Here’s our estimate of average life expectancy for several types of windows. You can click on any one of them to go to an article with more info on that window type:

Aluminum - 15 to 30 years, average 20
Double-Pane (Insulated) Glass - 10 to 20 years, average 15
Fiberglass - 20 to 45 years, average 35
Skylight and Light Tube - 8 to 20 years, average 14
Vinyl -  20 to 40 years, average 30
Wood - 20 to 45 years, average 30

    Lifespan is dramatically affected by both maintenance and where the window is located. Here’s a few examples:

•  Pressure washing of insulated windows while cleaning the exterior walls of a home can break the seal between the glass and frame. This releases the inert gas between the panes, eliminates the insulation rating of the window, and allows condensation between the panes of glass to gradually cloud the window. We occasionally see houses where all the double-pane windows have prematurely lost their gas and become clouded shortly after the homeowner tried out his new pressure washer on them. 
• Thermal flexing hot/cold cycles of double-pane windows in direct sun can also shorten their life somewhat, but eventually they all lose their gas and become clouded. One window repair company in our area offers a temporary solution: they remove one of the panes of glass. This solves the problem of cloudiness on the interior surfaces of the glass between the two panes and extends the life of the window, but eliminates any insulation benefit. 
• Landscape sprinklers that spray on a window will reduce its life, especially wood windows. Heavy condensation is also detrimental to windows.
• Poor installation or structural settlement will cause windows to be difficult to operate. The stress on the window frame will also shorten its life.
• The quality of the operating mechanism and how often it is used will affect the life of the window.
• Exposure of the window to sun and rain due to location will also affect lifespan. Windows in direct sun for most of the day and with minimal roof overhang protection will have a shorter life. Skylights are an extreme example of this. Thermal pumping, noted above, is one the multiple exposure variables.

    Windows sometimes last much longer than these estimates with luck and careful maintenance, but end up being replaced for cosmetic reasons. New windows make an older house look fresh. One popular strategy that flip house investors use to increase an older home’s curb appeal is to replace the windows across only the front of a house. 

    Go to our blog post What is the average lifespan of the parts of a house? for rating of other house components. 

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  To learn more about doors and windows, see these other blog posts: 

• What are the signs it's time to replace windows?

• What causes sweating (condensation) on the inside of windows in the winter? 

• Is every exterior door of a house required to have a landing outside? 

• What are the small slots at the bottom of the outside of my window? 

• Why does condensation form on the outside of some windows and not others in the morning? 

• Why is the garage door track a white tube? 

• What is the raised metal plate on the floor under the garage door?

• Why do I have to hold down the button to close the garage door? 

• How can I tell if a window or glass door is safety glass? 

• What are the code requirements for safety tempered glass for doors?• 

• Should a front door swing in or out? 

• What is "low-E" window glass? 

• What does ANSI 297.1 on glass mean?

• Why is a double cylinder deadbolt lock on an exterior door a safety hazard? 

• How can I check my garage door to make sure it is safe?  

• What is an egress window?

• Does a home inspector test all the windows and doors in a home? 

• How difficult is it to change a window to french doors or a sliding glass door?

• How do you determine if a door is left-handed or right-handed?

• Why are window security bars dangerous? 

• What are the common problems you find inspecting windows?

• What is causing a foggy haze on my windows? 

• When is safety glass required for windows at stairs and stair landings?

   Visit our DOORS AND WINDOWS page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.