Serious Energy Savings With Passive House Design

Enlarge Image Image Gallery This Sonoma, Calif., house was remodeled to the Passive House standard and is now incredibly energy efficient.  PHOTO: NED BONZI

Chances are you’ve already given some thought to energy efficiency at home. You may even live in an Energy Star home — this label is the Environmental Protection Agency’s standard for energy-efficient houses. But as more people realize the value of saving energy at home and having a smaller carbon footprint, some green builders are raising the bar. Enter the Passive House standard.

For example, an Energy Star home is already 20 to 30 percent more efficient than typical building code standards. In contrast, a certified Passive House will use an estimated 90 to 95 percent less energy for heating and cooling and 60 to 70 percent less overall energy than a typical code-built home. Although some of the elements of Passive House design add to the cost of the home (think super-efficient windows), that investment pays off through ultra-low energy bills over the life of the home.

Not to be confused with passive solar — a set of design principles focused primarily on capturing heat from the sun — the Passive House standard focuses on the house as a complete, airtight, highly insulated system that uses a very low level of energy per square foot while also improving the home’s indoor air quality. As Katrin Klingenberg, executive director of the Passive House Institute U.S. (PHIUS) says, “Passive House is strictly an energy metric and performance-based certification that works complementary to all other sustainable rating systems already in the marketplace.”

Another exciting thing about the Passive House standard is that it can be applied to existing homes as well as new construction. Certified Passive House consultant Graham Irwin of Essential Habitat recently completed the first Passive House certified retrofit in California (see photo). Retrofitting an older home to meet these high energy standards is no small task, Irwin says. “A Passive House retrofit is a significant and comprehensive lifetime upgrade to the performance and quality of a home.”

Passive House Principles

The Passive House concept was introduced in 1988 by German physicist Wolfgang Feist and Swedish professor Bo Adamson. Feist founded the Passive House Institute in Germany in 1996. The U.S. branch of this organization is PHIUS in Urbana, Ill., which was authorized to certify projects and train Passive House consultants in 2008. Worldwide, there are about 15,000 buildings certified to the Passive House standard, but only about a dozen in the United States, where Passive House is just beginning to catch on.