Insulate Windows – Lower Energy Costs

The ability to reduce drafts or mitigate the impact of a shining sun through windows can have a major impact on home energy costs:

• 15 to 35 percent of the heat loss experienced in colder climates results from poorly insulated windows.
• In the Sun Belt, the summer sun passes through the windows, increasing the ambient temperatures and forcing air conditioning systems to work harder. Higher electric bills are the likely outcome.

Whether the challenge is heating or cooling related; insulating windows is the solution.

Preparations for Insulating Windows

Before selecting a method of insulation, one should first determine the objective, with temperature regulation being the most obvious and other factors that will drive key decisions:

• Insulation value
• Acceptable trade-offs (i.e. compromise view, block access to the window, or limit the amount of light)
• Seasonal or year-round
• Insulating inside or outside the casings (inside more efficiently reduces airflow)

Cost is also a consideration, again with trade-offs:

• Rubber or foam weather stripping or plastic sheeting are solutions with modest costs
• Spraying or inserting insulation in the jambs, more lasting solutions, will be more expensive
• Aesthetics also cost money – window treatments or thermal shades are more appealing than caulk, foam or vinyl

After narrowing in on these decisions, the last step in preparing to insulate the windows is to take precise measurements of the windowpanes, casings and frames.

Processes and Tools for Insulating Windows

The actual process can vary across a full array of insulation project. The following are some of the basic techniques and tools that will apply regardless of the specifics:

• The less expensive window insulation kits come with a large sheet of plastic film and double-sided adhesive tape. The plastic film is simply mounted, completely covering the window, using the adhesive tape which is stuck around the window frame on all four sides. Any excess film can be cut away with knife or scissors; and a hair dryer can be used to tighten the film and make a wrinkle-free firm seal.
• Drapes can be used as window insulation, provided a tight seal is created. Weights, magnets, Velcro and snaps can be used to prevent air from circulating into the space behind the curtain. This is accomplished by ensuring no space is left between the drapes and the window frame, windowsill or floor.
• Window sashes require the removing of molding that surrounds the window frame followed by fitting a piece of rigid insulating foam into the space between the window jamb and wall and spaying polyurethane into the jamb itself.

Benefits – Lower Energy Costs and Improved Energy Efficiency

As previously noted, windows account for substantial heat loss in cold weather and heat gain in warm weather, thereby contributing significantly to home energy costs. Single-pane windows exist in half of U.S. homes and represent a major contributor to energy inefficiency. Improving insulation will:

• Prevent heat loss, thereby reducing home heating costs and similarly mitigate the impact of the sun, reducing air conditioning costs
• Ensure an even temperature throughout the home
• Allow heated homes to maintain a higher humidity level, better air quality, and lower levels of condensation on the windows
• Decrease fossil fuel use
• Slow down carbon emissions