20 Best Window Companies in King of Prussia, PA (2024 Reviews)

Thinking of improving your home’s energy efficiency? The best window replacement companies can help.

We analyzed all the top-rated window companies in King of Prussia 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 February 01, 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.

The EcoWatch team is all about helping King of Prussia homeowners make their homes more eco-friendly. According to the Department of Energy, heat or cool air lost through outdated, drafty windows could be responsible for 25-30% of household energy climate control use.

That’s bad for both your wallet and the environment, but one of the top window installation companies can help with that.

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

Best Availability

Renewal by Andersen

★★★★★
4.5
  • Great industry reputation
  • Member of US Green Building Council
  • Manufactures products in-house
Buy One Window, Get One 40% OFF
Get Estimate

Best Energy-Efficient Features

Champion

★★★★★
4.5
  • Many years of experience
  • Low prices relative to competitors
  • Limetime warranty
Buy 2 Windows, Get 2 Free
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 King of Prussia

The EcoWatch Reviews team evaluated dozens of installers in King of Prussia to find the best window companies for our readers. The providers mentioned in this article passed our review standards for energy-efficient offerings as well as customer service, local expertise, price and beyond.

Window World logo
FAST QUOTE
as little as 30 seconds
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 provides windows expertise in King of Prussia. Window World has around 27 years of experience in the window replacement industry.

It is certified by the Environmental Protection Agency (EPA) and Energy Star and supports charities like St. Jude Children’s Research Hospital.

Energy Efficiency of Window World Windows

There are a wide range of window types available from Window World, some of which are Energy Star products. Its high-performance Low-E (low-emissivity) coatings and argon gas insulation offer exceptional efficiency and performance for any home.

How much does Window World cost in King of Prussia?

Prices are not available on Window World’s website because the cost of window replacement differs based on how many and what type(s) of windows you need. However, it's known for offering some of the most affordable window installations around. You can ask for a free quote on its website for more information about the cost.

Renewal by Andersen logo
FAST QUOTE
as little as 30 seconds
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 provides the best availability in King of Prussia. Andersen has around 27 years of experience in the window replacement industry.

It uses in-home estimates and advanced digital tools to help you plan and visualize your project before getting started.

Energy Efficiency of Renewal by Andersen Windows

There are a wide range of window types available from Renewal by Andersen, some of which are Energy Star products. A handful of windows manufactured by the Andersen corporation were awarded Energy Star’s “Most Efficient” in 2021, and Andersen was named Energy Star’s Partner of the Year in 2019.

How much does Renewal by Andersen cost in King of Prussia?

Prices are not available on Andersen’s website because the cost of window replacement differs based on how many and what type(s) of windows you need. However, based on customer feedback, you can expect to pay anywhere between $750 to $1,250 per window for an installation with Andersen. You can ask for a free quote on its website for more information about the cost.

Aeroseal Windows logo
FAST QUOTE
as little as 30 seconds
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 provides the best window installation for businesses in King of Prussia. Aeroseal has around 23 years of experience in the window replacement industry.

It installs windows and doors at businesses across the Eastern U.S.

Energy Efficiency of Aeroseal Windows Windows

There are a wide range of window types available from Aeroseal Windows, some of which are Energy Star products. The company claims it helps businesses save on energy expenses and reduce their carbon footprints with energy-efficient windows, as well as practices like Low-E glass coating, weatherstripping and more.

How much does Aeroseal Windows cost in King of Prussia?

Prices are not available on Aeroseal’s website because the cost of window replacement differs based on how many and what type(s) of windows you need. However, it provides high-quality windows at a competitive price point. You can ask for a free quote on its website for more information about the cost.

Universal Windows Direct logo
FAST QUOTE
as little as 30 seconds
Best Warranty

Universal Windows Direct

★★★★★
BBB Rating: A
Locations: Nationwide
Founded: 2002
Pros:
  • Pros icon Makes charitable contributions
  • Pros icon Manufactures products in-house
  • Pros icon Wide variety of products and services
  • Pros icon Lifetime warranty
Cons:
  • Pros icon Limited service area
  • Pros icon Some installations carried out by third-party contractors
  • Pros icon Quality of service will depend on your area

Universal Windows Direct provides the best warranty in King of Prussia. Universal has around 20 years of experience in the window replacement industry.

