20 Best Window Companies in Accokeek, MD (2024 Reviews)

Looking to upgrade your home's windows? We’ve got you covered in this list of the best window installation companies.

We analyzed all the top-rated window companies in Accokeek and selected the best 20 based on:

  • Customer reviews
  • Window installation expertise
  • Popularity with home-owners like you
EcoWatch Local Advisors

By EcoWatch Local Advisors

Updated June 24, 2024

Why you can trust EcoWatch

Our panel of energy experts work tirelessly to create unbiased reviews and informative content to help homeowners make educated decisions. No other windows site has covered energy efficiency and sustainability as long as EcoWatch, which means we're going to help you find windows replacements that will save on your energy bill and put more money back in your wallet.

Although green energy sources like wind and solar are important when it comes to reducing your carbon footprint, improving your home’s efficiency can also have a considerable impact on home energy conservation. Drafty or leaky windows can make your home uncomfortable in the summer or winter.

Replacement windows improve the insulation in your home, not only making you more comfortable during extreme temperatures, but also saving you money and helping the environment.

Unlike other sites, EcoWatch ranks window installation companies on energy efficiency while also considering cost, customer satisfaction and service area.

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Best Availability

Renewal by Andersen

★★★★★
4.5
  • Great Industry Reputation
  • Award-winning Company
  • Member of US Green Building Council
  • Manufactures products in-house
Save $375 Off Each Window
Get Estimate

Best Energy-Efficient Features

Champion

★★★★★
4.5
  • Many years of experience
  • Low prices relative to competitors
  • Limetime warranty
Save 35% + $100 off per window!
Get Estimate

Power Home

★★★★★
4.5
  • Uses eco-friendly materials
  • Well-trained, certified installers
  • Lifetime or lengthy warranty
Next-Day Appointments Available
Get Estimate

Best Window Installation & Replacement Companies in Accokeek

The EcoWatch team assessed dozens of companies that serve the Accokeek area to find the best window installation companies by our standards. The providers in this article scored best in our review categories, which include energy-efficient offerings, availability, customer service, local expertise, price and more.

Window World logo
Best Affordability

Window World

★★★★★
BBB Rating: A+
Locations: Nationwide
Founded: 1995
Pros:
  • Pros icon EnergyStar Partner
  • Pros icon Large serice area
  • Pros icon Low prices relative to competitors
  • Pros icon Great industry reputation
  • Pros icon Lifetime warranty
Cons:
  • Pros icon Quality of service will depend on your area

Window World is the largest window replacement company in the country, known for its vinyl windows and affordability. Window World has over 27 years of experience in the windows industry, and it currently serves 200 locations nationwide.

If you’re looking for a company that is certified by the Environmental Protection Agency (EPA) and Energy Star and supports charities like St. Jude Children’s Research Hospital, Window World may be the provider for you.

Energy Efficiency of Window World Windows

Window World is an Energy Star partner with a variety of energy-efficient windows. Note that not all of the company’s windows are Energy Star certified, so make sure to mention that you want energy-efficient windows to your Window World representative when inquiring about services.

How much does Window World cost in Accokeek?

Prices aren’t displayed on Window World’s website, but it's known for offering some of the most affordable window installations around. The best way to get more accurate pricing information is to receive a free quote from the company.

Renewal by Andersen logo
Best Overall

Renewal by Andersen

★★★★★
BBB Rating: A
Locations: Nationwide
Founded: 1995
Pros:
  • Pros icon Great industry reputation
  • Pros icon Award-winning company
  • Pros icon Member of US Green Building Council
  • Pros icon Manufactures products in-house
Cons:
  • Pros icon No lifetime warranty
  • Pros icon More expensive than competition

Renewal by Andersen is a subsidiary of the Andersen Corporation, a major manufacturer of windows and doors. Andersen has over 27 years of experience in the windows industry, and it currently serves nearly every state except Mississippi and West Virginia.

If you’re looking for a company that uses in-home estimates and advanced digital tools to help you plan and visualize your project before getting started, Andersen may be the provider for you.

Energy Efficiency of Renewal by Andersen Windows

Renewal by Andersen is an Energy Star partner with a variety of energy-efficient windows. Note that not all of the company’s windows are Energy Star certified, so make sure to mention that you want energy-efficient windows to your Andersen representative when inquiring about services.

