Windows & Doors
Improving the energy efficiency of your existing windows and doors can be more cost-effective than replacing them.
If your existing windows still function—and your goal is to improve efficiency—consider upgrading their weather-stripping and latching hardware first, or adding Low-E storm windows. New replacement windows work well to block drafts, increase comfort, improve egress, reduce solar heat gain, and boost real estate values. But due to their high price, they’re usually less cost-effective than insulating and air-sealing your home or building.
Types of Windows and Glazing
Windows come in single and multiple glazings, double pane or triple pane. Each pane offers an extra, insulating air layer between you and the outdoors. For residential and commercial buildings, window styles include double- and single-hung, awning, casement, and sliders. Materials range from wood to vinyl, fiberglass, PVC, and aluminum. The best way to compare window efficiency is to look at the whole-unit U-value and Solar Heat Gain Coefficient (SHGC). The lower the U-value number, the more efficient the window. A higher SHGC indicates more solar heat gain.
- Additional panes add extra air layers, more insulation
- Low-E window coatings help trap heat inside without impeding light
- Exterior shutters, awnings, and interior blinds provide some insulation against summer heat gain
Types of Exterior Doors
Doors are available in many styles and materials—sliders, French doors, swing-in, swing-out, metal, fiberglass, and wood, among others. Some have windows, and older doors may contain non-tempered glass (which can be a safety issue). Improving doors is a good DIY project for your home or business, starting with simple measures like weather-stripping, door sweeps, storm doors, and striker plate adjustments to eliminate drafts.
Tips for Improving Window Efficiency
To make your windows and doors more efficient, start by fixing some common sources of air leaks: Replace cracked panes and glazing compound, improve weather-stripping, add caulking around window casings, and fill in unused pulley cavities. (Be careful not to caulk the window shut.) Also, check to make sure sash locks are present and well aligned. For older casement windows, replace stripped-out crank mechanisms. Last, consider adding Low-E storm windows.