Preview: expect some changes in the Passive House certification
Passive House proponents will gather for the 8th annual North American Conference to discuss the Passive House certification and some upcoming alterations that may make it more popular in North America.
Passive House was developed in Germany (where it's known as Passivehaus) by physicist Wolfgang Feist in the early 1990s. Since then more than 20,000 homes have been certified in Europe and a few dozen have been or are under construction in the U.S.
The goal of passive house is to achieve significant energy savings for heating and cooing through design and construction techniques without using active technology such as solar photovoltaics or solar thermal water heating systems.
ProudGreenHome.com spoke with Michael Knezovich, director of communications at Passive House Institute US, prior to the conference which runs Oct. 15-19, 2013, in Pittsburgh, Pa.
Q: What can people expect at the conference?
A: Our keynote speaker is HUD Secretary Shaun Donovan, and other speakers include Sean Penrith, executive director of the Climate Trust, and Sebastian Moreno-Vacca, an architect and educator from Belgium.
Last year we had over 400 people and 30 exhibitors and we expect more than that this year.
Q: What's in the future for Passive House in the U.S.?
A: It's growing out of sort of a boutique concept into something that people understand and could go mainstream. We're doing a lot to make that happen, we've tried to "Americanize" it and connect with other rating programs.
Previously, you earned a Passive House designation and it didn't connect up with other market standards and certifications. We created a program called Passive House Plus that incorporates RESnet quality assurance protocols into our passive certification process. A homeowner can get passive review and confirmation and they also get a HERS rating which is probably the most widely used index.
We've worked with the Department of Energy to make the Passive House process also earn DOE Challenge Home status.
For designers, builders and owners this big plus. Since we did that we've see the demand for certification grow really quickly because it's more valuable.
Q: Where can Passive House grow its influence?
A: The name "Passive House" is somewhat unfortunate in that it suggests it's only for single-family residential building, but in fact it's somewhat easier to obtain and more cost-effective to obtain in larger implementations. It's perfect for affordable housing for example. One of the stops on the tour in Pittsburgh is a retrofit of an old YMCA building using Passive House principles.
We're seeing more commercial and multifamily projects come in for certification and we think that's really exciting in terms of saving energy retrofitting existing buildings. Rebuilding a building when you've got dozens of people living it really is the biggest bang for the buck.
Q: One of the criticisms of Passive House has been the adherence to a set of standards developed for Germany. Is there movement on adapting the standard to different climate zones?
A: We've seen Passive House implemented in every climate zone except for Florida, but we have seen it in Louisiana, Maine and California. We've found that although the idea of a single numerical standard like the one in Germany is very attractive and has this "Holy Grail" quality, it really isn't cost effective for all climates and it actually provides a kind of disincentive in some areas. We're working on a retrofit standard that will be more inclusive and reflective of the fact you can't control thermal bridging in some types of construction.
We're also combing through all the data from the projects that have been certified to adjust the standard. They may be the same in many areas, but in some areas it may get more strict. In parts of California it's easy to hit the standard but you actually leave some cost-effective savings on the table. In Louisiana, you have the high humidity situation and you have a different set of problems to solve.
The Passive House principles are not that exotic and we don't want people to not bother doing these things no matter where you are because it looks impossible to hit the number.
Passive House Performance Characteristics
- Airtight building shell ≤ 0.6 ACH @ 50 pascal pressure, measured by blower-door test.
- Annual heat requirement ≤ 15 kWh/m2/year
- (4.75 kBtu/sf/yr)
- Primary Energy ≤ 120 kWh/m2/year (38.1 kBtu/sf/yr)
In addition, the following are recommendations, varying with climate:
- Window u-value ≤ 0.8 W/m2/K
- Ventilation system with heat recovery with ≥ 75% efficiency with low electric consumption @ 0.45 Wh/m3
- Thermal Bridge Free Construction ≤ 0.01 W/mK
Source: Passive House US
Read more about Green Home Certifications.
Companies: Department of Energy
Gary Wollenhaupt is an experienced writer and editor, with a background as a daily newspaper reporter as well as corporate and agency public relations and marketing. He is constantly looking for affordable green upgrades to make to his home in eastern Kentucky.www