How much does Renewal by Andersen cost in Accokeek?

Prices aren’t displayed on Andersen’s website, but based on customer feedback, you can expect to pay anywhere between $750 to $1,250 per window for an installation with Andersen. The best way to get more accurate pricing information is to receive a free quote from the company.

Aeroseal Windows logo
Best for Businesses

Aeroseal Windows

★★★★★
BBB Rating: A+
Locations: Regional
Founded: 1999
Pros:
  • Pros icon Many years of experience
  • Pros icon Great industry reputation
  • Pros icon Low number of customer complaints
  • Pros icon Manufactures products in-house
  • Pros icon Custom Designs
Cons:
  • Pros icon No lifetime warranty
  • Pros icon Not ideal for residential installations

Aeroseal Windows is an installer that mainly serves commercial and multifamily properties, and also specializes in railings. If you’re looking for residential window installations, you should probably refer to one of the other companies on this list. Aeroseal has over 23 years of experience in the windows industry, and it currently serves 13 states and Washington D.C.

If you’re looking for a company that installs windows and doors at businesses across the Eastern U.S, Aeroseal may be the provider for you.

Energy Efficiency of Aeroseal Windows Windows

Aeroseal Windows is an Energy Star partner with a variety of energy-efficient windows. Note that not all of the company’s windows are Energy Star certified, so make sure to mention that you want energy-efficient windows to your Aeroseal representative when inquiring about services.

How much does Aeroseal Windows cost in Accokeek?

Prices aren’t displayed on Aeroseal’s website, but it provides high-quality windows at a competitive price point. The best way to get more accurate pricing information is to receive a free quote from the company.

Window Nation logo
Best for Residential Windows

Window Nation

★★★★★
BBB Rating: A
Locations: Regional
Founded: 2006
Pros:
  • Pros icon Award-winning company
  • Pros icon Manufactures products in-house
  • Pros icon Custom designs
  • Pros icon Wide variety of products and services
Cons:
  • Pros icon Installation not covered by warranty
  • Pros icon Limited service area

Window Nation is a company that serves hundreds of thousands of homeowners, mostly in the mid-Atlantic region of the U.S. Window Nation has over 16 years of experience in the windows industry, and it currently serves residents within 75 miles of its showrooms, which are in 13 states.

If you’re looking for a company that gives customers the opportunity to view products and to speak to a representative in person in its showrooms, Window Nation may be the provider for you.

Energy Efficiency of Window Nation Windows

Window Nation is an Energy Star partner with a variety of energy-efficient windows. Note that not all of the company’s windows are Energy Star certified, so make sure to mention that you want energy-efficient windows to your Window Nation representative when inquiring about services.

How much does Window Nation cost in Accokeek?

Prices aren’t displayed on Window Nation’s website, but based on customer feedback, you can expect to pay between $300 and $525 per window installed, making it a more affordable option compared to competitors. The best way to get more accurate pricing information is to receive a free quote from the company.

We strive to remain unbiased and transparent by including pros and cons for every provider. Additionally, any partnerships do not affect our rankings.

More Window Companies in Accokeek

Renewal by Andersen of the Capital Region

Fairfax, VA
4.8
★★★★★
  • Pros icon Educational Website
  • Pros icon Free assessment
  • Pros icon Price Transparency
  • Pros icon Good Customer Service

Services Offered

  • Service icon Glass Doors
  • Service icon Double-Hung
  • Service icon Skylights
  • Service icon Window Replacement/Installation
  • Service icon Bay Windows

Website: https://www.renewalbyandersen.com/window-company/085-capital-region/about-us
Address: 2814 Merrilee Dr A, Fairfax, VA 22031
Phone: (703) 719-4052

Champion Replacement Windows of Baltimore

Rosedale, MD
3.2
★★★★★
  • Pros icon Sunrooms
  • Pros icon Free assessment
  • Pros icon Good Customer Service
  • Pros icon Single-source accountability
  • Pros icon Products made in the USA
  • Pros icon Price Transparency

Services Offered

  • Service icon Window Replacement/Installation
  • Service icon Double-Hung
  • Service icon Glass Doors
  • Service icon Bay Windows

Website: https://www.championwindow.com/Baltimore/
Address: 23 Fontana Ln, Rosedale, MD 21237
Phone: (410) 202-8636

