How long do windows last?

Aluminum and wood frames typically last 15 to 30 years, vinyl 20 to 40 years, and fiberglass 30 to 50 years. Actual life depends heavily on climate exposure and how well the seals were installed.

Is condensation between panes repairable?

Not really. A failed seal means the gas fill that provided insulation has escaped, and the practical fix is replacing the glass unit or the whole window, not resealing it.

Are storm windows a problem for an FHA loan?

They can be, in specific cases, if they’re the only thing standing in for a proper window and an appraiser flags a safety or egress concern. It’s not universal, but it’s worth confirming directly rather than assuming it’s fine.

Do new windows pay for themselves in energy savings?

Rarely on energy savings alone within a reasonable timeframe, at $500 to $1,600 per window installed. They’re a comfort, value and maintenance upgrade first, with energy savings as a secondary benefit, not the primary financial case.

How to Check Windows and Doors When Buying a House

How do you spot a failed window seal?

Look for fog, haze or visible moisture trapped between the panes of a double-pane window. It won't wipe away, because it's on the inside of the sealed unit, not on the glass surface you can reach.

This is easiest to catch on a sunny day or with the light behind the window at an angle. A failed seal isn't dangerous, and the window still functions, but the insulating gas fill between the panes is gone, which means that window is now working closer to single-pane efficiency no matter how new it looks from across the room.

How do you tell single-pane from double-pane glass?

Diagram comparing single-pane glass, a healthy sealed double-pane window, and a double-pane window with a failed seal showing fog trapped between the panes — Single pane, a healthy sealed unit, and a failed seal, the fog is trapped between the panes and won't wipe away.

Look at the edge of the glass where it meets the frame. A double-pane window shows a visible gap between two glass layers and often a metal spacer bar. A single-pane window shows one thin sheet of glass with nothing behind it.

Storm windows aren’t automatically a fix

A house with original single-pane windows and add-on storm windows over top can look updated without actually meeting current standards. In some cases this combination has caused issues with FHA loan approval over egress or safety concerns. It's not a universal rule, but it's worth asking about directly if a house is relying on storms instead of true replacement windows.

What do replacement windows cost?

Expect $500 to $1,600 per window installed, with most landing around $750. A full-house replacement project averages $7,183, typically falling between $3,436 and $11,837 depending on how many windows and what material you choose.

What a window or door finding actually costs, and what it likely means. Prices are national 2026 averages.
What you see	What it means	Typical cost	Verdict
Fog or condensation between the panes of a double-pane window	Seal has failed; the gas fill and insulation value are gone	$500 - $1,600 per window to replace	price
Single-pane windows with add-on storm windows only	Lower efficiency, and can complicate FHA loan approval	Ask about it directly before offering	note
Multiple doors or windows sticking at once	Foundation movement, not individual hardware wear	See the structure guide	walk
Diagonal crack from a window or door frame corner	Foundation-shift signature, not cosmetic damage	See the structure guide	walk
A door that won’t latch or has a visibly uneven gap	Minor hinge/frame wear, or a foundation signal if paired with other doors	$50 - $100 for a simple fix	note

Can old windows affect mortgage eligibility?

It's uncommon but possible, mainly when a window is also serving as required bedroom egress or when an appraiser flags a safety issue tied to storm windows standing in for real ones. This is worth a direct question to your lender if a house you're serious about has clearly original windows.

What door problems signal a bigger issue?

One door that sticks or won't latch cleanly is ordinary wear, fixed for $50 to $100 in most cases. Multiple doors sticking at the same time, especially alongside a diagonal crack running from a door or window frame corner, points at the foundation moving, not the doors themselves.

This is worth checking deliberately rather than noticing by accident. Try every interior and exterior door you pass through during a showing, not just the ones that happen to be open. A pattern across several doors tells you something a single sticky door never will.

Questions buyers ask

How long do windows last?: Aluminum and wood frames typically last 15 to 30 years, vinyl 20 to 40 years, and fiberglass 30 to 50 years. Actual life depends heavily on climate exposure and how well the seals were installed.
Is condensation between panes repairable?: Not really. A failed seal means the gas fill that provided insulation has escaped, and the practical fix is replacing the glass unit or the whole window, not resealing it.
Are storm windows a problem for an FHA loan?: They can be, in specific cases, if they’re the only thing standing in for a proper window and an appraiser flags a safety or egress concern. It’s not universal, but it’s worth confirming directly rather than assuming it’s fine.
Do new windows pay for themselves in energy savings?: Rarely on energy savings alone within a reasonable timeframe, at $500 to $1,600 per window installed. They’re a comfort, value and maintenance upgrade first, with energy savings as a secondary benefit, not the primary financial case.

Related checks

Cost figures: This Old House, Angi and Modernize 2026 window replacement pricing. Door repair costs: Angi and Well Built Florida 2026 guides. Foundation-signature cross-reference shared with the structure guide on this site. Figures are national averages current as of September 2026.