In the last two weeks, two national groups that certify construction for Passive House Standards conducted their annual conferences. PHIUS was held in Portland, OR; and PHI was held in Maine. Locally, I have completed the first of 3 planned Blower Door tests for a passive concept home under construction; discussed the planned construction with another builder to start later this year; and discussed passive building concepts with another builder planning his first homes next year.
The Passive House concept started in Germany, with construction starting in 1990 on several homes. In German, it is Passiv Haus, PHI for Passiv Haus Institute. The standards followed by this concept require an attention to detail in design and construction of the thermal enclosure. Historically referred to as the envelope, the thermal enclosure involves the exterior bottom, sides and top of the structure.
- Higher than commonly used levels of insulating material,
- windows meeting specific standards and very
- Effective work on air sealing
- Attention to the Solar Orientation of the home to maximize the use of solar heat in the winter
This results in an extremely low energy bill. How low? In the Wichita area, this would translate to an $88 – $110 annual natural gas bill, instead of $500 – $900 bills that I routinely see on Home Energy Audits.
The passive term comes from the idea of using insulation and construction techniques to create a significant energy savings instead of relying on fancy machinery to create that savings. Dr. Wolfgang Feist of Dahrmstat, Germany founded the Passiv Haus Institut in 1996.
Most countries have a local organization that trains and certifies homes and commercial buildings to the Passive Standard. Yes, passive concepts apply to buildings other than homes. These groups train people to apply and measure the standards. They also review the reports on specific buildings and accept or deny actual certification for a specific building.
In the US, this organization has been known as PHIUS. Passive House Institute, US. Ms Klingenberg has been the leading light of this group, which was founded in 2007. There are some things in each country that differ from the original German model of Passiv Haus.
The experience of the professionals working with PHIUS in the US has resulted in some changes to how the concept is applied in the US. For example, the metric units used in the German (and most others in the world) have been translated to the Imperial units used in the US. The collaborative nature of US business groups has been essential to moving the passive concept from being used by a relative few to becoming a market force in the US.
Because these adaptations by PHIUS to the US market, were not acceptable to the original PHI, a divide between the approaches has occurred in the US. It is mostly technical, and both groups agree the concept is still primary. Effective building resulting in low energy use.
Some claims have been made that these concepts are two expensive for the US market. The original Passive House in Illinois was built at a 2003 cost of $94/ sf. That is very favorable with current US construction costs. Since additional people are using the concept and the resulting products that manufacturers are producing, the mass production will bring some drop in costs.
If you wish to read more about the two national conferences for both the PHI and the PHIUS organizations that just finished, you may use these articles.
I will keep you updated on activity in this area about Passive House building activity, as it progresses. Three projects is a great start. I’m glad that builders are willing to try new concepts and that home buyers are willing to step up and buy these homes.
In the introduction of this post, I mentioned a house under construction with the Passive House concept. I conducted the first of 3 Blower Door Tests last week. This test was after the framing and exterior sheathing was completed. Insulation, plumbing, electrical and trades had not started. The second test will be in a few weeks after these trades have done their initial work and put holes in the enclosure. Electric wires, plumbing, HVAC and other necessary conveniences of our lives will be installed in passive concept homes. The third test will be done at the end of construction.
The PHI/PHIUS standard for Air Infiltration as measured by the Blower Door Test is 0.60 – The current 2012 recommended code requirement for this is 3.0 — Wichita/Sedgwick County does not have an energy code in place, but the Kansas City area does. They enforce a 5.0 standard. Typical homes built from 1980 and prior are in a range of 10 – 38 from my testing.
The goal of the builder on this passive concept home was to reach 1.5 on this first test. Then using the Infrared Camera to find areas to caulk, and fixing the penetrations mentioned above, have the next test come in lower.
This test, actually came in at 0.62 — almost the standard. Much better than the expected 1.5 . While the blower door was running, the Infrared found some places that could be fixed. Dan, the carpenter, was right there with a caulking gun. We also found some leakage with biometrics. A back of your hand that is wet, will show you extremely small amounts of air movement. Most builders like to use expanding foam to seal the actual window to the rough opening. We found some of these foamed openings were still leaking. Again the caulking gun was a good answer.