The Passive House: Sealed for Freshness

[M II A II R II K]

The Passive House: Sealed for Freshness


August 14, 2013

By SANDY KEENAN

Read More: http://www.nytimes.com/2013/08/15/ga...w-nytimes&_r=0

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On paper, at least, the Ritchies’ home sounds too good to be true: an environmentally responsible house without traditional heating and air-conditioning systems that will be an airy 70 to 74 degrees on the coldest day of winter and the hottest day of summer, but use only a fraction of the energy consumed by a typical house. And yet it’s not some experiment or futuristic dream.

- Nearly 30,000 of these houses have already been built in Europe. In Germany, an entire neighborhood with 5,000 of these super-insulated, low-energy homes is under construction, and the City of Brussels is rewriting its building code to reflect passive standards. But in the United States, since the first passive house went up 10 years ago, in Urbana, Ill., only about 90 have been certified.

- Why aren’t they catching on here? Part of the problem is the cost. Higher fuel prices and energy taxes in Europe provide a major incentive to embrace passive standards, which are complicated and make construction more expensive. In this country, it could be a decade or more before the energy savings someone like Don Freas enjoys in his 1,150-square-foot passive house in Olympia, Wash., offsets the extra $30,000 or so it cost to build. “But those are such non-sexy ideas,” said Mr. Freas, 61, who is a sculptor and poet. “What matters is that I have never lived in such a comfortable house.”

- Proponents of passive building argue that the additional cost (which is estimated at 5 to 20 percent) will come down once construction reaches critical mass and more American manufacturers are on board. And there are a few signs that day may be coming. More than 1,000 architects, builders and consultants have received passive-house training in this country; at least 60 houses or multifamily projects are in the works; and Marvin Windows, a mainstream manufacturer based in Minnesota, recently began making windows that meet passive certification standards. For all that, there are plenty of people who aren’t buying it — even some of those who support passive principles.

- The very idea of a passive house is counterintuitive. And when just explaining what it is remains so difficult, proselytizing is that much harder. As Mr. Freas said, “It’s like trying to describe an environment that we, as Americans, have no experience with.” The basic idea is that these houses are so airtight that warm air won’t leak out in the winter, and cool air won’t leak out in the summer. Windows are three panes thick, and there is far more insulation than you would find in a standard American home.

- Stale indoor air is exchanged for fresh outdoor air without altering the internal temperature by mechanical systems you would not find in a conventional house: things like heat-recovery ventilators, which draw the heat from outgoing air and mix it with incoming air from outside in the winter, and do the opposite in the summer. Vents that look like small, round audio speakers are placed throughout the house to exchange fresh air. These devices have prevented the formation of mold, which plagued the passive-solar movement of the 1970s and 1980s.

- During construction, special fog machines and infrared cameras are often brought in to detect the smallest air leaks. Special tapes, gaskets and sealants are used on the wall seams to ensure they won’t break down over time and result in drafts. And the more extreme the weather, the more insulation is needed. In a place as cold as Minnesota, a passive home’s walls would have to be 18 inches thick, but even in the more temperate Portland, Ore., 12 to 14 inches is typical. This kind of meticulous construction results in big energy savings, but just how much is a matter of some dispute.

- Figuring out how to make the model work in the hot, humid Southeast is a bigger challenge, something the Europeans have not had to deal with. With this in mind, Ms. Klingenberg’s organization is working to develop American standards, taking into account variations in energy use and leakage rates from one climate zone to another; they are expected to be released this fall.

- Early passive houses were boxy, with few windows and even less style, but as designers have grown more comfortable with the modeling software, homes have become more elegant and inventive. In the Ritchies’ house, everything feels textured and substantial, like the metal-framed windows from Lithuania, the skylights from Poland, and the touches of spruce throughout, which came from a tree on the long, thin lot that had to come down.

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