Built-in community. Pleasant Hill cohousing demonstrates innovations in sustainability.

Cohousing communities balance the traditional advantages of home ownership with the benefits of shared common facilities and ongoing connections wit neighbours. The communities consists of private dwellings with their own kitchens, living-dining rooms, and so on. Residents also have common facilities, such as a dining room, a community kitchen, lounges, meeting rooms, a laundry room, recreation facilities, a library, workshops, or a childcare area. The typical cohousing community has 12 to 40 attached single-family homes arranged along a pedestrian street or clustered around a shared courtyard. By sharing common facilities, residents often cut down on the energy, resources and overall space required to house, feed and provide amenities for families. Cites an example of 12 families moving from single family homes having realised an average 75% drop in their annual energy bills. The Pleasant Hill community reduces energy use by having no electric air conditioning, in an area with over 1,000 cooling degree days. Passive techniques are emphasised. There is extensive use of window shading and cross ventilation, wide overhangs, a Polar ply radiant barrier which greatly reduces solar heat gain from the roof, corrugated metal roofing, dissipating heat rapidly and allowing for natural ventilation, low-e windows, thicker and denser gypsum board which adds a thin thermal mass storing solar energy in winter and allowing night cooling in summer, lightweight concrete floors. Other passive heating/cooling techniques non-standard in production houses were: extensive natural lighting, dual-purpose water heater; efficient water fixtures; efficient lighting; wet-blown cellulose insulation providing insulation levels of R-22 in the walls and R-38 in the ceilings; perimeter insulation to guard against slab edge heat loss. Other features are based on the philosophy of 'smaller, simpler, less' - no refuse disposal to encourage recycling; no fireplaces to aid air sealing; and the houses are much smaller than the average US home. Efficient, open plans and the large shared common house allow for an average private unit of 1,230 ft2. The community goals of sharing also help reduce car trips and redundant appliances, e.g. use of lawnmowers. The common house is designed with a passive cooling tower.