How long do windows last?
It depends on the frame — and then it depends on the glass, which runs a shorter clock than any frame on this page. InterNACHI's baseline gives vinyl and fiberglass 20 to 40 years, wood 30+, aluminum-clad 15 to 20, and double-pane glass just 8 to 20. The warranty paper under each material splits along the same seam: one term for the sealed glass unit, a shorter one for everything that is not glass, and a definition of "Lifetime" worth reading before leaning on it.
Updated
Every material on one 60-year axis
Soft band: typical service-life range. Solid bar: the published warranty term. The difference between their right-hand ends is the story.
The numbers, with their sources
| Material | Service life | Warranty term | Source tier |
|---|---|---|---|
| Vinyl windows | 20–40 yrs | “Lifetime” limited, non-transferable, conditional | Tier 3 · baseline chart (undated) |
| Wood windows | 30+ yrs | “Lifetime” limited, non-transferable, conditional | Tier 3 · baseline chart (undated) |
| Fiberglass windows | 20–40 yrs | 20-year limited, transferable, conditional | Tier 3 · baseline chart (undated) |
| Aluminum-clad wood windows | 15–20 yrs | 20-year limited, transferable, conditional | Tier 3 · baseline chart (undated) |
Two patterns run through the grid. First, every one of these warranties is really two warranties — glass and not-glass — and twenty years on the sealed unit against ten on everything else is the shape the industry has settled on. Fogging between the panes is a claim against the first number; a latch that will not catch is a claim against the second, and the two rarely run out together. Second, "Lifetime" on a window is the term that ends soonest for whoever buys the house next: on the vinyl and wood pages it means only as long as the original buyer lives there, and it converts on the closing date into a ten-year term counted from the original purchase. The two plain 20-year terms here, Marvin's and Andersen's, are the ones that actually travel with the property.