In December 2013, an ice storm caused an extended power outage in Maine, leaving many residents scrambling to keep their pipes from freezing. But even with no utility electricity for five days, below-freezing temperatures, primarily overcast conditions, and no supplemental heat, the homes at Belfast Cohousing & Ecovillage (BC&E) lost only 2?F a day, on average, for a total drop of 8?F to 10?F. Nearby homes, by contrast, were below freezing after 24 hours.
Although the homes aren't certified, the Passive House Institute US standards guided the design process. A southerly orientation; generous south-facing glazing; triple-pane windows and doors; lots of insulation; airtight construction; and a compact footprint resulted in a 90% reduction in the energy used for space heating compared to the average house. The homes share walls, reducing the exterior surface area and heat loss to the outside.
Full article is available here: http://www.homepower.com/articles/home-efficiency/project-profiles/near-net-zero-community-scale
