It all started on Twitter. @AIAWichita @moongodess316 and I had some fun over building an Igloo.
I saw this Tweet and immediately thought of a quote from Dr. Joseph Lstiburek: “The Igloo was the First Passive House.” Joe is an engineer by training and has been working with buildings, insulation and energy use for over 30 years. His Building Science Corporation, based in Massachusetts, conducts research and is one of the best sources of verified information on building energy efficiency in buildings.
So I tweeted back.
What is the difference between a Passive House and a regular house? What is the buzz all about?
When you build a home you can use lots of insulation to reduce the amount of electricity and gas to heat and cool the home.
You can use a lot of high tech equipment to reduce the amount of electricity and gas to heat and cool the home. You can also do both.
The Passive House was developed in Germany, so you see it referred to at times as Passiv Haus.
We know that insulation works and that more insulation works better. As the cost of electric and gas goes up, it makes financial sense to add insulation to a home or business. In 2000, the local cost of Electricity was 8 – 9 cents, the recommended level of attic insulation was R-30. Today the cost of electricity is 12 – 13 cents and the recommended level of insulation is R-49. Both have increased about 1/3 in 1 years. We also know that air movement, cold drafts, makes people uncomfortable and causes insulation to not work as effectively.
The sources of air entering a home are usually related to corners. Since we like living in buildings that have square corners there are a lot of them in a home. Windows do not usually cause air leakage. How they are installed can cause air leakage. The age or the quality of the window does not seem to matter when installation mistakes occur.
The primary requirements for a passive ouse certification are based on Energy Usage and creating a structure that needs very little energy for heating and cooling. These standards are effectively summarized with these two limits.
- Total primary energy (source energy for electricity, etc.) consumption (primary energy for heating, hot water and electricity) must not be more than 120 kWh/m² per year (37900 btu/ft² per year)
- The building must not leak more air than 0.6 times the house volume per hour (n50 ≤ 0.6 / hour) at 50 Pa (N/m²) as tested by a blower door.
In our Twitter Conversation, Angee McBustee tweeted a question about how is building a igloo in Wichita. Then I responded with the offer to run the blower door test. As you can see from the primary requirements the Blower Door result is very important to a passive house.
How good is a Blower Door Test of 0.6, as required by Passive House? Energy Star New Homes require a Blower Door Test of 5.0 or less. New homes in Wichita routinely test around 4.0. In the blower door testing, lower is better.
For standard construction, I have tested several homes at 1.0. There is one home that I have tested with a lower result. A custom home in Butler County is under construction. They had me do a Blower Door test after it was sheathed. No insulation, no drywall. The test result was 0.62. We were able to find several leaks using biometrics and the infrared camera. That was last September. I returned in December to test it a 2nd time, the results were so low, that I didn’t have the right test equipment to measure the result. I would estimate it to be in the 0.30 range. I now have the equipment to test a home like that.
In February, I have been accepted for training and certification as a Passive House Rater/Verifier. Christine is building the home in Butler County, I want to thank her for the push to obtain this certification.
In the Twitter Conversation, AIA Wichita came back and said they were posting an information tweet.
Thanks to Angee and AIA Wichita for a nice idea for a Blog Post.