Sure, any one can install a window... as long as they have the proper expertise and credentials. Good windows installed badly by someone who is not an expert, won't deliver the look, comfort, or savings you expect. So in addition to getting multiple bids and detailed contracts, here are some specific tips on choosing an installer:
Seek certification
Many major window manufacturers, like Jantek, train and certify installers on their specific lines. Using the same contractor for purchase and installation can avoid finger-pointing if there is a problem later. Also a certification from a reputable organization such as InstallationMasters™ www.installationmastersusa.com. Of particular importance if your property was built prior to 1978, is that as of April 22, 2010, Federal Law requires all window installation companies to be certified and registered with the U.S. Department of Environmental Protection. For properties built prior to 1978, strict Lead Safe Work Practices must be followed while installing your windows unless a lead test is completed and indicates that lead is not present. Your window installer must also have a signed receipt from you indicating that he gave you the required "Renovate Right" publication prior to beginning work. If your contractor does not seem to know about this or, does not want to comply, he is breaking the law and possibly, so are you. The law does not apply to you if you are installing your own windows.
What's the warranty on the installation?
The manufacturer's warranty covers product defects, but does not cover defects in the installation that may lead to leaks or poor performance of your windows. Make sure that you get a written warranty from your installer that will cover any defects in the installation.
Interview the installer
Go to the window manufacturer's website and read the Installation Instructions for the window you've chosen. Jantek has posted installation instructions for its window models on this website. Ask whether the installer plans to follow them—down to details such as the type,
amount, and placement of flashing/capping, and insulation. If not, he should be able to explain why.
Remember that some changes, or neglecting to follow the manufacturers instructions while installing replacement windows could void the manufacturer's product warranty.
Know what to expect
Any seasoned installer should be able to tell you how long the actuaI task of installing
replacement windows should take. Ask about the installation process. It's better if each new
window is put in immediately after the old one is removed. If one crew removes all the
windows first and another installs, you'll be left with multiple openings for the duration. And be
sure the installer measures each replacement window before he rips out the old one.
Otherwise, you could end up with a boarded-up hole waiting for the right window to arrive.
Mind the little details
If you want to paint after installing replacement windows, have the installer use acrylic-latex
caulk, which is paintable, not silicone. And be sure the window works well before the installer
applies interior trim.