Stop home energy dollars from leaking out your walls

Published 8:30 am Wednesday, June 9, 2010

As home heating and cooling costs soar, your energy dollars literally might be going out the window — and the walls. Small and not-so-small air leaks through covered walls, floors, ceilings and normal openings such as windows and doors can add up to big losses. While retrofitting older homes with weather stripping, insulation and caulk helps seal air leaks, for new homes and additions, building tight walls can prevent air from escaping.

When building a new home, buyers are often aware of common heating and cooling problem areas, such as windows and doors. Many will ask their builder about double- or triple-pane windows, insulated doors and the quality of insulation, without considering the impact of wall construction on home energy efficiency.

“Energy efficient construction should address air, moisture and thermal movement through walls, as well as floors, ceiling and roof,” said Rob Brooks, green buildings program director for iLevel by Weyerhaeuser. “The quality of framing materials along with the use of spray sealants or housewrap has a large impact on how much air leaks into a house through the exterior envelope, which shields the house from weather. Plus, the spacing and depth of studs and other framing members directly influences the volume of insulation and how effectively it does its job. It’s important to get insulation into all the nooks and crannies such as corners, around windows, soffits and over the outside wall up in the attic space. These issues need to be addressed during construction. It’s very difficult and costly to try to fix them after a home is built.”

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Building codes increasingly call for tight construction, yet many modern homes are built with decades-old framing practices that can leave substantial gaps where air can leak into or out of the house. For example, wall studs and floor joists placed at unmatched intervals, single studs at corners, and window openings with multiple, rather than single-piece members, can leave voids that are difficult to reach with insulation. As with gaps under improperly sealed doors, these un-insulated openings provide a path for air to leak from the home. Furnaces and air conditioners must make up the difference to maintain a comfortable indoor temperature.

“The good news is that advanced framing techniques for a tight home are simple and cost effective,” said Brooks. “It’s a matter of educating builders on the latest framing methods and design software that makes the best use of pre-planning.”

Advanced framing techniques can increase the overall insulating properties of a completed wall by up to 58 percent and allow for 86 percent greater insulation volume when comparing a 2-by-4 to a 2-by-6 wall with the same type of insulation. At the same time, less wood is needed because the larger 2-by-6 studs are spaced farther apart. The result is walls that block heat and cold better, use fewer materials and are stronger than those built using conventional practices.

“More buyers are interested in green or energy efficient homes,” added Brooks. “Framing methods that aid energy efficiency not only are environmentally responsible, they can also help homeowners save money.”