A Dillingham, Alaska, couple has claimed a world record for airtightness in a 600-sq. ft. home with 28-in. thick walls and a ceiling rated at R-140.
According to the World Record Academy, a blower-door test measured 0.05 air changes per hour at 50 pascals of pressure (ACH50), less than 10% of the very rigorous Passivhaus air-tightness standard of 0.60 ACH50.
The owners are Dr. Tom Marsik, an assistant professor of sustainable energy at the University of Alaska at Fairbanks’ Bristol Bay Campus, and his wife Kristin Donaldson.
The blower-door test was performed on March 6. Witnesses included Dillingham Mayor Alice Ruby and an analyst with the Building Performance Institute who called the results “phenomenally low.”
Efficiency on a very small scale
The two-bedroom, one-bath house is insulated mostly with cellulose and is designed to be comfortable without a conventional heat source. Most of the heat comes from lighting, appliances, body heat and solar gain. The house needs the equivalent of 35 gal. of heating oil a year.
“If society acknowledges the importance of reducing energy consumption, a logical question to ask is: What good does it do to increase the energy efficiency of homes if it is outweighed by escalations in their size?” Marsik wrote in a description of the project in Alaska Building Science News. “The main purpose of this project is to demonstrate that by combining super-efficient construction technology with small house size, an extremely low energy home can be achieved.”
Marsik said the house was built with a “double-frame technique” that included a continuous vapor barrier and both cellulose and fiberglass insulation. “The basic idea is simple,” he wrote. “Build a small box inside a bigger box, seal the small box in a plastic bag, fill the whole cavity between the boxes with insulation, and you will end up with a supertight and superinsulated structure.
Other building features included:
- A heat recovery ventilator
- Triple-pane, argon-filled windows with fiberglass frames.
- Energy Star appliances and compact fluorescent lighting.
- Low-flow plumbing fixtures.
- All-electric operating, with no oil, propane or wood fuel.
Marsik says the extra insulation in the house cost $20,000, but he and his wife will see more than $4,000 in annual savings based on current energy costs. Total construction costs were $169,500.