It has an industry-leading warranty covering products, parts and workmanship for life.

Energy Efficiency of Universal Windows Direct Windows

There are a wide range of window types available from Universal Windows Direct, some of which are Energy Star products. The company offers energy-efficient UniShield brand windows. According to its website, UniShield window packages have higher gas fill rates and longer gas retention than most other brands on the market, and they are Energy Star products.

How much does Universal Windows Direct cost in King of Prussia?

Prices are not available on Universal’s website because the cost of window replacement differs based on how many and what type(s) of windows you need. However, installations typically range from $225 to $425 per window based on customer feedback. That makes Universal Windows Direct more of a budget-friendly option for window repair and replacements. You can ask for a free quote on its website for more information about the cost.

Window Nation logo
FAST QUOTE
as little as 30 seconds
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 provides the best residential windows in King of Prussia. Window Nation has around 16 years of experience in the window replacement industry.

It gives customers the opportunity to view products and to speak to a representative in person in its showrooms.

Energy Efficiency of Window Nation Windows

There are a wide range of window types available from Window Nation, some of which are Energy Star products. Each product has windowpanes coated with a Low-E (low emissivity) glaze that prevents damaging UV rays from heating your home. Plus, the spaces between double- and triple-pane windows are filled with argon gas that’s been proven to improve home insulation.

How much does Window Nation cost in King of Prussia?

Prices are not available on Window Nation’s website because the cost of window replacement differs based on how many and what type(s) of windows you need. However, 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. You can ask for a free quote on its website for more information about the cost.

Please note that the companies in this section are national, meaning the quality of customer service may vary depending on your local team. We have tried to stay unbiased and transparent by listing both pros and cons for every provider.

More Window Companies in King of Prussia

Renewal by Andersen Window Replacement

King of Prussia, PA
4.9
★★★★★
  • Pros icon Educational Website
  • Pros icon Free assessment
  • Pros icon Good Customer Service
  • Pros icon Price Transparency

Services Offered

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

Website: https://www.renewalbyandersen.com/
Address: 761 5th Ave #3, King of Prussia, PA 19406
Phone: (484) 371-4056

Champion Replacement Windows of Philadelphia

Moorestown, NJ
4.5
★★★★★
  • Pros icon Good Customer Service
  • Pros icon Free assessment
  • Pros icon Price Transparency

Services Offered

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

Website: https://www.championwindow.com/Philadelphia/
Address: 1256 N Church St Unit 1, Moorestown, NJ 08057
Phone: (267) 297-4669

Window World of Philadelphia

Horsham, PA
4.8
★★★★★
  • Pros icon Price Transparency
  • Pros icon Educational Website
  • Pros icon Good Customer Service
  • Pros icon Free assessment

Services Offered

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

Website: https://www.windowworldphiladelphia.com/
Address: 253 Horsham Rd, Horsham, PA 19044
Phone: (215) 395-1608

Window Nation

Pennsauken Township, NJ
4.6
★★★★★
  • Pros icon Free assessment
  • Pros icon Educational Website
  • Pros icon Price Transparency
  • Pros icon Good Customer Service

Services Offered

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

Website: https://www.windownation.com/cherry-hill-showroom/
Address: 9256 Commerce Hwy, Pennsauken Township, NJ 08110
Phone: (856) 566-7200

Pella Windows & Doors of Plymouth Meeting

Plymouth Meeting, PA
5.0
★★★★★
  • Pros icon Free assessment
  • Pros icon Educational Website
  • Pros icon Price Transparency
  • Pros icon Good Customer Service

Services Offered

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

Website: https://www.pellabranch.com/philadelphia/showrooms/plymouth-meeting/
Address: 580 W Germantown Pike, Plymouth Meeting, PA 19462
Phone: (610) 648-0922

