
I’ll admit it, the word “green” sometimes feels passe. It’s been used and over-abused to a point where it’s almost unreliable. The Passive House standard that’s becoming more prevalent in Portland, however, doesn’t mention green anywhere. It’s strictly about cutting energy consumption to next to nothing, making a home Net Zero, and saving enough on your energy bills to afford an electric bike, or even an electric car! It is reliable, it’s about getting our priorities straight – and I’m fascinated.
First, however, let’s be clear that Passive House Standard and Passive Solar design, while they work well together, have two different definitions. Passive Solar design places the majority of its windows on south facing walls to maximize heat gain. It also incorporates elements such as tile flooring to absorb and slowly distribute that heat, or seasonal foliage to protect from too much sun.
PassiveHaus incorporates passive solar design, but is also calls for an unbelievably air tight and super insulated envelope. To achieve this usually requires several important changes above and beyond standard building codes. Some of the main components that make up a PassiveHaus include thicker walls and doors for added insulation, higher quality (lower U-value) windows to prevent heat loss, and advanced framing techniques that reduce thermal bridging. Add to this an efficient heat pump and HRV (heat recovery ventilator) and you have yourself a “passive”, contained machines that breathes controlled volumes of air with near perfect efficiency.
Here are a few excerpts defining the Passive House standard from the Passive House Institute US:
“The Passive House concept represents today’s highest energy standard with the promise of slashing the heating energy consumption of buildings by an amazing 90%. Widespread application of the Passive House design would have a dramatic impact on energy conservation. These homes are primarily heated by passive solar gain and by internal gains from people, electrical equipment, etc. Energy losses are minimized. Any remaining heat demand is provided by an extremely small source. Avoidance of heat gain through shading and window orientation also helps to limit any cooling load, which is similarly minimized. An energy recovery ventilator provides a constant, balanced fresh air supply. The result is an impressive system that not only saves up to 90% of space heating costs, but also provides a uniquely terrific indoor air quality.”
So far, Portland only has a hand-full of PassivHaus homes, and all of them are privately owned or being custom built. To experience some of these super homes in person, I recommend the upcoming 2010 Build it Green home tour.
For more local articles and resources, check out these links:
www.buildinggreen.com
http://djcoregon.com/news/2010/05/14/passive-house-popular-in-portland/
http://www.phnw.org/Passive_House_Northwest.html
Posted August 12th, 2010 in Blog, Featured | Comments Off