Good windows installed badly won't work or look as good as they should. Improperly installed windows could even end up using more energy, not less. Here's some advice from the experts at Consumer Reports on how to choose a window installer plus the best windows from our window tests.
Seek certification. Some major manufacturers recommend installers specifically trained and certified for their products. Using the same contractor for purchase and installation can avoid finger-pointing if problems occur later. If you have the home center install the windows you buy there, find out how complaints are handled. The home center should be willing to help resolve problems with its contractors to your satisfaction. Look for certification from the American Window and Door Institute or check credentials at InstallationMasters.
Do your due diligence. Even if the installer is certified or manufacturer-trained, you still need to check references and the Better Business Bureau's website for ratings and comments. Ditto for those you find on services such as Angie's List. Ask for the full name and address of the company, how long it has been in business, and proof of insurance carried and licensing if required in your state. Does the company offer a warranty on its work?
Know what to expect. A seasoned installer should tell you about how long the job will take. Ask about the process. It's better if each new window is put in right after the old one is removed. Insist that the installer measure each replacement window before ripping out the old. You don't want a boarded-up hole while you're waiting for the right window to arrive. Think twice about using a contractor who removes all the old windows first and then installs the new windows. If there are any problems, you could be left with lots of holes in your walls for days or weeks.
Focus on details. Get multiple bids and scrutinize them. They should include specifics: window brand, number of windows, their size and type, plus any add-on features. It should also include installation details, such as how the windows will be sealed and insulated. Labor and material costs should be broken out. If you want to paint around the windows, have the contractor use acrylic-latex caulk, which can be painted, and not silicone. And be sure your windows work well before the contractor applies interior trim.
In our tests of wooden, vinyl and fiberglass double-hung and casement windows we found 12 that performed well enough to recommend including four that we named CR Best Buys. Here is the top model of each type we tested.