Ambiance Design

Blue Bell, PA
5.0
★★★★★
  • Pros icon Price Transparency
  • Pros icon Educational Website
  • Pros icon Free assessment
  • Pros icon Good Customer Service

Services Offered

  • Service icon Window Replacement/Installation
  • Service icon Custom Window Designs

Website: https://www.adwindowtreatments.com/
Address: 718 Dekalb Pike, Blue Bell, PA 19422
Phone: (267) 898-0200

Philadelphia

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

Services Offered

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

Website: https://www.thompsoncreek.com/
Address: 2564 Boulevard of the Generals #100B, Norristown, PA 19403
Phone: (267) 599-2847

Major Construction Inc Roofing and Siding

Eagleville, PA
4.9
★★★★★
  • Pros icon Free assessment
  • Pros icon Good Customer Service
  • Pros icon Educational Website
  • Pros icon Price Transparency

Services Offered

  • Service icon Window Replacement/Installation

Website: http://www.majorroofingandsiding.com/
Address: 28 Eagleville Rd, Eagleville, PA 19403
Phone: (610) 831-1162

Jara Construction Roofing. Siding And stucco.

Malvern, PA
4.9
★★★★★
  • Pros icon Free assessment

Services Offered

  • Service icon Window Replacement/Installation

Website: http://www.jaraconstructionchestercounty.com/
Address: 91 Rosemont Ave, Malvern, PA 19355
Phone: (610) 256-6453

Thermal Quality Window & Door Company

Broomall, PA
4.9
★★★★★
  • Pros icon Free assessment
  • Pros icon Price Transparency
  • Pros icon Good Customer Service

Services Offered

  • Service icon Custom Window Designs
  • Service icon Glass Doors
  • Service icon Bay Windows
  • Service icon Vinyl Frames
  • Service icon Window Replacement/Installation

Website: http://www.thermalqualitywindows.com/
Address: 620 Parkway Dr, Broomall, PA 19008
Phone: (610) 325-0788

Graboyes Window & Door

East Norriton, PA
4.8
★★★★★
  • Pros icon Free assessment
  • Pros icon Educational Website
  • Pros icon Price Transparency
  • Pros icon Good Customer Service

Services Offered

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

Website: http://www.graboyeswindows.com/
Address: 48 W Germantown Pike, East Norriton, PA 19401
Phone: (610) 279-3905

M&K Renovations - Basement, Kitchen and Bath Remodeling

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

Services Offered

  • Service icon Window Replacement/Installation

Website: https://mk-renovations.com/
Address: 397 Lancaster Ave, Malvern, PA 19355
Phone: (610) 638-6794

Beatty Lumber & Millwork Company

Upper Darby, PA
4.8
★★★★★
  • Pros icon Good Customer Service
  • Pros icon Free assessment
  • Pros icon Educational Website

Services Offered

  • Service icon Window Replacement/Installation

Website: http://www.beattylumbercompany.com/
Address: 1835 S State Rd, Upper Darby, PA 19082
Phone: (610) 789-5036

ACRE Windows & Doors

Malvern, PA
4.3
★★★★★
  • Pros icon Free assessment
  • Pros icon Educational Website
  • Pros icon Price Transparency
  • Pros icon Good Customer Service

Services Offered

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

Website: https://acrewindows.com/
Address: 274 Lancaster Ave Suite 203, Malvern, PA 19355
Phone: (610) 569-0694

Alderfer Glass Company

Royersford, PA
4.8
★★★★★
  • Pros icon Free assessment
  • Pros icon Good Customer Service
  • Pros icon Educational Website
  • Pros icon Price Transparency

Services Offered

  • Service icon Glass Showers
  • Service icon Storm/Impact Windows
  • Service icon Glass Doors
  • Service icon Skylights
  • Service icon Glass Repair
  • Service icon Window Replacement/Installation
  • Service icon Energy-Efficient Options
  • Service icon Mirrors
  • Service icon Custom Glass

Website: https://alderferglass.com/
Address: 205 W Ridge Pike, Royersford, PA 19468
Phone: (610) 489-2221

