Corps of Engineers builds 'passive' townhouses in Germany to slash energy use
November 10, 2009
- Army family housing pilot project meets stringent criteria for energy savings, using insulation and passive solar heating.
- The PassivhAfA$us units should use only 25% of the energy consumed even by highly efficient houses built to German EnEV standards.
- The passive houses are anticipated to consume only one quarter of the energy demanded by an EnEV home.
ANSBACH, Germany - This small garrison in northern Bavaria will soon be home to the most energy efficient homes the U.S. Army has ever built.
Foot-thick insulation, triple-paned fiberglass windows, and foam-sealed utilities are just some of the features these super energy-efficient homes - called PassivhAfA$user, or "Passive Houses" in English - will have.
"These houses are like energy efficiency on steroids," said James McPeak, U.S. Army Corps of Engineers Europe District project engineer at Ansbach. "Every energy-saving commodity is included in these houses."
The Corps will oversee the construction of 22 passive houses by late 2010 as part of a $52 million family housing program that will ultimately place 106 new homes at the installation. Although the remaining 84 homes won't meet PassivhAfA$us standards, they will adhere to German EnEV energy-saving standards, which are still more energy efficient than American standards.
"This is a pilot project for U.S. Army in Europe using a combination of U.S. Army housing requirements with cutting-edge German design criteria," said McPeak. "PassivhAfA$us units are 15 to 20 percent more expensive to build than a standard German house, but large long-term energy savings are expected."
The passive houses are anticipated to consume only 25 percent of the energy demanded by an EnEV home, McPeak said. The most impressive feature, he added, is the innovative heating and ventilation design system, which captures and recycles about 92 percent of "waste heat" from the lighting fixtures, major appliances, ground heat pump circuits, exhaust air and even people or animals in the rooms to allow the house to heat itself.
This passive, whole-building approach requires an air-tight seal around every utility cable, window and door. The tightness of the house keeps a consistent temperature in summer or winter, with only a one- or two-degree temperature difference between the center of the room and the area by the window.
The passive house standards are more rigorous than others, such as Leadership in Energy and Environment Design or Sustainable Project Rating Tool.
"Comparing passive house standards to, say, LEED is like comparing apples and oranges," said McPeak. "LEED takes into account things like proximity to schools, shopping and highways when getting a rating. Passive house design is just about energy efficiency, so a true comparison can't be made."
Despite all the advanced technology put into the construction of these houses, it is designed to be simple for the occupants to live in and use.
"The family living inside will not see any difference. There is no space-age control panel that requires a master's degree in electronics to operate," said Darren Walls, a district project manager. "There will be regular thermostats on the wall, and everything else is in a mechanical room not located in the house."
When Soldiers and their families drive into the picturesque community with tree-lined streets and fenced back yards, the only visible difference will be roof-mounted solar panels, part of the primary passive-solar heating system. But from the ground up, these homes are like nothing Norman Rockwell ever saw or imagined.
"These energy-efficient homes are a tremendous contribution to our environment because they preserve our limited, vital resources," said Command Sgt. Maj. Lester Stephens from the U.S. Army Garrison Ansbach.
"In the long run, these homes are also an important improvement to our quality of life within our community," Stephens said. "Instead of spending money on utility bills, we can invest the money saved on improving the morale for our Soldiers and their families."
There are approximately 200,000 PassivhAfA$us units in Europe, primarily in Germany, Austria and Scandinavia, and the popularity is rapidly spreading. According to McPeak, the passive house could become the standard new house design in Europe within 10 years.