How Long Do Windows Last?

Lifespan by Frame Material

Vinyl (20–40 years): The most common replacement window in America. Quality is the whole story: budget vinyl with thin walls and welded corners that flex can warp, stick, and fail seals inside 20 years, while heavier premium frames run 30–40. Heat is vinyl's enemy — dark-colored vinyl on sun-baked elevations ages fastest.

Wood (30+ years): Wood frames have no inherent expiration date — there are 100-year-old wood windows still operating — but they only reach old age if the paint film and glazing are maintained. Rot starts at the sill and lower sash rail where water sits, and unmaintained wood windows can fail in 15 years while maintained ones sail past 40.

Aluminum (20–30 years): Structurally tough and slim-framed, but aluminum conducts heat so well that older non-thermally-broken frames sweat with condensation in cold climates, which corrodes the frame and rots surrounding trim. In mild coastal-free climates they last decades; their thermal performance usually makes them obsolete before their structure gives out.

Fiberglass (30–50 years): The durability champion. Fiberglass expands and contracts at nearly the same rate as glass, so the constant thermal cycling that fatigues vinyl and stresses seals barely affects it. The frame will almost certainly outlive the insulated glass unit inside it.

Note that last table row: the insulated glass unit (IGU) — the sealed double- or triple-pane sandwich — has its own 15–25 year lifespan regardless of frame material. That's why "how long do windows last" really has two answers: frames last decades, but the glass seal is usually the first thing to die.

Signs Windows Are Done

• Condensation between the panes: Fog, haze, or water droplets trapped inside the double glazing — not on the interior or exterior surface — means the perimeter seal has failed and the insulating gas is gone. Condensation on the room-side of the glass is a humidity issue, not a window failure; between the panes, it's terminal for that glass unit.
• Persistent drafts: If you feel air movement with the window locked, the weatherstripping is shot or the sash no longer squares to the frame. Weatherstripping is fixable; a racked frame usually isn't.
• Hard operation: Windows that stick, won't stay open, or need force to lock have warped sashes, failed balances, or a shifted frame. Failed balance springs are a cheap repair — a warped vinyl sash is not.
• Soft or rotted wood: Probe sills and lower rails with a screwdriver. Small rot spots can be dug out and filled with epoxy; rot that has reached the joints or the frame means the window is structurally done.
• Outside noise getting louder: Windows that suddenly seem to block less sound have lost seal integrity or gas fill. It's the same failure as drafts and fogging, arriving through your ears first.

Repair Options First

Full replacement is the most heavily marketed answer and frequently the wrong first move. Much cheaper fixes handle a surprising share of "failing" windows:

• Replace just the glass unit: A fogged IGU can be swapped for a new sealed unit within the existing sash for a fraction of full replacement cost. If the frame is sound and you like the window, this is the highest-value repair on the list.
• Sash replacement kits: Several manufacturers sell sash-only kits that reuse the existing frame — new operating parts and glass without touching siding, trim, or drywall. Ideal when frames are square and sound but sashes are worn or fogged.
• Weatherstripping and hardware: New weatherstripping, sash locks, and balance springs cost little and cure most drafts and operation problems. An afternoon and a hardware-store bag of parts can transform a drafty window.
• Epoxy repair for wood: Localized sill rot can be excavated and rebuilt with wood epoxy, then primed and painted. Keeping that paint film intact afterward is what makes the repair stick — our exterior paint calculator covers the trim and sash paint for the whole house.

Replacement Reality

When a window truly is done, expect $300–$1,200+ per window installed — budget vinyl inserts at the low end, wood-clad or fiberglass full-frame replacements at the high end, with large or specialty shapes going higher still. A whole-house replacement is a five-figure project for most homes.

Here's the honest part the window ads skip: energy savings rarely pay for replacement windows on their own. New windows typically trim heating and cooling bills 10–15%, which against a five-figure install price is a payback measured in decades. The real reasons to replace are comfort (no more drafts and cold spots), stopping active rot before it spreads into the wall, function, and looks — those are legitimate and often worth the money, but go in with clear eyes. If energy ROI is your goal, attic insulation delivers far more savings per dollar than glass ever will.

Windows also rarely fail alone. If your siding is from the same era, replacing both together lets the installer flash the openings properly and saves mobilization costs — see our siding cost guide and our companion page on how long siding lasts to check whether the whole exterior is due.