Avenson solar home. Photo by Michele Melio.
John Avenson offers free tours of his near zero solar home in Westminster to the public. His home is listed in the ASES’s (American Solar Energy Society) National Solar Tour of 2007. We took a look at this space age circa 1982 home.
Avenson is a huge fan of science fiction and had always dreamed of having his own space age “Jetsons” home with a flying car. While he has the dream home he doesn’t have the flying car. The highly energy efficient solar home rests next to Standley Lake.
When SERI (Solar Energy Research Institute), now called NREL (National Renewable Energy Laboratory), launched a national challenge to home builders in 1981 to build energy efficient homes; Avenson jumped at the opportunity to build his solar house. This program offered benefits to home builders and home owners by offering tax credits. At the time, he toured some solar homes around the Denver metro area and gathered ideas for his energy efficient solar home.
He wanted his home to be attractive, affordable, functional, and efficient. He learned that one of the biggest ways to reduce household energy consumption was to build a passive solar home. Passive solar uses the heat of the sun in the winter, but not in the summer. The home was built with the sun in mind, not the view of the mountains.
We began our tour on a hot summer morning in the backyard of Avenson’s home, where he explained the importance of situating the home to face southward. He discussed the passive solar design, his roof mounted weather station, and of course the photo voltaic panels (24 each at 4.7 kW per day) on his roof. This home is grid tied so he uses net metering where his PV provides all the electricity needs during the summer days. The excess electricity goes to his neighbors and then to the grid.
Avenson’s home may not be at net zero yet he continues to strive for that goal. He has no heating bills, since he designed the home to use passive solar (large windows on the south side and fewer windows elsewhere), thermal mass (river rock box 10 feet deep and brick walls release stored heat at night), foam insulation (used in the siding and foundation), and SolarSheats (heat collectors installed on the exterior of the home). The home has a gas furnace used only as a backup.
A calm and sultry female voice welcomes us at the double door entry way. Rex is the electronic watch dog of the house and monitors indoor and outdoor temperatures and weather conditions. She also controls light fixtures, electronics, outlets through Z-Wave, and window shades. This voice activated system required installing microphones, light and motion sensors, heat detectors, and thermometers throughout the home. Rex recognizes Avenson’s voice from anywhere in the home and is totally automated. She manages the interior climate even when Avenson is absent.
Cooling the home is performed by a swamp cooler installed in the attic. Swamp coolers are much more efficient than air conditioners. The entry way of the home offers a mud room and an interior door (double entry) which provides an air lock to keep cool air in during the summer and cold air out during the winter.
Lighting efficiency is one of the biggest ways to reduce energy consumption in the home. While Avenson exchanged out all the incandescent bulbs for compact fluorescents in the past, he now prefers to use light-emitting diodes (LED). LED’s use one quarter the amount of electricity than CFL’s. Windows and other natural lighting fixtures provide day lighting to reduce electrical use during the day.
Notice that the top south facing windows (see photo above) on the home provide day light to the interior. The windows are also triple pane with automated Mylar window shades. This is the same material used for tinting car windows. Avenson didn’t want to use low-emissivity (low E) windows in his home as it reduces the amount of radiant heat/sunlight coming into the home, which really defeats the purpose of having passive solar. He uses the blinds instead and Rex can control the radiant light entering his home. The blinds, when closed, are secured by magnets to lock out cold or hot air.
The home has had an energy audit and its HERS (“E star”) rating is 26 from a scale of 0-500. Avenson added that the average energy efficient American homes rate between 50-90 on the HERS scale today. The lower the rating the more efficient the home. Remember that his home was built in 1982 and is still more efficient than the majority of the homes built today!
Avenson stresses lighting and insulation to be the biggest components to saving energy in anyone’s home and it doesn’t have to be a SERI designed home. This includes caulking outlets, since outside air comes through them, and placing an insulating blanket around your water heater.
Avenson believes in having an “air tight” home to be the most energy efficient method. His home is constantly circulating air from his swamp cooler in the summer and the home’s thermal mass (heated by passive solar) to heat it in the winter using a circulating fan.
In addition, the clothes dryer is rarely used so he uses a clothes line on his back porch. His computer is a 15 watt system, which is much more efficient than any typical home computer system. So to sum up, Avenson’s electrical usage was reduced by using PV, switching out the light bulbs for energy efficient ones, turning off electronics (including phantom loads), a reduction in clothes dryer use, and taking advantage of day lighting features including Solatubes in closets and bathrooms. Remember that his gas bill is very low as he only uses it for hot water. His electricity bill went from an average rate of $85 a month down to $12 per month. Can you imagine paying only $12 per month for electricity? Some days in the summer the home is net zero! The electrical meter is actually running backwards!
Water conservation is also important in the home. The bathrooms have low flow toilets. The home uses the Metlunch hot water D’MAND system, which allows for less hot water waste and works from a remote control. He uses a front loading washer, which is much more efficient than a top loading machine. Avenson also recommends using smaller towels for showering, as they will require less water and energy to clean.
At the end of the tour the adventure ended with some scenes from Avenson’s cinematic inspirations Space Odyssey 2010 (2004) and Space Odyssey 2001 (1968). He has actually watched the movies frame by frame to learn more about futuristic inventions and ways to apply them into his own life. Avenson is a telecom engineer and while he may not see flying cars in the near future he states that there will be much more nano technology to come. He is also excited about the prospects of organic LED wall paper, featured in Space Odyssey 2001, to light up rooms instead of using lighting fixtures. This isn’t just science fiction.
Right now Avenson’s goal is to have a net zero home all year round and to continue to educate the public on ways to save energy. He states on his website, “Harvest the sun as much as you can to help the world become independent of fossil fuels.”
To learn more about Avenson’s home or to schedule a tour, check out his home’s live energy usage page: http://view2.fatspaniel.net/FST/Portal/SolSource/seri/HostedEndUserView.html
Want to learn more about net zero homes planned in our area? Check out Michele’s article “New net zero homes planned in Arvada”.
What’s new with Michele?
There are lots of great stories this week. This includes a story on solar cookers, the second part of the series on Clean Energy 101: Are hydro power and the nuclear option clean?, later a feature on a Colorado off grid resort, and Green Lifestyles 101.
If you have any suggestions, questions, or ideas please submit them to Michele Melio at: mspencr@ix.netcom.com.
A few video recommendations by John Avenson:
End of Suburbia
Kilowatt Ours
Crude Awakening
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