Saturday, June 30, 2012

Keiser Builds Net-Zero Homes for Maine Subdivision

Keiser Industries, the Oxford, Maine modular home factory, had one of their net-zero homes showcased in a new community, Brackett Estates in Wells, ME as the model home.

Designing and building a net-zero home for the Maine market is tough as the winters are bitter cold and heat is like gold.  But CB Builders along with JP Ware Design decided that the best way to get optimum results was to go modular.

Using energy-related features and quality materials, the developers can justify a slightly higher price per square foot that many new home buyers don’t seem to mind if they can get the results they expect.

Homes that can make as much energy as they take sometimes are called net-zero, because there's a net gain of power over a year. Such homes tend to use solar electric and solar hot-water panels, and sometimes wind turbines, to generate power. In most cases, electricity is fed into the utility grid.

Zero-energy homes are becoming more common. The next step is zero-energy communities, several of which are rising across the country. The idea is to lower prices by spreading design costs among many homes.

The model home here has a range of features to achieve zero energy:
  • The walls are a foot thick and have an insulation value of R-40, nearly twice that of a typical new home. The roof is insulated to R-60.
  • Windows contain a heat-blocking gas within three panes of high-performance glass. South-facing glazing is positioned to welcome winter sun, and shaded by overhangs that repel high-angle summer rays.
  • The building is warmed in winter and cooled in summer by a high-efficiency electric heat pump called a mini-split. Similar heat pump technology warms water with a so-called hybrid water heater in the unfinished, daylight basement.
  • Nearly every crack and seam is caulked and weather-stripped, making the building so tight that a special ventilation system is used to provide fresh air. One reason the home is so well sealed is its modular construction. 
  • It's what's on the roof that makes the home net zero. The southern slope is covered with solar electric panels. They add about $17,000 to the total cost of the home, after tax credits.

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