How often should you replace windows?
Updated July 2026
Most windows last 15–30 years before they are worth replacing, and the windows themselves tell you when: persistent fogging or condensation between the panes, drafts you can feel with a hand, sashes that stick or will not lock, and rot in wood frames. Vinyl and well-kept wood reach 20–30 years, aluminum nearer 15–20. Budget $400–1,000 per window installed, more for large or custom units, and expect a whole-house project to land around $8,000–25,000.
What changes the interval
| Your situation | Interval | Why |
|---|---|---|
| Vinyl double-pane | 20–30 years | Low-maintenance frames outlast their insulated glass seals |
| Wood windows, kept painted | 20–30+ years | Wood lasts generations if you never let water sit on it |
| Aluminum frames | 15–20 years | Metal conducts heat and cold, so they age and lose efficiency sooner |
| Fiberglass or composite | 30+ years | Stable frames that resist warping and hold seals the longest |
| Fogging between the panes | Replace the sash or unit | The seal has failed and the insulating gas has leaked out |
| Single-pane originals | Replace for the energy | One pane of glass loses far more heat than a modern unit |
The cost of skipping it
What skipping it costs: the U.S. Department of Energy attributes roughly 25–30% of a home's heating and cooling energy to heat gained and lost through windows, and drafty single-pane or fog-filled failed units are the worst offenders, quietly padding every utility bill. Beyond comfort and cost, rotting frames let water into the wall. New windows run $400–1,000 each; you can spread the project over several years, doing the worst rooms first. Estimate a phased plan in the cost calculator.
How to do it (Pro installation; measuring and planning are DIY)
- On a cold or windy day, run your hand around each window edge to find drafts, then check for interior condensation.
- Look between the panes: a permanent haze or water droplets means the insulated glass seal has failed.
- Try each sash. It should open, close, and lock smoothly; sticking or warping points to an aging frame.
- Press the wood sill and frame for soft, rotted spots, especially under the corners where water collects.
- Rank the windows worst to best so you can replace the leakiest rooms first if you are phasing the cost.
- Get several quotes and compare U-factor and air-leakage ratings, not just price, before committing.
Knowing the interval is the easy half. OnOtto reminds you at the right interval, and it won't let you snooze it into next year. Tasks persist until they're done, and completing window replacements schedules the next one automatically.
Put this on autopilot, free for 30 daysFrequently asked questions
Can I just reseal a foggy window instead of replacing it?
Fogging means the insulated glass unit lost its seal and its inert gas, and no exterior caulking fixes that. Your options are replacing just the glass unit (the IGU) if the frame is sound, often $150–400 per sash, or replacing the whole window. Defogging services that drill and vent the unit exist, but they restore clarity, not the insulating value, so most owners swap the glass or the window.
Are new windows really worth the money in energy savings?
Energy savings alone rarely pay back the full cost quickly, especially replacing decent double-pane units. Where it makes sense is upgrading from single-pane or failed, foggy units, or when you value the comfort, quiet, and looks. With windows responsible for a quarter to a third of heating and cooling energy, the leakiest originals are the ones that actually move the bill. Phasing the worst rooms first spreads the cost.
Should I repair old wood windows or replace them?
Depends on condition and character. Solid old-growth wood windows can be reglazed, re-sealed, and weatherstripped for a fraction of replacement, and paired with a storm window they perform surprisingly well. If the frames are rotted, out of square, or you want modern low-E glass and easy operation, replacement wins. Reserving the whole $400–1,000-per-window budget is only necessary once repair stops being viable.
How do drafts and failed frames connect to the rest of the house?
A drafty window is often a caulk-and-seal problem before it is a replacement problem, so start by resealing the frames. Water getting past failed frames also feeds wall and foundation issues below. Tracking window age and condition alongside the rest of your exterior in OnOtto keeps a slow-failing seal from becoming rot you find years too late.