ET: Why, in your opinion, is there so much more buzz about Passive House right now than actual projects in the pipeline awaiting certification?
SH: Most architects know what Passive House is, and you hear a lot about Passive House standards in the [green building] news, but the reality of it is that there aren’t that many built units. It’s developing, and someday it will be a significant portion of the in-ground building market, but right now it’s just sort of an idea that’s percolating through everyone’s theoretical framework.
image via Beaton Construction
ET: What are some of the factors that have kept this standard, so far, from going more mainstream (such as LEED certification)?
SH: To build to the Passive House standard requires a real commitment to advanced building science and a modification of the procedures of building. Although standard construction techniques are often used in Passive House, they are used in multiple layers or in new ways that require technically precise design and installation. Passive House design also requires a Certified Passive House Consultant, or CPHC, someone trained in the Passive House Planning Package (PHPP) and the performance principles of Passive House. And that training is a lot more difficult to master than what’s required to become LEED accredited. So today there are far fewer CPHCs than LEED APs. To give LEED and the USGBC their proper due, they have done an amazing job at capitalizing on a green-hungry marketplace, and should be commended for their marketing ability and collaboration with industry and government.
But LEED doesn’t really represent a radical shift in how buildings are built. The reality of it is, [building to LEED] is fairly easy to do. [But] when you build a building that has a 90 percent reduction in its heat load, it’s a pretty radical endeavor. These buildings have much more thermally resistant walls – that means they’re often much thicker than a traditional wall assembly. The windows are triple-paned in this [Pacific Northwest] climate, and there’s great care taken in the assembly of the building shell to create an airtight layer. In Passive House building, we specifically at the blueprint level identify where the airtight layer is and include it as a separate line on the building cross-sections. So there’s great deal of specific planning going into how this air barrier is created and how it plays into construction.
There’s a lot more detail required. But it’s like anything else: the first one you do is kind of difficult, but once you get used to doing them that way, and you can’t imagine doing it any other way.
image via Digital Construction
ET: Are the associated costs higher than building to LEED Gold or Platinum?
SH: LEED Gold or Platinum are high performance enough to make them more expensive in that guise, but you also spend more money [simply getting certified] with those certifications. I’d say Passive House is cost-neutral as compared to LEED Gold or Platinum.
The number of Passive House projects are doubling every year. Our goal with the national leadership is to make Passive House cost-neutral to conventional construction. I don’t know if we’re going to get there, but we’re going to get damn close. And we’re certainly going to get close to [the costs associated with building to] Energy Star 3 or 4.
ET: How does the Passive House standard compare to the standard set by the Living Building Challenge (LBC)? Are they compatible/complementary?
SH: I see Passive House as a perfectly complementary and parallel path to Living Buildings. The LBC address all aspects of the built environment in a comprehensive way, beginning with a philosophically-oriented concept of land use and flowing through to the end goal: a building that gives back to the planet and its inhabitants.
ET: It seems that any project going for net zero or grid positive energy use would do well to adopt Passive House construction standards, since building this way minimizes the amount of energy that needs to be supplied via onsite renewable energy systems (which can be quite expensive).
SH: Definitely. It’s so politically incorrect to say “renewables are dumb,” but the truth is, they’re only [not dumb] if you have [already] optimized the building envelope. If you’re spending extra money on renewable power to heat an envelope that’s inefficient, or grossly inefficient, you’re just enabling poor building.
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