Repair or Replace?
How Bay Area Homeowners Should Decide

Most contractors will push you toward full window replacement. That is how they make more money. The honest answer is that repair is often the right call, and knowing which situation calls for which approach can save you several thousand dollars.

Here is a practical framework for deciding what your windows actually need, based on what we see in Bay Area homes every week.

When Repair Makes Sense

Drafts and air infiltration

If your windows feel drafty, the problem is often the weatherstripping or the seal between the window and the wall, not the window itself. Replacing weatherstripping costs $50–$150 per window and can dramatically improve comfort. Re-caulking the perimeter costs even less and is something homeowners can do themselves. Do not let a contractor convince you to replace a structurally sound window because it has a draft.

Sticking, binding, or hard to open sashes

Wood windows stick when they absorb moisture and swell. This is usually repairable: sanding the sash, planing the contact points, and applying a fresh coat of paint that seals the wood can restore operation. Hardware failure (broken sash locks, damaged pulley cords in counterbalanced windows) is also repairable and inexpensive.

Cosmetic paint failure

Peeling paint on a wood window is a maintenance issue, not a structural one. As long as the underlying wood is solid and you address it promptly (paint failure exposes wood to moisture), repainting is all that is needed. A full repaint of a wood window typically costs $100–$250 per window when done by a painter.

Single pane that is otherwise in good condition

Single-pane windows in historic homes are sometimes worth preserving, especially if the frames are solid and the pane is original wavy glass. For landmark properties, preserving original glass is often preferred by the Historic Preservation Commission. For standard homes, the energy case for replacement is stronger (see below), but a sound single-pane window with good weatherstripping and interior insulating treatments (interior cellular shades, for example) can perform adequately.

When Replacement Is the Right Call

Failed double-pane seal (foggy glass)

When you see condensation or fogging between the two panes of a double-pane window, the seal has failed and the insulating gas (argon or krypton) has leaked out. The window now provides no better insulation than a single pane. You cannot repair a failed seal: the insulating glass unit (IGU) must be replaced. At that point, you are often paying 60–80% of what a new window would cost anyway, which makes full replacement worth considering, especially if the frame is more than 15 years old.

Rotted wood frames or sills

Wood rot is the most common reason for window replacement in Bay Area homes. When it is localized to the sill and caught early, it can sometimes be repaired with epoxy wood filler. But when rot has progressed into the frame members or the rough framing in the wall, repair is not practical. The rot will spread, and a new window in a compromised opening will fail prematurely as well. Full replacement (including replacing any rotted rough framing) is the correct approach.

Aluminum single-pane windows with persistent condensation

Original aluminum windows from the 1950s–1980s are thermal bridges: the aluminum frame conducts cold directly from outside to inside. This creates persistent condensation on the interior frame and glass edge, which over time damages sills, paint, and drywall. There is no repair for this: aluminum's thermal conductivity is inherent to the material. Replacement with a thermally broken window (vinyl, fiberglass, or modern aluminum with a thermal break) solves the problem.

Single-pane windows in main living areas

In California, electricity and gas are expensive. A single-pane window loses heat at roughly twice the rate of a double-pane window. The average SF home with single-pane windows spends an estimated $300–$500 more per year on heating than it would with double-pane replacements. Over a 15-year period, that is $4,500–$7,500 in extra utility costs, often more than the cost of replacement, especially when you factor in the federal Energy Star tax credit.

The Cost Comparison

The Decision Rule

Here is a simple framework we give homeowners: if the repair cost is less than 40% of the replacement cost and the repaired window will function well for at least 5 years, repair it. If the repair cost approaches or exceeds 50% of replacement, or if the underlying window has other issues that will require additional repairs in the next few years, replacement is the better investment.

For windows with failed seals, rotted frames, or aluminum frames causing condensation, replacement is almost always the better call regardless of the math, because the underlying problem cannot be permanently fixed.