If one window is fogged, do I replace all of them?

Not automatically. Replace the failed IGU or that unit if hardware still works. Replace the whole elevation when several units are failing, the frames are chalked or racked, or you want a consistent energy package.

Do lifetime warranties mean they last a lifetime?

No. Read transfer rules, labor coverage, and glass prorating. “Lifetime” often means the original owner and the frame only.

Windows

How Long Do Windows Last?

Quality vinyl or fiberglass windows often last 20–40 years. The sealed glass unit, hardware, and install usually fail before the frame. South-facing sun, coastal air, and skipped caulk shorten the calendar.

8 min read

Frame vs glass vs hardware

A window is three products. Frames can outlive the insulated glass. Balances, locks, and rollers are wear parts. Fog between panes means the IGU seal failed — that unit is no longer insulating as designed.

Vinyl/fiberglass frames: often 20–40 years
Wood that is not maintained: sills can rot in 10–20 years
IGU fogging: common in year 10–25 depending on quality and sun

What ages windows faster

Unblocked west sun, sprinklers hitting the exterior, failed exterior caulk, and a house that was re-sided without reflashing windows all cut life short. Opening a painted-shut window the wrong way breaks hardware.

Dark vinyl in full sun in the Southwest
Ocean salt on unprotected hardware
Interior moisture from baths without fans — condensation rot

Maintenance that actually extends life

Wash weep holes, recaulk exterior joints when they split, keep tracks clear, and fix broken seals in the house envelope so the window is not the only moisture path. Do not paint over vinyl weep holes.

Annual visual check of exterior sealant
Lubricate locks and rollers with the product the maker specifies
Replace failed IGUs when the rest of the window is still sound — if parts are available

Frequently asked questions

If one window is fogged, do I replace all of them?: Not automatically. Replace the failed IGU or that unit if hardware still works. Replace the whole elevation when several units are failing, the frames are chalked or racked, or you want a consistent energy package.
Do lifetime warranties mean they last a lifetime?: No. Read transfer rules, labor coverage, and glass prorating. “Lifetime” often means the original owner and the frame only.