and equipment, and finally, keeping children and pets away from the workspace during the length of the installation. 

The installers will then work to remove the old windows and install the new windows per the manufacturer’s guidelines. The new windows will be insulated, trimmed, and sealed, and any debris created during the installation process will be hauled away. After the installation is complete, perform a walk-through inspection with the installers and be sure to have an understanding of how the new windows operate.

How to Install Replacement Windows (DIY)

The level of skill required to replace windows varies depending on the specifics of the job. For example, installing full frame, or new construction, windows is more complicated than installing insert, or replacement windows. This portion of the guide provides step-by-step instructions for installing replacement windows.

Replacement window installation, also known as insert or pocket installation, uses a window’s existing frame and exterior trim. The frame must be in good condition with no rot or deterioration and must also be square. For DIY-ers, this is an easier installation than full frame. Before starting the installation process, gather the proper tools and materials, read an installation guide like this one, and watch instructional videos. Then, use the steps below to remove the old windows and install the new windows. Here is a list of the necessary tools and materials for the job:

Tools

• Drill and Bits
• Oscillating Tool and Blades
• Shop Vacuum
• Level 
• Caulk Gun 
• Tape Measure 
• Utility Knife
• Pry Bar
• Putty Knife
• Hammer
• Nail Set
• Paint Multitool
• Screwdriver
• Drop Cloth
• Safety Glasses
• Work Gloves
• Hearing Protection
• Dust Mask

Materials

• Replacement Window
• Flashing Tape
• Wood Filler
• Silicone Caulk
• Paintable Latex Caulk
• Window Spray Foam Insulation
• Shims
• Finish Nails
• Backer Rod Weatherstripping (Optional)

Removing the Old Window

These steps can vary depending on how the original window is constructed, but generally, a similar procedure will work for most windows. It is a good idea to do this with at least two people present, though a single person can handle it for smaller windows.

1. From inside, remove any stops that cover the window casing and its connection to the wall. Be careful not to break or damage these pieces if they are going to be used when the new window is installed.
2. Use a putty knife to separate the original window jamb from the wall. 
3. Unscrew any screws, and saw or pry out any nails connecting the original window to the wall.
4. Pull the old window from the wall.

Installing the New Window

Once the old window has been removed, it is time to install the new window. Follow the steps below when installing new replacement windows, and be sure to reference any installation materials that were included with the new replacement window. 

1. Clean the area. Vacuum any debris and particles, and wipe down the opening where the original window existed. Scrape away any chipped paint from the area, and make sure the opening is smooth, clean, and ready for the replacement to be inserted. This will help the new window fit in snuggly. 
2. Run a bead of caulking along the surface that the replacement window will be pressed against, and at least one line of caulking along the window sill on which the window will sit. This will help create a seal that provides insulation around the window.
3. Place the new window into the opening, setting the bottom in first and centering the window right and left in the opening.
4. Insert shims along the sides to make sure the window is snug and held tightly within the opening.
5. Screw the new window in place using the screws and designated holes provided by the manufacturer. 
6. Add caulking around the edges of the window, both from inside and outside.
7. Replace the stops that were removed with the original window, nailing them back into place.

This video from Ask This Old House demonstrates this straightforward process:

Improving the Energy Efficiency of Windows

For homeowners who have recently installed replacement windows but want an extra boost in savings, or for those who are not yet ready to purchase replacement windows, additional measures can be taken to further decrease energy usage and increase overall savings. Most of these measures are relatively inexpensive and include: caulk and weather stripping, awnings, window treatments, shutters, and window film.

Caulk – One key feature of replacement windows is the fresh seal created around the window in order to prevent drafts from entering the home. Whether a home’s windows are old or new, the caulk and weather stripping around the window should be checked on a yearly basis in order to keep pesky drafts out of the home. When the seal has deteriorated, simply replace it with a fresh seal. 

Awnings – Awnings are a type of shade installed on the exterior of the window that work to shelter the window from the sun’s heat and glare. When installed in tandem with replacement windows, a considerable amount of solar heat is blocked from entering the home. Awnings are fixed or retractable and can be installed over individual windows or attached to a large portion of the home. Many awnings are made out of synthetic materials that resist water, mildew, and fading. Light-colored awnings reflect the most sunlight. 

