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Green Building Sourcebook

Affordable green building design

Why build "green"? To improve energy efficiency, conserve resources, and improve indoor air quality.

Energy Efficiency

Tight "Building Envelope" means insulation, windows and doors are as air tight as possible. Since there isn't the typical influx of outdoor air, this does require additional ventilation to create air circulation and fresh air.
On-Demand Hot Water Heaters heat water only when needed. There is no tank with a constant supply of hot water. Instead, the water passes through a heater that quickly heats the water as it passes through. On-Demand Hot Water Heaters do limit the number of concurrent uses to just one. (Can't take a shower and run the dishwasher.)
Efficient Wall Systems include a reduction of the amount of wood needed to frame the house. Wood does not insulate well so putting studs 24 inches apart rather than 16 inches allows for more insulation. Insulated Concrete Forms, or ICFs, are a complete wall system made of concrete and Styrofoam insulation. The walls are 6 inches thick rather that the typical 4 inches. The concrete holds warm air in during the winter and keeps indoor air cool in the summer.
Heating and Cooling. Most houses use a heat pump to provide both heat and air conditioning. The higher the SEER (Seasonal Energy Efficiency Rating), the more efficient the system. A variable speed fan on the heat pump also improves efficiency. A geothermal heat pump takes advantage of the stable temperature of the ground to improve efficiency.
EnergyStar Appliances. Appliances with an EnergyStar rating have a high efficiency and thus reduce costs. EnergyStar is a program of the federal government.
Florescent Lighting. Provides illumination at a lower wattage than incandescent lights and typically last longer. Florescent bulbs are particularly practical in a hard to reach receptacle.

Resource Conservation

Water especially well water can be effectively conserved using low flow fixtures, and in some of the houses developed in the region, a cistern (an underground tank for storing rainwater) collects rainwater from the roof of the house and stores it in the cistern for use in flushing toilets. Additional plumbing is needed but over time more than pays for itself. On demand hot water heaters also conserve resources.
Reused and Recycled Materials include concrete, (demolished concreted can be used in poured concrete structures such as ICFs), wood flooring, flooring tile, carpeting, and insulation (containing recycled newspaper). Recycled plastic is used in the manufacture of roofing shingles and is being used in AHIP's Esmont homes.
Exterior Siding. Vinyl siding is typically used in affordable housing but it is a oil-derived product made with polyvinyl chloride (PVC). HardiPlank siding is a concrete based product and is more durable than vinyl, its manufacture is less polluting and less wasteful of non-renewable resources. It is more attractive and sturdier as well.
Flooring. More imaginative flooring includes cork and bamboo. Rather than harvesting old growth trees, cork is more plentiful and bamboo grows quickly and can be harvested every 4 years.
Minimize Construction Waste. Wood, cardboard, metals, drywall, plastics, and shingles can all be recycled. Habitat for Humanity manages a store on Preston Avenue, collecting used but serviceable construction materials and architectural artifacts. It is open to the public.

Air Quality

Garages should be completely sealed from living space, preferably with an exhaust fan, which can be powered with a motion-detector.
Fuel Burning Fireplaces, including those using gas are to be properly vented and space heaters are to be avoided.
Moisture Control is important to minimize mold and mildew and primarily involves protecting living space from the home's foundation.
Ventilation is particularly important in air tight homes. Ceiling fans, EnergyStar bath fans, kitchen range hoods vented to the outside, and whole house fans are examples of good ventilation controls.
Off-gasing of carpeting and particle board (containing formaldehyde) is a problem, particularly right after installation, for allergy prone residents. Carpets should be made of natural fibers and particle board should be formaldehyde free.
Fiberglass insulation has been identified as a potential carcinogen and irritates the skin. Insulation made of cellulose (a paper product) is a better alternative.