Compass Windows and Door

Media, PA
4.6
★★★★★
  • Pros icon Good Customer Service
  • Pros icon Free assessment
  • Pros icon Price Transparency

Services Offered

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

Website: https://www.mycompasswindows.com/
Address: 24 Veterans Sq., Media, PA 19063
Phone: (610) 744-2526

Chapman Windows Doors & Siding

West Chester, PA
4.9
★★★★★
  • Pros icon Educational Website
  • Pros icon Good Customer Service
  • Pros icon Price Transparency
  • Pros icon Free assessment
  • Pros icon Timely Service

Services Offered

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

Website: http://www.chapmanwindowsdoors.com/
Address: 882 S Matlack St STE G, West Chester, PA 19382
Phone: (610) 431-8898

Mr. Handyman of Blue Bell and Doylestown

Montgomeryville, PA
4.9
★★★★★
  • Pros icon Free assessment
  • Pros icon Good Customer Service
  • Pros icon Educational Website
  • Pros icon Price Transparency

Services Offered

  • Service icon Window Repair
  • Service icon Window Replacement/Installation

Website: https://www.mrhandyman.com/blue-bell-doylestown/
Address: 587 Bethlehem Pike Ste 1100, Montgomeryville, PA 18936
Phone: (267) 551-6600

Southwest Vinyl Windows

Lansdowne, PA
4.3
★★★★★
  • Pros icon Good Customer Service
  • Pros icon Educational Website
  • Pros icon Free assessment
  • Pros icon Price Transparency

Services Offered

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

Website: https://southwestvinylwindows.com/
Address: 6250 Baltimore Ave #7, Lansdowne, PA 19050
Phone: (610) 626-8826

Rlc painting and building maintenance

Havertown, PA
3.3
★★★★★
  • Pros icon Price Transparency
  • Pros icon Good Customer Service
  • Pros icon Free assessment
  • Pros icon Educational Website

Services Offered

  • Service icon Window Replacement/Installation

Website: https://www.rlcpaintersnmorepa.com/
Address: 41 W Manoa Rd, Havertown, PA 19083
Phone: (610) 803-4150
King of Prussia Window Cost Calculator

Calculate how much you can expect to pay for window installation and replacement in King of Prussia, PA 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 King of Prussia Saves You Money

By upgrading to energy-efficient windows, you and your family can benefit in several ways, such as:

  • Decrease your carbon footprint: In King of Prussia, you can reduce your indirect greenhouse gas emissions by about 286 pounds per year once you install energy-efficient windows.
  • Save money on electricity bills: The Department of Energy estimates that heat gained or lost via windows makes up about 25-30% of energy use in your home. Switching to energy-efficient windows can help reduce that amount, which helps you save $312 a year on your bills.
  • Protect your valuables: Many energy-efficient windows have low-emissivity coatings, which filter out damaging UV rays, preventing fading of your furniture, carpet and other valuables.
  • Protect your investment: If your home is on the older side, your windows are most likely outdated. Updating your windows can make your home more comfortable and also help increase the value of your home if you decide to sell.

Estimated Cost of Window Replacement in King of Prussia

When researching window installation, each company offers varying services and costs. Let’s go over some average costs and services.

How Much Do New Windows Cost?

Generally, King of Prussia homeowners can anticipate their window replacements to range from $250 to $1,200. The average cost sits at approximately $600. This is because of the fact that window installations are based on several factors specific to your home, such as the size, material and number of windows you need to replace, as well as the location of your property.

It’s important to keep in mind that windows with the best efficiency may cost more initially but can save you hundreds of dollars via returns on your energy bills. Investing in Energy Star certified windows can save King of Prussia homeowners $312+ a year when replacing single-pane windows.

Another factor that affects the overall cost is the material you select for your frame. Aluminum frames are generally the least expensive and are sturdy and light, but they provide poor insulation. On the other hand, wood frames are the most expensive, as they are aesthetically pleasing and offer decent insulation. Fiberglass and vinyl frames provide good insulation as well and cost somewhere between the other two.

What Services do Window Installers Offer?

