Passive House design relies on energy-saving windows
When it comes to building a home to the Passive House standard, windows play a major role in achieving the desired energy efficiency.
A certified Passive House is built to meet performance standards while using up to 90 percent less energy for heating and cooling than an average home. To meet that goal, a Passive House is very well insulated and is primarily heated by passive solar gain as well as heat generated from the people and appliances inside. Minimal heating and cooling and a supply of fresh air are provided by an energy-recovery ventilator.
Because the Passive House standard is based on performance, designers and homebuilders are free to make choices to accomplish the final goal.
"The standard doesn't dictate that you use certain windows, it dictates that, when all is said and done, the house is very tight and measurably so with a blower door test and only uses a certain level of energy for heating and cooling," said Mike Knezovich, director of outreach and marketing for Passive House Institute U.S., which administers the Passive House certification program.
The requirements for windows to help a home meet the Passive House standard varies by climate zone, Knezovich said.
"If you're on the west coast and trying to hit the Passive House standards you can probably get away with a really good double-pane window, but if you live in a severe climate where it gets really hot or cold, or both, the true triple-pane Passive House window is critical," he said.
The demand for windows for Passive House construction and remodeling projects is on the rise as homeowners and builders learn more about the standard, said Valerie Jenkins, director of marketing and communications for Serious Materials, a Sunnyvale, Calif.-based maker of high-performance windows.
A passive solar building is designed to take advantage of the climate and how a building is oriented toward the sun. With the right windows the building benefits from free heating in winter, and cooling by rejecting solar heat in the summer, Jenkins noted.
"Windows are important part of meeting the standard because of the insulation and air tightness requirements," she said.
The company works with architects and consultants to develop window designs that fit the individual requirements of a house, in some cases supplying different windows for each side of a home.
"One of the most important things to take into account is how the sun hits a home," Jenkins said. "A designer will specify different packages for north and south facing windows."
The performance-based aspect of the Passive House standard makes it attractive for homeowners looking for ways to save energy costs, and high-performance windows can play a role in that.
"It's about reducing energy consumption instead of simply being green for green's sake," Jenkins said.
Serious Materials recently conducted a study that compared the financial return of three major home investments: solar power, insulation upgrades and R5 windows. The high-performance window upgrade returned the investment in the least amount of time via lower energy costs.
For more information, see our Certification/LEED Research Center.
For more information, see our Windows & Doors Research Center.
(Photo courtesy of Serious Materials.)
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Gary Wollenhaupt is an experienced writer and editor, with a background as a daily newspaper reporter as well as corporate and agency public relations and marketing. He is constantly looking for affordable green upgrades to make to his home in eastern Kentucky.www