If you're considering replacement windows, do the math to find out how cost-effective new units would be. One way is by completing a home energy audit. Whether you hire a professional or try the DIY route, this energy efficiency checkup for your home will give you a sense of where the major energy-loss areas are and how serious they are.
It's essential to get a good read on where the thermal transmission problems are in your home before you do a full replacement-window renovation. A whole-house window makeover might not be necessary when your real problems might be solved by a tube of caulk, some weatherstripping or a few storm windows.
Situations where you may need a window replacement:
• Your windows have single-pane glass or temperature-conductive frames and sashes. Homes with cheap, poorly-performing windows can almost always benefit from window replacement.
• Your windows are in poor condition. Beyond efficiency concerns, windows in poor condition can contribute to water leaks, humidity problems in the home and even pest infestations. Cracked windowpanes, non-operational windows and rotting frames, sashes or sills on wood windows are all good reasons to consider replacement.
• Your windows pose safety problems. Windows that don't open or shut completely or that are weak or loose because of improper maintenance or damage are good candidates for replacement. And if your home has upper-floor rooms with windows that don't open, consider replacing them with operable windows and placing an easy-to-use fire ladder in the room so the windows can serve as exits in case of emergency.
New windows are available in wood, aluminum, vinyl, and fiberglass.
Wood frames are a common choice for remodels and can be bought to match existing windows if you aren't planning on replacing all of them.
Wood window sashes can be replaced to update a drafty window, but they require a bit more maintenance. Still, they offer a classic look, so for an older home to retain it's original style, wood windows are often the only option.
Clad-frame windows feature an aluminum or vinyl shell. They are used most frequently in new construction and are attached with nailing flanges that fit underneath the siding material. The quality of clad can range from roll-form aluminum, the thickness of a soda can, to extruded aluminum.
Vinyl clad windows are available in a variety of colors, and they don't require as much maintenance as wood windows (and don't need painting). They don't look quite as nice as wood windows, but they're cheaper, and insulate almost as well. Fiberglass composite windows are stronger than vinyl, but are slightly more expensive.