the technical side to affordable green homes Here’s what one nonprofit — the Asheville Area Habitat for Humanity — makes homes green in the program.
Indoor air quality
Site Development
• Low-VOC carpet and recycled content carpet padding
• Tree clearing is done per lot rather than over the entire subdivision with an attempt to save border/backyard trees • Trees and brush are ground for mulch, or saved for firewood • Jobsite recycling of cardboard, aluminum and beverage containers • Drought-resistant and native plants used in landscaping
Heating/cooling, appliances, energy usage
• Low-VOC6 Advantech subflooring • Formaldehyde-free insulation • Recycled newspaper cellulose wall and ceiling insulation treated with natural borate insecticide • Range hood and bath fans directly vented to the outdoors • Direct fresh air intake for the heating/cooling system • Third-party certification for all vent performance • Water based, low-odor interior wall primer, paint and exterior wood stain
• Duct work is mastic-sealed and third-party certified for leakage less than 3 percent • Air flow to each room is balanced and third- party certified to ensure comfort • High-efficiency (15 SEER1/8.5 HSPF2) heat pump exceeds ENERGY STAR requirements • High efficiency (.95 EF) water heater exceeds ENERGY STAR requirements • ENERGY STAR-rated refrigerator
Green materials
• Engineered I-joists, main girder, and band joist8 rather than dimensional lumber for floor framing system • Engineered roof trusses rather than dimensional lumber for all roof framing system • Compact florescent bulbs used in 95 percent of light fixtures • Non-tropical birch plywood underlays vinyl flooring • Non-tropical recycled wood content interior doors
• ENERGY STAR -rated low water usage washing machine
• Surplus building materials are either saved for future houses or donated to the Habitat Home Store for resale
• Low-flow kitchen and shower/bath faucets • Third party certification and guarantee of the average monthly energy consumption for heating and cooling ($25-$35 per month, depending on square footage)
Other notes
• Progress Energy discount on electric rates
Building envelope
• Heating Season Performance Factor measures the heat pump’s heating efficiency. An HSPF rating of 9 is ENERGY STAR level (lower numbers are more efficient)
• Sealed exterior wall plates and outside corners
• Energy Recovery Factor measures water heater efficiency. An ERF of .90 is ENREGY STAR level.
• Flexible gasket insulation around windows, exterior doors, and between the floor system and foundation
• R-value refers to the resistance (R) to heat flow of a product and measures its insulating value.
• House tightness certified to less than .30 cubic feet per minute (air pressure)
• Oriented Strand Board (OSB) is a composite material made of compressed and glued scraps of wood that would otherwise be discarded as waste.
• Vapor-permeable, draft-stopping housewrap
• Insulating (R-34) styrofoam wall sheathing rather than OSB5/plywood on most exterior walls • 12” raised heel trusses to allow full insulation value (R38) in the attic • Insulated (R-38) and weatherstripped scuttle hole rather than uninsulated pull-down stairs • High efficiency vinyl windows that exceed Energy Star requirements
• SEER is a measure of a heat pump’s cooling efficiency; 12 SEER is Energy-Star level
• Volatile Organic Compounds are chemical vapors released by many manufactured construction products such as paint, cabinets, and composite wood products. Those with chemical sensitivities or respiratory problems sometimes have negative reactions to VOC exposure. For more information, visit healthybuilt.org or advancedenergy.org.
• 2-foot roof overhangs that provide solar shading
WNC Green Building Council
wncgreenbuilding.com
WNC Green Building Directory
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