Design Principles
House Design
Abundance Ecovillage Corporation doesn’t build homes, but we do assist lot owners in design for energy efficiency. We love the "not so big house" design philosophy. Small homes are encouraged (we don’t have any minimum size) and the maximum size is 1700 square feet on one floor. House sizes range from 3600 sq feet to 600 sq feet. House design at the ecovillage is a team effort made up of the following – the homeowner and his/her designer/architect, the builder, the HVAC, plumbing, and electrical contractors, plus other consultants in geothermal, passive solar design, daylighting, and Maharishi Sthapatya Ved.
Starting summer 2007 builders Steve Vessey and the Greenfields are building energy efficient homes for sale at Abundance Ecovillage. Steve Vessey has already completed 2 beautiful energy efficient homes at Abundance Ecovillage, see Village Progress for pictures of these homes. See Becoming A Villager for contact information for builders Steve Vessey and the Greenfields.
Here is a link to a Wiki on efficient energy use created by a student in MUM's Energy Course. This sight gives information about building design, choosing appliances, reducing electricity use, etc.
Heating and Cooling
It is important that the heating and cooling systems do not require lots of electrical energy at the worst times of the year (a cold, windless night preceded by a cloudy, windless day, for example). Currently three of the five homes here are heated with wood stoves with LP gas for backup. We hope to have a methane digester up and running soon.
Earth Tubes
Cooling provides a special challenge for off grid homes in our climate. We sometimes get weeks of temperatures with highs near 100 degrees with fairly high humidity. Conventional AC systems (compressor driven expansion cooling systems) take lots of energy and for most of the year it is too humid to permit effective use of direct evaporative cooling. Larry Larson has designed and installed earth tubes in 4 of the 5 houses at AEV. He has extensive experience in earth tubes for cooling in humid climates (200 homes in Michigan and Texas). The earth tube systems only require a small fan (25-50 watts) to provide cooling and dehumidification in summer or fresh air tempering in winter. Systems use 4 parallel lengths of 8-10 inch flexible corrugated drainpipe, buried 8 feet in the ground. A slit is cut in the bottom of the pipe for condensation drainage, the pipes are laid in sand, and the area below the pipes is drained to daylight. The intake end of the pipe surfaces to a small cabinet with air filters, and the air exits into the basement. Often, the earth tubes will use the fan from a small high-efficiency furnace to distribute the air and to provide back up heat in winter. In very cold conditions, an air-to-air heat exchanger would require less back up heat to provide fresh air than the earth tube system. On a 100-degree day, I have seen 70-degree air exit the tubes into my house. At this point, the air is saturated (100% relative humidity), but by the time it mixes with the air in the house it has risen to 80 degrees and the relative humidity has dropped, creating a pleasant contrast to the 100 degree outside temperature. We have never had any problems with mold, excess condensation, or radon in these systems.
| Larry Larson putting in earth tubes for Sandy Rando's home in Abundance Ecovillage. |
Solar Hot Water
Home owners can choose to install solar hot water for their own household use. Solar hot water heaters provide 90-100 percent of the energy required to heat hot water in the warm months. They even work in the winter and reduce the amount of LP gas needed for heating water. Kevin Hopf has installed systems in the AEV homes, including new efficient tubes that heat water even on overcast days.
Passive solar design
The homes here use passive solar design to minimize the amount of heating and cooling needed. Intelligent placement of windows allows the houses to be more energy efficient. More windows on the south allows the winter sun to warm the house on sunny winter days. A sufficient overhang keeps the sun out in the summer. Fewer windows are placed on the east, north, and especially on the west. If the window area on the west is minimized the house will be much easier to keep cool in the summer.
Daylighting
Proper placement of windows also allows houses to use daylighting which is a much more pleasant light to live in and it saves energy.
Insulation
Well insulated homes require less energy to heat in the winter and stay cooler in the summer. They also are quieter inside.
Wise Use of Electricity
To conserve energy is not to suffer - it is simply to use resources more productively. The houses are designed to perform all the functions expected from electricity today (lights, computers, stereos, TV, refrigeration etc) but use a combination of design (day lighting, for example) and the most efficient appliances available to cut electrical consumption to 1/3 to 1/10 of a typical home. Home lighting uses compact flourescent light bulbs. TV's, VCR's, DVD players, computers, etc. are plugged into power strips and shut off when not in use to eliminate phantom loads.
Water
Two sources of pressurized water are delivered to each home. The first comes from the roof catchment, is stored in underground tanks, ozonated, filtered and treated with UV light. The second is from ponds. The pond water runs through a sand and gravel filter, a 5-micron cartridge filter, and a carbon filter. The rain catchment water is higher quality and suitable for bathing and washing. The filtered pond water is suitable for uses like flushing toilets and watering plants. Further purification of rain catchment water for human consumption is up to the homeowner and could include ceramic filtering, reverse osmosis and further UV treatment. Every house that has been built so far has a different system for drinking water purification.
Local Lumber
Most of the lumber available in local lumberyards is from the Pacific Northwest, and if you have any friends there you know they are not happy that we are cutting down their forests. Iowa can grow some of the best hardwood forests in the world. The first home, the Walton house, used locally milled (biodiesel powered) woods for 95% of the lumber in the house. Woods include cottonwood for framing, oak and walnut (black walnut is very common here). The cost was less than for conventional lumber, not counting the time spent organizing the local lumber project.