Kaufman 45′ dome home linked to 34′ garage dome in Forest Ranch California
Utilizes Heat Recovery Ventilator & Geothermal Energy for Heating & Cooling
The following article was taken from the Summer 2009 Butte Environmental Council’s (BEC) News. The geodesic dome home featured was built from American Ingenuity dome building kits. BEC is a not-for-profit public benefit corporation. Founded in 1975, BEC protects the land, air, and water of Butte County California through advocacy, environmental education, and information and referral services.
ChicoEco Highlights a Geodesic
By Nani Teves
Hidden among the trees in the mountain community of Forest Ranch is the most amazing example of living more responsibly by combining conservation and cutting edge. Ron Kaufman and Marti Leicester spent four years planning and 14 months building their geothermally heated and cooled, concrete geodesic dome home, which, when all was said and done was approximately the same cost as building a traditional house of the same size.
A geodesic dome looks like the top half of a soccer ball, and theirs is two domes connected by a 12 ft length. They used concrete as a building material because it is low maintenance, highly insulated, insect resistant, and most importantly for their area – fire resistant. They built to optimize passive solar potential usinged double pane windows.
Throughout the house, renewable and reused building materials were used including the floor, which is made from Marmoleum, a durable linoleum made from linseed oil, jute and rosin. For carpeted areas, 1ft by 2ft squares were used, making it possible to replace only damage areas. Framing studs were reused to build the loft, the kitchen cabinets are bamboo and the stairs, window seats and baseboards are all make from a material called Evergrain, which consists of 50% HDPE (typically recycled milk bottles) and 50% wood fibers (typically old pallets).
One of the most fascinating things about this house is that it uses geothermal energy for heating and cooling. The system was expensive but they wanted to push the technology forward by experimenting. How the system works is heat is collected from the dome interior and then pumped into the ground during cooling, and reversed during heating. They hired an out of state company (no one was available locally or even in California) to drill four 180ft deep holes. Crystal Air in Weaverville installed the system by placing tubing surrounded by Bentonite in the holes. A two-way pump is run using energy from PG&E and a back-up generator, and the extra heat from this system is used to preheat the water for their on-demand tankless water heater.
Another unique feature they included in the design is a Heat Recovery Ventilator (HRV) System. The HRV brings in fresh air and exhausts stale air, while transferring a significant portion of the heat in the stale air to the incoming fresh air. It also maintains a slightly positive air pressure in the dome so that pollen and dust are not drawn in through open doors and windows.
From the jars reused to hold screws, to the dome itself, this house is an example of how fun it can be to research, experiment and live outside the box.
Ai is sometimes asked – Which is more efficient a Heat Recovery Ventilator or Dehumidifiers to control moisture inside the dome?
One of American Ingenuity’s Missouri Dome Owners, Mr. Nicks, sent us the following email. “I was having trouble with winter humidity in my dome until this February 2006 when I purchased and installed a Heat Recovery Ventilator (HRV). Air quality is noticeable fresher and relative humidity is under control. The HRV has eliminated the need to run dehumidifiers during the winter for me. Additionally, small dehumidifiers are electricity hogs (costing more to operate than central air in the summer).
My home does have high cfm fans in all bathrooms and kitchen vent fans as well. I tied my bathroom vents to the HRV which has a humidistat that kicks it into high gear when the bath humidity hits it.
My dome is still a work in progress, but I love being the first and only one around here to “think outside the rectangle” in home design. The spaces in a dome have amazing character….anyway just wanted to share an idea that has helped me defeat the humidity in my dome.”
Ai asked him where and how did he install is Heat Recovery Ventilator?
He replied, “I installed the HRV in my utility room with an insulated intake duct through a joist space. The unit I installed was manufactured by Lifebreath (model 200 max). Depending on which standard is used it may be slightly undersized, but works fine. Three of my bathroom vent fans had previously come together in the utility room to exit through a single 6” vent (I had a box with dampers to prevent backflow). I connected the HRV to those three bath vents which allowed me to pull air from three different floors of my dome.
The HRV I installed has a humidistat in its exhaust air stream (household intake). When someone is taking a shower that humidity causes the HRV humidistat to switch the fan to high speed. I have mine set on low speed continuous as a default.”
Are electric vents necessary at the peak of the dome as well as in the bathrooms to prevent moisture buildup?
A: Yes. The electric exhaust vents are installed in a vertical wall near the top of the dome, in top center of the dome, in bathrooms and above stove/microwave to exhaust water vapor (from laundry, cooking, showering, etc.) In interior walls, use galvanized metal ducting that extends down the interior wall, through the floor joist and vents out under an entryway. And in some areas install a heat recovery ventilator or energy recovery ventilator to remove moisture.