In this video: Proper installation of new windows is critical to making sure they deliver on their energy efficiency promise.

Installing your windows

If you're installing replacement windows or doors yourself, it's vital to make sure you follow all the rules - if it isn't level or plumb, it won't seal tightly, allowing cold air and damaging water to leak in. Follow the manufacturer's instructions carefully, and take your time - it won't be easy to fix mistakes later.

Before the finishing trim is hung, check all the windows in your home with a carpenter's level and use shims to correct any that might be off-kilter.

After the windows are hung, be sure to add fiberglass or foam insulation in the larger gaps and caulk the edges of the frame and casing. Remember - a gap as small as 1/16th of an inch can let in as much cold air as leaving the window open three inches!

Maintaining your windows

Ongoing maintenance is a must to keep cold air and moisture out. Weatherizing windows is easy and inexpensive. In fact, an investment of $50 in weatherizing supplies can reduce heating costs by two to three times that much!

Another area many homeowners overlook is the window glazing - the putty that secures the glass to the sash. Over time, the glazing can harden, crack and fall off - leaving your window panes loose, drafty and dangerous.

You can purchase window glazing at any hardware or home improvement store. Just chip or scrape off the old glazing, clean the window thoroughly and install the new glazing with a putty knife or caulking gun. Some types of window glazing require a coat of latex paint for a weatherproof seal.

To prevent condensation - and the accompanying mold and mildew - be sure to monitor the humidity level in your home.

More from this category

Buying new windows

Performance label on a window

The style, type of material and what's between the panes can make a big difference in the energy efficiency of your new windows.

learn more

Making older windows more efficient

Dormer window at night

You can make old windows more energy efficient without replacing them. Learn how.

learn more

Reflective window film

Bright sunset

If sunny windows are turning your living spaces into a sauna, reflective window film can bring back the comfort and cut your air conditioning bills.

learn more

Exterior and garage doors

Worker installing a new front door

Improved materials and insulation help new doors stand up to weather and humidity - and keep heat where it belongs.

learn more

Restoring and repairing double hung windows

Man holding up a double hung window

Our expert explains how to restore and repair your double hung windows instead of replacing them.

learn more