The 4,300 square foot "French Country" custom home featured in our story is a truly exceptional example of a growing trend in 21st Century home-building that uses "Green" or "sustainable" building practices and materials. The gorgeous home was built by Dallas,Texas-based Enviro Custom Homes. This house proves that one does not have to sacrifice traditional concepts of style to achieve ultra-modern results when it comes to energy efficiency and resource conservation.
The philosophical and market forces driving the "Green Building" movement in the United States are powerful and gain added strength with each new wave of electrical outages and water shortages.
If the power goes out, this home will still be humming along, powered by solar panels and back-up batteries that have stored previously harvested solar energy. The average monthly electric bill for this house is just $150 — about 40% less than a traditionally built home of the same size in the same area.
Very little city-provided water is needed to maintain the landscape, because the house has a 550 gallon rainwater collector that is used to maintain the plants and grasses chosen according to water-conserving "Xeriscape" principles.
How They Do It
Enviro Custom Home founders Barbara and Richard Harwood, and current owner Cathy Williams, advocate and put into action several basic and relatively simple principles in home design and construction:
* Strong emphasis on elements that reduce the heating and cooling load
* Increase comfort levels and reduce possible physical effects of chemicals that are used in building materials or home maintenance
* Minimal use of natural resources in order to have the least disruptive impact on the earth, incorporating natural materials, sunlight and green plants.
These goals are achieved by including the following features:
* Structural Insulated Panels (SIPS) or equivalent for framing
SIPS wall panels are 4/12 inches thick. Ceiling panels are 8 ¼ inches thick. Panels are manufactured with ½ inch oriented strand board (OSB) forming the exterior sides of a "sandwich" of expanded polystyrene. Polystyrene has exceptional insulating qualities, and the SIPS frame essentially creates an "icebox" effect, once all the pre-formed panels are attached to each other and the joints are foamed and glued, and the panels are attached to the foundation. According to the Structural Insulated Panel Association, SIPS buildings are more stronger, quieter, more energy efficient and draft-free than other, older building systems.
* Healthy Indoor Air Quality
New building materials often contain high levels of volatile organic compounds, such as formaldehyde, nitrogen dioxide, and other chemicals associated with paints and wood preservatives. Studies by the EPA found levels of about a dozen organic pollutants to be two to five times higher inside homes than outside, and that these high pollutant levels can persist in the air long after the building activity is completed. The builders counteract these effects by choosing materials that are contain few or no volatile organic compounds. They also use hard-surface flooring, such as patterned concrete and ceramic tile wherever possible.
* Passive Solar Heating
Passive solar heating is achieved by orienting the house and placing windows and eaves in such a fashion as to maximize the heating effects of the sun in the winter, and reducing exposure to the sun in the hottest parts of summer.
* Active Solar Systems
The use of photovoltaic panels to generate electricity is a key element in the overall energy efficiency of the "green" home. Depending on the size of installation, photovoltaic panels can serve as a supplement or even a replacement of "grid" electricity. In the Homan home we featured in our story, the thin solar panels can provide virtually all of the home's 110 volt electric needs. A bank of batteries is connected to the system for storing power, as well.
* Proper sizing of HVAC equipment
Because the house is extremely well insulated and uses passive solar heating, natural wind ventilation and various other energy-saving methods, the "tonnage" of HVAC equipment needed to comfortably heat and cool the house is less than would be required for a similar-sized house that does not contain these features. These calculations are done in the design phase and result in significant savings by ensuring that the owners do not purchase, and install more HVAC capacity than the house actually needs.
The Homan home has a geothermal pump that further enhances the energy efficiency of the HVAC system by using the earth's temperature to reduce the heating and cooling required by the HVAC system.