Window Nation

Lorton, VA
4.5
★★★★★
  • Pros icon Free assessment
  • Pros icon Educational Website
  • Pros icon Good Customer Service
  • Pros icon Price Transparency

Services Offered

  • Service icon Bay Windows
  • Service icon Window Replacement/Installation
  • Service icon Energy-Efficient Options
  • Service icon Custom Window Designs
  • Service icon Vinyl Frames
  • Service icon Double-Hung
  • Service icon Glass Doors

Website: https://www.windownation.com/northern-va-showroom
Address: 8198 Terminal Rd #105, Lorton, VA 22079
Phone: (703) 372-4540

Metric Windows Shower Doors and Glass Repair

Alexandria, VA
4.9
★★★★★
  • Pros icon Good Customer Service
  • Pros icon Timely Service
  • Pros icon Free assessment
  • Pros icon Price Transparency
  • Pros icon Educational Website

Services Offered

  • Service icon Mirrors
  • Service icon Window Repair
  • Service icon Glass Showers
  • Service icon Glass Repair
  • Service icon Metal Frames
  • Service icon Tempered Glass
  • Service icon Glass Doors
  • Service icon Window Replacement/Installation

Website: https://www.metricwindows.com/
Address: 3917 El Camino Pl, Alexandria, VA 22309
Phone: (571) 218-0759

Window World of Southern Maryland

Waldorf, MD
4.9
★★★★★
  • Pros icon Educational Website
  • Pros icon Good Customer Service
  • Pros icon Price Transparency
  • Pros icon Free assessment

Services Offered

  • Service icon Double-Hung
  • Service icon Vinyl Frames
  • Service icon Glass Doors
  • Service icon Window Replacement/Installation
  • Service icon Bay Windows

Website: https://www.windowworlddc.com/
Address: 12370 Waldorf Business Square, Waldorf, MD 20601
Phone: (301) 663-4451

Platinum Home Design, LLC

La Plata, MD
4.9
★★★★★
  • Pros icon Educational Website
  • Pros icon Price Transparency
  • Pros icon Free assessment
  • Pros icon Good Customer Service
  • Pros icon Timely Service

Services Offered

  • Service icon Window Replacement/Installation

Website: http://platinumhomedesignllc.com/
Address: 9375 Chesapeake St Suite 225, La Plata, MD 20646
Phone: (301) 659-8080

Southernwood Roofing & Siding, LLC

La Plata, MD
4.8
★★★★★
  • Pros icon Good Customer Service
  • Pros icon Free assessment
  • Pros icon Price Transparency
  • Pros icon Educational Website

Services Offered

  • Service icon Window Replacement/Installation
  • Service icon Glass Doors
  • Service icon Energy-Efficient Options

Website: https://www.southernwoodllc.com/
Address: 5895 Crain Hwy, La Plata, MD 20646
Phone: (301) 720-1640

See-Thru Windows, Doors & Home Improvements

Waldorf, MD
4.5
★★★★★
  • Pros icon Good Customer Service
  • Pros icon Price Transparency
  • Pros icon Free assessment

Services Offered

  • Service icon Double-Hung
  • Service icon Glass Doors
  • Service icon Glass Showers
  • Service icon Wood Frames
  • Service icon Window Replacement/Installation
  • Service icon Bay Windows

Website: https://www.see-thruwindows.com/
Address: 2640 Crain Hwy, Waldorf, MD 20601
Phone: (877) 733-8478

Old Town Glass & Window Repair

Alexandria, VA
5.0
★★★★★
  • Pros icon Affordable prices
  • Pros icon Good Customer Service
  • Pros icon Price Transparency
  • Pros icon Third-generation glassier
  • Pros icon Free assessment
  • Pros icon Large online project gallery

Services Offered

  • Service icon Glass Doors
  • Service icon Mirrors
  • Service icon Custom Glass
  • Service icon Window Replacement/Installation
  • Service icon Glass Showers
  • Service icon Glass Repair

Website: http://www.oldtownglassandmirror.com/
Address: 244 S Reynolds St, Alexandria, VA 22304
Phone: (703) 609-3508

Vinyl-Lite Window Factory and Showroom

Lorton, VA
4.4
★★★★★
  • Pros icon Price Transparency
  • Pros icon Free assessment
  • Pros icon Good Customer Service
  • Pros icon Educational Website

