“There’s no doubt that the Passive House approach works. Experience shows that buildings constructed to the standard do use dramatically less energy than conventional structures. They offer excellent air quality, resist excessive solar heating, and maintain comfortable levels of temperature and humidity with little effort on the part of their occupants. ”
Planning, certification, and training. During the planning phase, Passive House builders rely heavily on energy modeling software called the Passive House Planning Package (PHPP). It’s a detailed spreadsheet that accepts user-supplied input values for insulation, glazing, framing characteristics, hvac equipment, and other characteristics, merges them with data on local temperatures and solar radiation, and provides an assessment of the expected energy performance of the completed building.
“The planning package is really complex,” says Belfast, Maine, builder Alan Gibson, whose design-build company recently completed the first certified Passive House in the state. “I’ve seen some architects look at it and just throw up their hands, and I have my own energy-loss and solar-gain spreadsheet that’s much simpler to use. But the PHPP is super detailed – it goes to the level of calculating the heat loss between your hot-water tank and individual faucets.”
The PHPP is available from PHIUS for $225. A simplified trial version can be downloaded for free from the PHIUS website at passivehouse.us/passivehouse/designtools.html.
In addition to supplying software and acting as a general clearinghouse for information, PHIUS certifies (for a variable fee) the energy performance of buildings that have been tested and found to meet its standard. The organization also conducts nine-day training sessions -in Urbana and other places across the U.S. and Canada – in the use of its software and energy-efficient construction methods. Accreditation as a certified Passive House consultant is available to participants who complete the training program – which costs about $2,000 – and pass an exam. According to PHIUS founder and director Katrin Klingenberg, more than 350 people have so far completed the training, among them architects, designers, builders, and more than a few homeowners.
Technically, it’s not necessary to take the training program to build a certified Passive House. Anyone can buy the planning software, use it to build a structure that meets the standard, and have its performance verified by PHIUS. In practice, though, that’s seldom done, and it’s not encouraged by the organization. “We try not to do that anymore,” says Klingenberg. “It’s been done successfully, but it tends to require a lot of hand-holding from us.”
Finding a niche. There’s no doubt that the Passive House approach works. Experience shows that buildings constructed to the standard do use dramatically less energy than conventional structures. They offer excellent air quality, resist excessive solar heating, and maintain comfortable levels of temperature and humidity with little effort on the part of their occupants.
For builders struggling to keep their businesses afloat in difficult times, all of that is secondary to a more fundamental question: Is climbing aboard the Passive House bandwagon a sound business decision? With only a tiny handful of Passive Houses in the U.S. so far (fewer than 20, by most counts), it’s much too soon to draw any firm conclusions. But according to several seasoned builders who have recently completed Passive House projects of their own, the answer is a cautious “yes.”
Salem, Ore., custom home builder Blake Bilyeu enrolled in a Passive House consultant training course offered in Portland in the summer of 2009. “A client had already asked us to design and build a Passive House,” he says. “I actually did the design work for the house as part of the nine-day training session.” The bulk of the training program, Bilyeu notes, was devoted to the nuts and bolts of working with the PHPP software, with much less coverage of hands-on building methods.
Fortunately, Blake and his father, Larry, had already been building high-performance homes for a number of years, including a LEED Platinum home and another built to the Oregon High Performance Home standard. As a result, Blake found the actual construction to be fairly straightforward. “We’ve built plenty that are a lot better than code or Energy Star, and this one just took us a little further,” he says. The Bilyeus’ framing sub was already familiar with the system chosen for the Passive House – double-stud walls on a modified crawlspace foundation, with a raised-heel truss roof. “A big part of making it work out was looking for methods that were most cost-effective and not foreign to our subs,” he says.
Construction of the three-bedroom home began in late August 2009 and was completed in May of the following year. According to Bilyeu, the $300,000 home was one of the company’s more profitable recent projects, which are typically priced between $140 and $175 per square foot (at $159 per foot, the Passive House fell squarely in the middle of that range). “We didn’t give it away for the experience of building one,” he says. “Passive House isn’t going to help anyone if it’s not affordable or profitable for the builder. There are so many standard homes on the market that you can’t build a new one for the same price even without a profit margin. Right now, you really need a niche.”
Posted on February 17, 2011