Choosing replacement windows comes down to how each one opens, what the frame is made of, and how it goes into the wall. Make those calls in that order, room by room, and the rest gets a lot easier.
Start with what each room needs
Walk the house before you look at a single brochure. For each window, jot down:
- Whether you ever open it, and how often.
- Whether it's over a sink or a counter, where reaching up to lift a sash is awkward.
- Whether it's upstairs, where cleaning the outside of the glass is a chore.
- What's outside it. A view you want to keep clear calls for something different than a neighbor's wall or a busy street.
The common window types
Double-hung and single-hung
This is probably the window you grew up with. Two sashes stack one above the other. On a double-hung, both slide, and most tilt inward so you can clean the outside glass from inside the room. On a single-hung, only the bottom sash moves. Either one suits almost any style of house, from a brick ranch to a two-story colonial.
Casement
A casement is hinged on one side and cranks outward. Because the sash presses against the frame when it closes, casements tend to seal tight. They work well over a kitchen sink, where turning a crank beats leaning over to lift a sash, and they catch a side breeze nicely. The crank is one more part that can wear out, and a window that swings out doesn't belong beside a deck or a walkway where people pass.
Sliders
Sliders have sashes that move sideways on a track. They're simple and easy to use, and you'll see them in basements, in wide spaces and on a lot of mid-century houses. Keep the track clean, because that's where they give trouble.
Picture windows
A picture window is fixed glass that doesn't open at all. You get the most glass and the cleanest look, with nothing to wear out. They're often paired with casements or double-hungs on either side so the room still gets air.
Frames: vinyl, fiberglass or wood-clad
| Frame | What it does well | What to watch for |
|---|---|---|
| Vinyl | Lower price, no painting, shrugs off moisture | Not meant to be painted, thicker frames mean a little less glass, fewer color choices |
| Fiberglass | Stays stiff and steady through heat and cold, can be painted, slimmer frames | Costs more than vinyl |
| Wood-clad | Real wood inside, aluminum or vinyl cladding outside | Costs more again, and the inside wood needs care where condensation sits |
| Aluminum | Slim and strong | Passes heat and cold through easily, so it's a poor fit for most houses |
For most houses, the decision is between vinyl and fiberglass. Wood-clad is for the room where you want real wood on the inside and you're willing to look after it.
Insert or full-frame?
This is the decision a lot of people don't know they're making.
An insert, sometimes called a pocket replacement, goes inside your existing window frame. The old sashes come out, the frame stays, and the replacement window slides in and gets sealed. The trim inside and out usually stays put. It's faster and cheaper. The trade-off is a little less glass, since you're fitting a frame inside a frame, and you're trusting the old frame to be sound.
A full-frame replacement takes everything out down to the studs, trim included. That lets you see whether water has been getting into the wall, redo the flashing around the window, and fill the gaps with insulation. It costs more and means fresh trim inside and out.
My opinion: if the old frames are soft anywhere, or you see water stains on the wall under a window, go full-frame. An insert over rotten wood just hides the problem for a while. If the frames are solid and dry, an insert is a perfectly good choice.
Glass and the energy label
Look for the label from the National Fenestration Rating Council on the glass. It lists the U-factor, which is how well the window holds heat in, and the solar heat gain coefficient, which is how much of the sun's heat it lets through. What replacement windows save on a power bill explains what both numbers mean for a house here.
Keep the front of the house consistent
Mixing window styles on one side of the house can look odd from the street. Keep the grille pattern, the strips that divide the glass into panes, the same across the front, and match the frame color to the trim. If you have an HOA, check its rules on frame color and grilles before you order.
How to compare two quotes
Ask each company to price the same thing:
- The same window line and frame material.
- Insert or full-frame, spelled out window by window.
- What happens if they find rot once the old window is out, and what that costs.
- Trim, caulk and hauling away the old windows.
- Who backs the window (usually the maker) and who backs the installation (the company), in writing.
Our windows and doors page covers what we install, and the products page lists the window lines we carry.
Questions
Can I replace windows a few at a time?
Yes. It often costs more per window than doing the whole house at once, but it's a fine way to start with the worst ones, like the ones with fogged glass or the ones that face the afternoon sun.
Does a fogged window mean I need a whole new window?
Fog between the panes means the seal has failed. Sometimes just the glass can be swapped. On older, cheaper windows, replacing the whole thing often makes more sense.
