JLC Passive House Article: Part 3

Excerpt

“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.

(author’s note: Below, Gibson refers to “hiring a Passive House consultant is sort of like bringing in a mechanical engineer to work with the builder and architect to design the heating system“. This is where the rubber meets the road when selecting a builder. This statement creates a good example for hiring a design + build company which has a certified Passive House consultant on the design team. In our case, having a certified PH consultant as our lead designer, we’ve found this to greatly streamline our entire development process which ultimately keeps costs down ).

article continued…

Does certification matter? Alan Gibson is among the few builders who have completed a certified Passive House project without formal training. The three-bedroom SIP structure, built at a cost of $160 per square foot, was constructed as a prototype for a 36-unit co-housing project that’s still in the planning stage, and it now serves as office space for Gibson and his partner.

“Hiring a Passive House consultant is sort of like bringing in a mechanical engineer to work with the builder and architect to design the heating system,” Gibson says. “But we decided not to do it that way. We’ve used a lot of energy-modeling software, so we just got the PHPP and started filling out the spreadsheet. The training would definitely have made it easier, but we were able to do it on our own.”

Gibson’s company, G-O Logic Homes, has other Passive House projects in the works as well. It was recently awarded a contract to build a Passive House–certified residence hall at a local college. “We wanted to be the first Passive House in Maine, and we get a certain amount of mileage from that,” Gibson says.

Still, he doubts that the term “Passive House” is familiar enough to make much of an impression on the public at large. “What really gets people excited is hearing that we can build them a house they can heat with the equivalent of a couple of hair dryers,” he says. “If you said anything about kilowatt hours per square meter, they’d say, ‘huh?’” For the time being, Gibson suggests, builders in some markets might consider using the Passive House building methods and planning software without seeking certification – and without holding energy use to the extremely low level called for by the standard.

“If someone came along and wanted us to build them a certified Passive House we’d be happy to do that,” Gibson says. “But if someone had a lesser energy goal, we’d be happy to do that, too.” It’s possible, he observes, to fall far short of the strict Passive House standard and still have a very efficient house. “I did some numbers once, and as I recall, the difference between meeting the standard for heating and using half again as much as it allowed was a matter of something like $100 worth of heat over the course of a year.”

Paddling into the mainstream. As freshly credentialed Passive House consultants continue to emerge from the PHIUS training program, it will be interesting to see what the next few years bring. Klingenberg believes that the steady increase in the number of certified consultants will jump-start demand for their services. “Consultants have an interest in getting a certified project done,” she says. “To keep their certification, they need to finish a project within two years. We want to focus on training people who will use it.”

The strategy seems to be paying off. According to Klingenberg, more than 100 Passive Houses are under construction or in the process of having their plans pre-certified. “Things are happening fast,” she says. “It took many years to get to this point in Europe. In the U.S., growth is already exponential.”

There are an estimated 25,000 Passive Houses in Europe, most of them in Germany and Scandinavia. While even that is a relatively modest number, it has attracted the attention of building-product manufacturers. Passive House builders in Europe have a wide range of mission-specific products and material at their disposal, such as foams, tapes, sealants, and spectacularly well-insulated (and expensive) wood-framed windows. Hvac equipment designed to handle extremely low heating and cooling loads is also widely available overseas, including so-called “magic box” appliances, which combine an air-source heat pump, a heat-recovery ventilator, and a hot-water tank in one engineered package. Passive House boosters are hoping that a similar “mainstreaming” process could happen here, and that it will lead to thousands of U.S. and Canadian Passive Houses within a very few years. – Jon Vara

Part 1

Part 2

Part 3

Posted on February 17, 2011

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