StoryImage( ‘/Images/Story//Auto-img-117571449118038.jpg’, ‘Photo by Soina Vogl’, ‘South overhang of Zaderej One Watt HouseTM near Oregon, Ill.‘);
Its the house with the blue roof. Color may be the easy way to locate Victor and Polly Zaderejs house, but its not the only unusual feature of the new home nearing completion southeast of Oregon, Ill.
Built on principles adapted from the German Passivhaus, the home is extremely energy efficient, using about 1/10 the energy for heating as a conventional house, but costing only about 1/10 more to build. It is referred to by Marko Spiegel as the One-Watt HouseTM, based on its consuming only 1 watt of heating energy per square foot as opposed to the 10 watts used in conventional buildings.
We first became aware of the Passivhaus movement at the 2006 Renewable Energy and Sustainable Lifestyle fair when Dr. Bernd Steinmuller made his keynote presentation about energy efficiency in buildings. He stressed heavy insulation to save money on heating bills and cut CO2 releases. Although Germany is a world leader in efficient housing with most of the worlds 10,000 passive houses in Europe, Steinmuller feels that German buildings could be still more efficient as could those in the U.S.
Zaderej and his friend and colleague, Spiegel, have known of extreme energy efficiency for several years, traveling to Germany frequently to be updated on new developments. After studying the principles and examining houses, the two engineers decided to put their knowledge to work in an actual home. They located materials as similar to those used in Germany as they could find in North America. Their searches were widethe doors and windows were made in Saskatchewan.
The exterior of the home is heavily insulated with R 40 insulation in the walls and R 50 in the ceilings. Insulation is not an afterthoughtit is an integral part of the walls and roof, constructed of SIPs (structurally integrated panels) formed by 10 inches of foam insulation (for walls) sandwiched between 2 inch-thick panels of chip board. Posts and beams add strength to the exterior. ICFs (insulated concrete forms) provide an R rating of 20 under the foundation.
On winter days, large south-facing double-glazed hard coat low E windows with a U rating of 33 collect the suns heat, which is stored in the concrete floor of the lower level for release during the night. North, west and east windows are triple glazed with a U rating of 24.
One of the two 120-gallon superinsulated all-plastic Marathon water heaters provides for domestic use. Between 80 and 90 percent of shower water heat is returned to the water heater. The second sends hot water to the air furnace, which then circulates the heat. The water heaters are on demand metering with timers set to turn on at night.
An air-to-air heat exchanger with a whole house ventilator removes stale air from the kitchen, bathrooms and laundry. It also recovers more than 50 percent of the heat from outgoing air. A space beneath the steel roof collects warm air, which is blown into the stone wall in the office. South roof overhangs protect the interior from the summer suns heat.
An earth tube brings air with the grounds steady temperature into what the engineers refer to as an earth room, where it is stored for circulation throughout the house. In winter, the earth is warmer than the outdoor air; in summer, it is cooler, providing relief from temperature swings.
This winter, Zaderej and Spiegel invited us to a readingof a thermometer. It read 68 degrees at 9 p.m. on a below-zero night. The furnace has not run since late February. Ten 200 watt light bulbs left on overnight maintain a comfortable level even when the outdoor temperature is below freezing.
Contractor Rick McCanse explains that thermal mass provides thermal lag. Although he built the house, McCanse admits, Its pretty amazing.
The Zaderejs are now planning their landscaping with an emphasis on the large lawn. They recently asked us to advise them on native dry prairie grasses and forbs, which need almost no care, look beautiful, and remain a respectable short height. Their passion for passive will extend to the yard so theres no mowing!
Drs. Robert and Sonia Vogl are founders and officers of the Illinois Renewable Energy Association and coordinate the annual Renewable Energy and Sustainable Lifestyle Fair. They have 3.2 kW of PV and a 1 kW wind generator at their home. Forty acres of their 180-acre home farm are in ecological restorations. They are also active in preserving natural areas. They are retired professors from Northern Illinois University.
from the April 4-10, 2007, issue