Window Treatments – Draperies can improve the energy efficiency of replacement windows by not only reducing cold drafts, but also preventing heat from entering or leaving the home. Drapes can also be used to control how much light enters the home as desired. Window blinds are another option for heat reduction, and work best when used in conjunction with drapes.

Shutters – Shutters can be installed on the interior or exterior of a home and work similarly to blinds. In addition to offering protection from the sun, they can protect against wind.

Window Film – While window film is not a necessary component for new replacement windows, it can certainly aid in reducing the amount of heat that enters the home before a homeowner is ready to purchase replacement windows. Films work by tinting the window and can be temporary or permanent fixtures. While films will effectively reduce the amount of heat entering the home, it is important to note that they will also reduce visibility through the window. 

Extending Lifetime of Windows

The integrity of replacement windows will be protected by properly caring for the windows. Be sure to carefully operate the windows, clean them regularly, use window treatments, and perform a yearly inspection in order to extend the lifetime of your replacement windows.

Window Operation – Gentle use of replacement windows is a surefire way to prolong their lifetime. Slamming, on the other hand, can cause a wooden window frame to crack and interfere with the window’s longevity. Be sure to always operate the windows with a gentle touch in order to make them last as long as possible.

Clean Windows – Windows are exposed to harsh outdoor elements on a daily basis, so it is important to wash them on a regular interval every few months. Below are some useful tips when it comes to cleaning replacement windows.

• Clean glass: To clean the glass of replacement windows, use a mild detergent or vinegar and water mixture that is designed for use on glass. Avoid any products that contain hydrofluoric or phosphoric acid, as these are chemicals that cause corrosion. To get a clean and streak-free shine, first rinse the window with plain water. Next, use a sponge to wash the window with a detergent or cleaning solution by applying even pressure horizontally and vertically along the window, while being sure not to allow the solution to puddle up on vinyl surfaces. Rinse the window thoroughly with plain water to ensure that the solution has been fully removed. Lastly, dry the window with a clean, lint-free cloth.
• Clean frames: Any time that the window glass is cleaned, the window frame should be as well. Simply use a soft sponge and the same mild detergent or solution that was previously used on the glass to softly remove pollution, dirt, salt, or other residue from the frame, paying extra attention not to scratch or scrape the frame. 
• Clean screens: To clean a fly screen, remove it from the window before washing. Use a garden hose, soft bristled brush, and warm, soapy water to scrub both sides of the screen before re-installing the screen. When using this method, make sure that the water pressure is not too strong as this can cause the screen to stretch. For other types of screens that are fixed, follow the same procedure, but use a bucket of water instead of a garden hose.
• Clean hardware: In order to fully clean a window, make sure to clean the interior hardware in addition to the glass panes. If necessary, first vacuum large debris from the track before using a damp cloth to remove dirt and grime. Wipe down latches, locks, and other hardware. Verify that drainage holes are unobstructed and check that the window opens and closes smoothly. 

Window Treatment – Most window treatments are multi-functional: they provide privacy, block light, and add personality to a room. Window film is one of the simplest window treatment options to install because it does not require the use of hardware. Film can serve various purposes, depending on the needs of the homeowner. Some types of film reduce glare by blocking UV rays, while others have a low-emissive coating to retain winter heat. Even more options exist to provide privacy control and a decorative touch with their mirrored, etched, frosted, or embellished appearance. 

Window Inspection – Perform a yearly inspection to ensure that a home’s replacement windows are working as expected. Check the window for any leaks and be sure to apply a fresh seal around the window if there are leaks. If a problem such as condensation is observed, be sure to have it repaired before it worsens and requires the entire window to be replaced. For wood window frames, make it a point to reseal or repaint every five years in order to preserve the frame. Finally, be sure to lubricate the track and any hardware, such as: locks, latches, or hinges, in order to keep them operating smoothly.

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References

• Better Business Bureau
• Andersen
• Pella
• Milgard
• Energy Star
• National Fenestration Rating Council
• Database of State Incentives for Renewables & Efficiency
• Ask This Old House
• Home Depot
• Lowe’s