Services Offered

  • Service icon Glass Doors
  • Service icon Bay Windows
  • Service icon Vinyl Frames
  • Service icon Energy-Efficient Options
  • Service icon Double-Hung
  • Service icon Window Replacement/Installation

Website: https://www.vinyl-lite.com/
Address: 8815 Telegraph Rd, Lorton, VA 22079
Phone: (703) 550-7766

DISTRICT CAPITOL GLASS LLC

Alexandria, VA
5.0
★★★★★
  • Pros icon Educational Website
  • Pros icon Free assessment
  • Pros icon Price Transparency
  • Pros icon Good Customer Service

Services Offered

  • Service icon Glass Showers
  • Service icon Window Repair
  • Service icon Window Replacement/Installation
  • Service icon Glass Repair
  • Service icon Glass Doors
  • Service icon Mirrors
  • Service icon Screen Repair

Website: https://districtcapitolglass.com/
Address: 205 Yoakum Pkwy #1119, Alexandria, VA 22304
Phone: (571) 344-4416

Anderson Glass Contractors - Frameless Shower Door, Glass Door in Alexandria VA

Marlow Heights, MD
5.0
★★★★★
  • Pros icon Price Transparency
  • Pros icon Free in-person consultation
  • Pros icon 24-hour emergency availability
  • Pros icon Custom glass services
  • Pros icon Good Customer Service
  • Pros icon Educational Website
  • Pros icon Free assessment

Services Offered

  • Service icon Mirrors
  • Service icon Glass Showers
  • Service icon Window Replacement/Installation
  • Service icon Glass Repair
  • Service icon Custom Glass
  • Service icon Glass Doors

Website: https://precisionglassexperts.com/
Address: 4570 Beech Rd, Marlow Heights, MD 20748
Phone: (703) 623-2223

Potomac Glass Pro

Woodbridge, VA
4.9
★★★★★
  • Pros icon Free assessment
  • Pros icon Good Customer Service

Services Offered

  • Service icon Double-Hung
  • Service icon Tempered Glass
  • Service icon Energy-Efficient Options
  • Service icon Custom Glass
  • Service icon Glass Repair
  • Service icon Mirrors
  • Service icon Glass Doors
  • Service icon Skylights
  • Service icon Window Replacement/Installation
  • Service icon Window Repair
  • Service icon Glass Showers

Website: http://www.potomacglasspro.com/
Address: 1941 Heatherbrook Ct, Woodbridge, VA 22192
Phone: (571) 213-2205

Advanced Window & Glass Repair, LLC

Woodbridge, VA
5.0
★★★★★
  • Pros icon Free assessment
  • Pros icon Educational Website
  • Pros icon Timely Service
  • Pros icon Good Customer Service
  • Pros icon Price Transparency

Services Offered

  • Service icon Vinyl Frames
  • Service icon Mirrors
  • Service icon Energy-Efficient Options
  • Service icon Double-Hung
  • Service icon Fiberglass Frames
  • Service icon Glass Showers
  • Service icon Bay Windows
  • Service icon Custom Glass
  • Service icon Glass Repair
  • Service icon Window Replacement/Installation
  • Service icon Tempered Glass
  • Service icon Glass Doors
  • Service icon Window Repair

Website: http://advancedwindowglassrepair.com/
Address: 2159 Potomac Club Pkwy, Woodbridge, VA 22191
Phone: (571) 351-3692

Sunshine Contracting Corporation

Woodbridge, VA
4.7
★★★★★
  • Pros icon Educational Website
  • Pros icon Price Transparency
  • Pros icon Timely Service
  • Pros icon Good Customer Service
  • Pros icon Free assessment

Services Offered

  • Service icon Energy-Efficient Options
  • Service icon Vinyl Frames
  • Service icon Window Replacement/Installation
  • Service icon Fiberglass Frames
  • Service icon Glass Doors

Website: https://sunshinecontractingcorp.com/
Address: 12958 Harbor Dr, Woodbridge, VA 22192
Phone: (703) 499-8654

District Window & Glass Repair

Oxon Hill, MD
3.3
★★★★★
  • Pros icon Free assessment
  • Pros icon Full-service installation
  • Pros icon Free in-person consultation
  • Pros icon Available 24/7

