Most windows last somewhere between 15 and 40 years, depending on the frame material and how well they’re maintained. InterNACHI, the home inspectors’ association, puts aluminum windows at 15 to 20 years, vinyl and fiberglass at 20 to 40, and wood at 30 years or more.
In a hot, humid place like New Orleans, the parts that wear out first are usually the seals, caulk and finishes rather than the frame itself. Keep those up and a window can reach the long end of its range. Let them go and water does the rest.
At TurnKey Window we repair and replace windows around the New Orleans area. If you’re not sure how much life your windows have left, ask us to take a look or call (504) 226-6201.
Key takeaways
- InterNACHI’s chart lists aluminum windows at 15 to 20 years, vinyl and fiberglass at 20 to 40 years, and wood at 30+ years.
- Double-pane glass units are listed at 8 to 20 years, so the glass seal can fail before the frame does.
- Caulking is listed at 5 to 10 years, and InterNACHI notes that high humidity can shorten the life of caulks and paints.
- Wood decay fungi grow best between 24°C and 32°C (about 75°F to 90°F) and need wood wet above about 30 percent moisture, per the USDA Forest Products Laboratory.
- InterNACHI’s chart says life expectancy varies with weather, installation, maintenance and material quality, so upkeep matters as much as the label.
Window lifespan by material
InterNACHI’s Standard Estimated Life Expectancy Chart for Homes is written for consumers, inspectors and the professionals who advise them. The chart itself says its figures assume regular recommended maintenance and normal wear, not extreme weather, neglect or abuse.
| Component | Estimated life (InterNACHI) |
|---|---|
| Aluminum or aluminum-clad windows | 15 to 20 years |
| Vinyl or fiberglass windows | 20 to 40 years |
| Wood windows | 30+ years |
| Double-pane glass units | 8 to 20 years |
| Window glazing | 10+ years |
| Caulking | 5 to 10 years |
| Sealants | 8 years |
InterNACHI adds that life expectancy varies with usage, weather, installation, maintenance and material quality, and that the list is a guideline rather than a guarantee. Treat the ranges as a starting point for your own house.
Vinyl windows
Vinyl frames aren’t food for decay fungi, which the Forest Products Laboratory describes as organisms that use wood as food. InterNACHI’s range of 20 to 40 years is still wide, and its chart points to installation and material quality as two of the reasons lifespans vary.
On vinyl, the parts to watch are the moving and sealed ones: balances, locks, weatherstripping and the insulated glass. SoftLite’s warranty summary, for example, covers vinyl frames, balances and locks for as long as the original purchaser owns and lives in the home.
Finishes are different. The same summary covers painted or factory-coated vinyl exteriors for 10 years against peeling, cracking or blistering. InterNACHI’s chart separately notes that UV rays from sunshine can shorten paint life.
Wood windows
Wood can outlast everything else when it’s kept dry and painted. The New Orleans HDLC’s Guidelines for Windows and Doors say the timber used in historic windows can last substantially longer than replacement units, and that salvaged and repaired windows will often outlast new ones.
The weak points are the sill, the bottom rail of the sash and any joint where water can sit. That’s where paint fails first and where rot starts.
Aluminum windows
Aluminum sits at the short end of InterNACHI’s chart at 15 to 20 years, the same range it gives aluminum-clad units. The chart doesn’t break down which part wears out first, so look closely at the seals and weatherstripping on older aluminum windows.
If you’re weighing aluminum against other frames for a new project, compare the warranty terms on seals and finishes as well as the frame.
Fiberglass windows
InterNACHI groups fiberglass with vinyl at 20 to 40 years. As with vinyl, the glass unit and hardware are the parts to watch.
Why humidity shortens window life
Heat and moisture work on windows in a few specific ways. Knowing them tells you where to look during a yearly check.
Wood decay needs warmth and water
The USDA Forest Products Laboratory’s chapter on the biological properties of wood explains that decay fungi need food, oxygen, the right temperature and moisture. It gives the temperature range as 10°C to 35°C, with an optimum of 24°C to 32°C, which works out to roughly 75°F to 90°F.
New Orleans sits in that optimum from roughly May through September. The National Weather Service’s 1991 to 2020 normals put the average daily temperature at New Orleans International Airport at 77.1°F in May and 84.0°F in August.
The same FPL chapter says decay needs moisture above the fiber saturation point, about 30 percent, and that free water from rain, condensation or ground contact has to be present. Air-dried wood usually stays at 20 percent moisture or less, so decay won’t occur. Keeping water out is the whole game for wood windows.
Caulk, paint and sealants wear faster
InterNACHI’s chart notes that high humidity indoors or outdoors can affect the lifespan of caulks, paints and sealants, and that they should be inspected and maintained seasonally. It also says UV rays from sunshine can short