Building technology is improving every day, but if it’s a super energy-efficient dwelling you’re after, the tools are already well at hand.
Once a year, the Northeast Sustainable Energy Association organizes a green buildings open house where energy nerds like myself can see the latest in home efficiency.
The homes, which are both new construction and renovations, show that builders, architects, and homeowners have unlocked the code for making buildings dramatically more energy efficient than your typical construction. The question now is whether green building techniques and products will remain on the fringe or become more mainstream.
Common ground on green buildings (photos)
In a nutshell, the key is to build a house that’s appropriately sized and very well insulated, said Doug Storey, the managing partner of Two Storey Building and builder of one of the houses on last week’s tour.
If you create a building with a very air-tight and heavily insulated envelope, the heating and cooling needs go down significantly. That not only saves money on monthly bills, it also allows builders to install smaller, less expensive heating and cooling equipment.
“People ask me what the first thing they should do to be more energy efficient [with new construction], and I say it’s to build smaller,” Storey said, noting that the median house size in the U.S. has been creeping down. “The consumer is not just going for bigger these days.”
Could you get to a net zero-energy house? Cutting-edge designer builders have been able to make net zero-energy houses even in chilly New England using a combination of on-site solar energy and air-source heat pumps, which run on electricity. These ductless systems, which do both heating and cooling, work best above about 40 degrees and better suited for smaller homes, Storey said.
The house in Concord, Mass., which Storey is building is too big, at 3,800 square feet, for air-source heat pumps. Instead, it has a similar geothermal ground-source heat pump which, combined with solar photovoltaic panels, will make it consume much less than a similarly sized house.
Deep energy retrofits
What about existing houses? Some of the same techniques are being applied to get 60 percent or more improvement in energy efficiency. There were 32 deep energy retrofit projects out of total of 500 homes on display in last week’s tour, underscoring how it’s still specialized skill and relatively expensive approach.
Boston resident Edith Buhs and her husband decided on a deep energy retrofit when they needed to reshingle their Jamaica Plain three-family home.