The first step when considering a window installation is to clarify whether you need a full-frame or pocket installation.

A full-frame installation replaces the entire window, such as the windowsill, frame, trim and the window panes. As this kind of installation requires more time and labor, it will be more expensive than a pocket installation. Pocket installations (or retrofits) involve installing a new window within its existing frame, which makes pocket installations more simple and affordable. However, if the frame has any rot or deterioration, you should opt for a full-frame installation instead.

Your window replacement company will be able to help you decide what’s best for your needs. In King of Prussia, the decision will mostly be based on the age of your home and if there’s any moisture damage. Wood can decay if it’s not maintained properly over the years, so it’s good to have a professional check your frames and window sills.

Best Availability

Renewal by Andersen

★★★★★
4.5
  • Great industry reputation
  • Member of US Green Building Council
  • Manufactures products in-house
Buy One Window, Get One 40% OFF
Get Estimate

Best Energy-Efficient Features

Champion

★★★★★
4.5
  • Many years of experience
  • Low prices relative to competitors
  • Limetime warranty
Buy 2 Windows, Get 2 Free
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 King of Prussia

In our search to make your home improvements easier and more eco-friendly in King of Prussia, EcoWatch chose the above companies as the top window installation companies in the city. We’ve decided to assess the top window installation companies in King of Prussia mainly based on their energy efficient offerings, as it’s the most sustainable option and the best one for homeowners. Energy-efficient windows have been shown to lower energy bills by hundreds of dollars. Along with energy efficiency, our rating methodology takes the following factors into consideration:

Service Area

Since this is a guide for King of Prussia, we only included companies that provide services to the city. There are other reputable providers that didn’t make the cut because of the low odds that they would serve the average homeowner in King of Prussia.

Work Quality

When picking new windows, the quality and range of services can often play just as important of a role in overall efficiency and performance as the brand of window you get. We do give window installers more points if they offer high-quality products, but we also consider workmanship as reflected in customer feedback.

Customer Reviews

Another self-explanatory yet super important review factor is customer feedback. If the majority of customers don’t have good things to say about their service from a certain company, it won’t be featured on EcoWatch.

Cost

Cheaper windows certainly don’t mean better windows, but we know many of our readers want to keep costs low when possible. When analyzing providers’ prices, we awarded higher scores to companies with reasonable prices and accessible financing rather than “cheaper” services.

Warranty

As discussed previously, windows are a sizable investment, so you’ll want to make sure that investment is protected. Window installation companies that have lengthy warranties for products, parts and installation (aka workmanship) rank higher with EcoWatch.

Years of Experience

Due to King of Prussia’s climate, homeowners will want to mitigate low efficiency, water damage and rot. We factored in local experience to reflect the ability of King of Prussia window companies to prepare homes for the climate. If a company has less than 10 years of experience, it loses points in this category.

King of Prussia, PA Window Replacement FAQs

What is the typical cost to install windows in a home?

The national average cost to replace a window is about $600 but can range between $200 and $1,200, depending on several factors. The price is generally dependent on the type and material of the window, the location of your property and the size of the window. Also, keep in mind that energy-efficient windows may cost more initially but can save you a decent amount of money a year in energy bills.

What type of window is the most energy-efficient?

Generally, double-pane windows are more efficient than single-pane windows and windows that don’t open are more efficient than windows that do. If you want to be sure you’re getting the most energy-efficient windows, look for models that have the blue Energy Star certification attached to them — they’re certified energy-efficient by the U.S. Department of Energy.

Can you install your own windows?

Although it is possible to install your own windows, doing so requires a lot of time and experience with home improvement projects. Using a window installation company can help guarantee that the job is done properly and that you won’t have to spend the time and effort to do it yourself.

How do you know it’s 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 should probably be replaced. Apart from that, if your windows have any damage on them, or they have become difficult to open or close, they may be in need of replacement.

Should I replace all my windows at the same time?

If your windows are greater than 20 years old, you probably need to replace all of them. At that point, they are typically less efficient, leakier and/or more damaged than new windows. Doing your windows all at the same time will involve less paperwork and less stress.