Q: My windows are old and drafty. What window options should I consider?
A: Upgrading or improving your windows is an important component of your home’s energy efficiency. According to the U.S. Department of Energy, heat gain and loss through windows consumes 25% to 30% of residential heating and cooling energy use.
Start by identifying the kind of windows you have. Are they single pane or double pane? Looking closely at the window’s edge, you can see the number of windowpanes. Are the frames metal, wood or vinyl? Some manufacturers etch the make and model numbers in a corner of the glass, so you can look up the manufacturer for more information.
Single-pane windows and double-pane windows with metal frames are the least energy efficient. The lower the efficiency of your existing windows, the higher the energy savings potential.
Options for improving your windows range from replacement windows to storm windows to budget-friendly repairs.
Several components make windows more efficient. High-quality frame materials insulate and reduce heat transfer. Two or more panes of glass with space in between that is filled with air or gas improve the window’s insulation capability. Warm-edge spacers hold the panes of glass the proper distance apart and help insulate the edges of the panes. Low-emissivity coatings applied to the glass reflect infrared light, keeping the heat in during the winter and out during the summer.
Window efficiency is rated in U-factor and Solar Heat Gain Coefficient. U-factor measures heat transfer through the window, which relates to how well it insulates. The lower the U-factor, the more efficient the window. The SHGC measures how effectively the window blocks heat from the sun.
Replacement and Maintenance
If you want to replace your existing windows, I recommend shopping for Energy Star-certified windows. Energy Star sets specific U-factor and SHGC requirements based on your geography, so you get the best fit for your location. Replacement windows offer other additional benefits, such as improved operability and aesthetics. As with many industries, the window industry has been affected by price increases the past few years.
Storm windows are a lower-cost solution for some homes. Traditional storm windows are made with clear glass. Low- emissivity storm windows have energy savings similar to replacement windows at about a third of the cost.
These windows are mounted to the interior or exterior and are available in operable styles, so you can still open and close your windows. Look for Energy Star-certified models.
If you want to maintain the historic architecture of your existing windows, low-e storm windows are a great option. Some companies can refit your existing window frames with custom double-pane glass and weatherstripping.
As with any home improvement project, get multiple quotes to compare pricing and scope of work. You may find savings with rebates from your electric utility and state, or state or federal tax credits for window upgrade projects.
If new windows or storm windows are not in the budget, your best bet is to maintain existing windows. Keep the paint and caulking on the exterior in good condition to prevent damage from the elements. Caulk around the inside trim, and ensure sash locks are installed properly and seal tightly when locked. There are a variety of weatherstripping types for windows to keep drafts at bay.