Services Offered

  • Service icon Glass Repair
  • Service icon Window Replacement/Installation
  • Service icon Storm/Impact Windows
  • Service icon Window Repair
  • Service icon Vinyl Frames

Website: http://districtwindowandglassrepair.com/
Address: 704 Leyte Pl, Oxon Hill, MD 20745
Phone: (202) 489-9100

Sunbrite Windows and Doors

Alexandria, VA
3.1
★★★★★
  • Pros icon Price Transparency
  • Pros icon Free assessment
  • Pros icon Good Customer Service

Services Offered

  • Service icon Window Replacement/Installation

Website: http://sunbritewindowsanddoors.com/
Address: 631 S Patrick St, Alexandria, VA 22314
Phone: (703) 647-9940

Penwin Roofing & Windows

Clinton, MD
3.2
★★★★★
  • Pros icon Price Transparency
  • Pros icon Good Customer Service
  • Pros icon Educational Website
  • Pros icon Free assessment

Services Offered

  • Service icon Window Replacement/Installation

Website: http://penwinwindows.com/
Address: 8787 Branch Ave, Clinton, MD 20735
Phone: (301) 296-8444

Window and Door Showplace

Alexandria, VA
3.0
★★★★★
  • Pros icon Educational Website
  • Pros icon Free assessment
  • Pros icon Price Transparency
  • Pros icon Timely Service
  • Pros icon Good Customer Service

Services Offered

  • Service icon Window Replacement/Installation
  • Service icon Double-Hung
  • Service icon Bay Windows
  • Service icon Glass Doors

Website: https://www.wdshowplace.com/
Address: 810 N Fairfax St, Alexandria, VA 22314
Phone: (703) 780-7800

Thompson Creek Window Company Manufacturing Center

Upper Marlboro, MD
4.3
★★★★★
  • Pros icon Custom-made products
  • Pros icon Timely Service
  • Pros icon Educational Website
  • Pros icon Good Customer Service
  • Pros icon Full-service
  • Pros icon Free video consulatation
  • Pros icon Free assessment
  • Pros icon Price Transparency

Services Offered

  • Service icon Bay Windows
  • Service icon Custom Window Designs
  • Service icon Glass Doors
  • Service icon Glass Showers
  • Service icon Window Replacement/Installation
  • Service icon Energy-Efficient Options
  • Service icon Double-Hung

Website: https://www.thompsoncreek.com/
Address: 8100 Penn Randall Pl, Upper Marlboro, MD 20772
Phone: (301) 917-3467
Accokeek Window Cost Calculator

Calculate how much you can expect to pay for window installation and replacement in Accokeek, MD using our customized window cost calculator.

Estimated Window Cost:
161 homeowners have requested a free estimate in the last 3 days.

Estimates will vary based on window dimensions and other unique factors to your home. Getting in touch with a local window installer is the best way to get an accurate cost estimate for your home.

How Installing Energy-Efficient Windows in Accokeek Saves You Money

Upgrading to energy-efficient windows can improve the comfort of your home and help you save on power bills. Here are more ways switching out your windows could help you:

  • Protect your valuables from fading: When you switch to energy-efficient windows with low-emissivity coatings, your floors, carpets and furniture will fade less due to their ability to filter out damaging UV rays.
  • Protect your investment: The older your home is, the more likely you are to benefit from switching to energy-efficient windows. Older homes usually have windows that are outdated, leaky or maybe even damaged in some way. Upgrading your windows could help raise the value of your property if you decide to sell.
  • Save money on electricity bills: The Department of Energy estimates that heat gained or lost via windows accounts for about 25-30% of energy use in your home. Switching to energy-efficient windows can help decrease that number, which helps you save some money on your bills.
  • Reduce your carbon footprint: By using less energy after upgrading to energy-efficient windows, you’ll also be cutting your indirect greenhouse gas emissions by about 12%, according to Energy Star.

Estimated Cost of Window Replacement in Accokeek

Each window installation company provides various services and has varying price points depending on several factors.

How Much Do New Windows Cost?

Typically, Accokeek homeowners can expect their window installations to range from $250 to $1,200. The most common installations sit at around $600. These amounts vary based on the specifics of your installation, including type, number of windows, material, the location of your home, size and more.

