A small house in Vermont goes above code to cut energy bills by more than half.
Synopsis: Northern Vermont can endure brutal winters. Built beyond code standards, this 1500-sq.-ft. house ran up just $767 in its 2010 electricity and natural-gas bills. Dunbar Oehmig, president of the firm that built the home, describes how SIP construction and attention to air-sealing helped to create a supertight house. Additionally, the house uses a high-efficiency, modulating, condensing boiler for hot water; a wastewater heat-recovery device; fluorescent and LED lighting; a heat-recovery ventilator; and Energy Star appliances. Among the house’s durable, low-maintenance materials is a green roof assembly with a lightweight growing medium over a filter fabric and root barrier.
When I tell people what it costs to heat and light the house my company recently built in Burlington, Vt., I don’t think they believe me, and I can see why they’re skeptical. With natural-gas and electric bills totaling $767 in 2010, this home’s energy costs less than half of what you’d expect to pay for utilities in the same house built to code-minimum standards.
Even more surprising is that this house cost only about $16,500 more than the same house built to code minimums. If energy costs stay the same, the energy upgrades should pay for themselves in a little over 16 years. Of course, the payback will be quicker if energy costs rise as predicted.
Tight shell reduces heat loss
The SIP construction and the attention to air-sealing by our crew and our insulator created a supertight house. The final blower-door test by the LEED certifier came in at 150 cubic feet per minute at 50 pascals (150 cfm50). At the time, it was the tightest house (by a factor of two) ever tested by the certifier.
In most weather, the supertight shell means the heating load is met before the boiler shifts to a more powerful but less efficient firing mode.…