Window to the Future
A house in Bethesda and guesthouse in Garrett Park are pushing the boundaries of green: They rely on insulation for heating and cooling.
Architect David Peabody has dubbed it “The New American Foursquare,”a five-bedroom, 41/2-bath showplace with four floors of living space, including a walkout basement and all the design flourishes that have made foursquares popular in the region for more than a century.
One thing, however, will be notably missing: a furnace. This home won’t have a conventional heating system—and it won’t have solar panels or windmills, either. The heating bill will be lower: about one-tenth what it takes to warm a conventional house of the same 4,400-square-footage. And when construction wraps up early next spring, the builders plan to certify the house at 4717 North Chelsea Lane in Bethesda as Greater Washington’s first “Passive House.”
“We thought the marriage of those two components—Passive House with traditional American architecture—would be a winner,” says Brendan O’Neill Sr. of O’Neill Development, the Gaithersburg homebuilder that partnered with Alexandria-based Peabody Architects on the venture, which went on the market in August.
The partners were planning to offer it for $1.5 million to $1.6 million, a lower price tag than two other environmentally friendly homes recently built in the area: The Incredibly Green Home of Chevy Chase and the Bethesda Zero house, both of which sold within the last year for about $1.8 million.
Those homes were built with solar panels and other so-called “green bling,” but Peabody’s design takes a different approach to the low emissions goal: Instead of generating renewable power, it simply will use little electricity. This super-insulated house will be so tightly and carefully constructed, the builders say, that heating it will require little more than the warmth of the bodies inside.
That’s not to say it’ll be contraption free: An energy recovery ventilator (ERV) will cull the heat from the outgoing stale air and transfer it to the fresh air continuously circulating into the house. (A coil of tubing called a ground loop under the slab foundation will heat incoming air in winter and cool it in summer before it enters the ERV. During colder months, heat also will be generated by coils linked to the hot water heater, an operation that requires about as much electricity as a hair dryer, Peabody says.)
Peabody estimates the house will cost little more than $700 a year to heat and cool to roughly 68 degrees, compared with nearly $7,000 for a conventional house of the same size in the same ZIP code. Though the builders are not adding solar panels, the house will be “solar ready.” The new owners could add a few solar panels and achieve net zero status on a home that looks just like other area foursquares, those boxily elegant homes first sold as late 19th-century mail-order kits from the Sears, Roebuck and Co. catalog.
Although new in the United States, Passive House construction has been around for nearly two decades. It was pioneered by Dr. Wolfgang Feist, who founded the Passivhaus Institut in Darmstadt, Germany, in 1996. He was inspired by super-insulated homes built in this country in the 1970s. Those houses were so airtight that they ran into problems with indoor air quality, condensation and mold. But the addition of ERVs and other “heat exchanging” technologies and design improvements have solved those problems. In a Passive House, the ERV replaces one-third of the stale air with fresh air every hour.
The Passivhaus, as it’s known abroad, now encompasses more than 15,000 homes, offices, schools and hospitals in northern Europe. And the Passive House energy standard is rapidly entering European building codes in the same way many U.S. cities and counties—including Montgomery—have adopted green building standards such as Leadership in Energy & Environmental Design (LEED).
“We just see these houses as the future,” Peabody says. He thinks the energy savings and simplicity of design will attract homebuyers put off by more complex, pricey and high-maintenance solar, geothermal and other green systems.
The first Passive House in this country was completed in 2003 in Urbana, Ill., and only 13 have been certified in the United States since 2008, according to the Passive House Institute U.S., which received a license that year from the Passivhaus Institut.
“It’s just beginning to pick up speed,” says Brian Uher, co-owner and managing director of Amicus Consulting Services, a Kensington company that provides clients with advice on the best building practices, including emerging green technologies. “It’s a much more aggressive standard than anything else we have in the country.”
In the Bethesda area, a couple of cutting-edge “green” building projects this past year incorporated elements of Passive House construction. Elizabeth Glidden-Boyle consulted with Amicus about replacing her old garage in Garrett Park with a well-insulated, loft-style guesthouse that Uher says will require about half the energy of a conventional house its size—without renewable power accessories such as solar panels or geothermal heating systems.
“I had no faith at all that this could work,” says Michael Johnson, owner of A.R.T. Design Build, the Bethesda company hired to do the construction. But now that it’s up, he says he expects to be doing more super-insulated building and remodeling.
Johnson’s company wrapped the structure in four different layers, from rigid foam to Tyvek, and added an ERV. It also installed a backup system: a “suitcase” unit that can be used to heat or cool the house, although the goal is to use it as little as possible. Because Glidden-Boyle plans to use the new building only part of the year as a guesthouse, it didn’t make sense to spend more on designing and insulating the house to achieve Passive House certification.
“We would have had to increase the costs fairly substantially, given its size, and decided against it,” Uher says. Even so, the structure will cost 50 percent to 60 percent less to heat and cool than a conventional house of the same size.
Glidden-Boyle hadn’t tested it out on guests yet, but the insulation and triple-glazed windows already have created a quiet space. “I love walking into it and feeling the silence and the light,” she says.
Peabody’s Bethesda Foursquare will be the first true Passive House in the area. But until it’s finished, nobody knows for certain if this energy efficiency standard is achievable in this area.
So far, Passive Houses have gone up mostly in the Midwest and New England, regions that, like Germany, don’t have the kind of hot, muggy summers that send air-conditioning bills through the roof.
“Nobody wants to be the first,” Peabody says. “They want to be the second, but they don’t want to be the guinea pig.”
Mark Scott, owner of Mark IV Builders in Bethesda, has heard good things about the Passive House system in the last year or two, but is happy to let Peabody and O’Neill go first.
“I’d rather watch them be on the bleeding edge, and then I’ll take over on the leading edge,” Scott says. He expects the Passive House and other so-called green building systems won’t enter the mainstream for another decade or so. But “the Passive House has a better chance than an active solar house…,” he says. “There’s an awful lot of ‘eco bling’ out there that I don’t subscribe to.”
Peabody says he once was skeptical that the German approach could sell in this country, particularly in the conservative Washington area. But as a certified Passive House consultant, he now tries to dispel what he considers misconceptions.
“I don’t think Passive House is extreme, and one of the goals of this house is to prove that,” Peabody says. “It can be very traditional, and it’s actually very economical if you are looking at the true cost of a house over time.”