Keep in mind that energy-efficient windows may come at a higher price point, but Energy Star predicts the upgrade will save you between $101 and $583 per year when replacing single-pane windows and between $27 and $197 a year when you install double-pane, clear glass windows. These savings vary depending on your local climate, energy rates and individual home characteristics.

How much your window installation costs will also vary depending on the type of material you choose for the frames. Wood windows are generally the most expensive, but it depends on whether they are 100% wood or clad with aluminum or vinyl. Fiberglass windows also tend to be somewhat more expensive than vinyl, but they are more efficient.

What Services do Window Installers Offer?

In regard to window installations, in general there are two kinds that your installer will offer: full-frame and pocket installations.

Full-frame installations involve replacing the whole window — the sill, frame, trim and all. These are most common when you want to change the style of your window or when it has significant deterioration. Full-frame installations involve more time and labor and will increase overall costs. Pocket installations (or retrofits) involve replacing a window within the existing frame, which makes pocket installations less labor-intensive and costly. But, if the frame has any rot or deterioration, you should opt for a full-frame installation instead.

Your window installation company can advise you on the best type for your project. In Accokeek, the decision will mostly be based on how much damage there is currently and how old your existing frames are.

Advertisement

Best Availability

Renewal by Andersen

★★★★★
4.5
  • Great Industry Reputation
  • Award-winning Company
  • Member of US Green Building Council
  • Manufactures products in-house
Save $375 Off Each Window
Get Estimate

Best Energy-Efficient Features

Champion

★★★★★
4.5
  • Many years of experience
  • Low prices relative to competitors
  • Limetime warranty
Save 35% + $100 off per window!
Get Estimate

Power Home

★★★★★
4.5
  • Uses eco-friendly materials
  • Well-trained, certified installers
  • Lifetime or lengthy warranty
Next-Day Appointments Available
Get Estimate

How We Choose the Best Window Installers in Accokeek

In our hunt to make your home improvements easier and more eco-friendly in Accokeek, the EcoWatch team landed on the above companies as the top window installation companies in the city. We’ve reviewed the best window installation companies in Accokeek mostly based on energy efficiency, as it’s the most sustainable option and the best one for homeowners. Energy-efficient windows have been shown to lower electricity bills by hundreds of dollars. Along with energy efficiency, our rating methodology is based on the following factors:

Service Area

Because this is a guide for Accokeek, we paid more attention to companies that provide services to the city. There are certainly reputable providers that didn’t make the cut because they wouldn’t be able to serve homeowners in Accokeek.

Work Quality

We’re willing to bet that you’re looking for professionals who do a great job installing windows. We’ve vetted each company in our guide to make sure its contractors are well-qualified and that the company has gotten plenty of positive customer feedback to vouch for its service.

Customer Reviews

Customer feedback is another very important review factor. If the majority of customers don’t have positive things to say about their experience with a certain window installation company, it won’t be featured on EcoWatch.

Cost

This one is a give-and-take: as with other services, cheap window installation companies may not provide the highest quality service. Still, we want to ensure we’re highlighting companies that offer a spectrum of price and financing options so they’re accessible to most homeowners.

Warranty

Protecting your investment in new windows is important to many homeowners. That’s why window installation companies that provide lengthy warranties for products, parts and labor rank higher with EcoWatch.

Years of Experience

Due to Accokeek’s climate, homeowners need to be wary of low efficiency, water damage and rot. We factored in local experience to reflect the ability of Accokeek window companies to prepare homes for these issues. If a company has less than 10 years of experience, it loses points in this category.

Accokeek, MD Window Replacement FAQs

What is the average cost to install new windows?

The typical cost to install one window ranges between $450 and $650. There are several factors that affect the price, including local labor costs, styles and sizes of windows, the materials used in designing the windows, the number of windows, your property’s location and how energy-efficient the windows are.

What are the different types of windows?

There are several different kinds of windows you can get for your home, including slider windows, bay windows, casement windows, awning windows, picture windows, transom windows and double-hung and single-hung windows.

What do window installers do?

Window installation professionals travel to your home to remove your old windows and replace them with new ones. Some providers install products sold by other companies, whereas others install their own windows. The installer will also clean up after the installation is done.

When is it time to replace your windows?

Windows have a typical lifespan of about 20 to 30 years. If your windows are older than that, then they probably need to be replaced. Apart from that, if your windows have damage anywhere on them, or they have become difficult to operate, they may be in need of replacement.