Super Insulation: Your Energy Hero

by Fred Horch, Principal Advisor, Sustainable Practice.

Super-insulated homes can be heated with a hair dryer, even in Maine’s climate.

Heating a well-designed new home with a gas-burning furnace or boiler is like lighting birthday candles with a flamethrower. That might seem a little extreme, but consider the fact that a 2,000-square-foot new home built to Passive House standards in climate zone 6 (northern New England and the upper Midwest) has a peak heat load of less than 2,000 watts. You can buy electric hair dryers that use that much power.

The better insulated your home, the easier it is to keep your family comfortable.

Insulation (starting with air sealing) is the key to achieving high levels of home energy performance. Older, poorly designed homes with inadequate insulation require fifteen times more power to heat. A homeowner might use an online boiler size calculator to ask, “What size boiler do I need for a 2,000-square-foot home in climate zone 6?” A typical answer would be a gas-burning boiler rated at 100,000 to 120,000 British Thermal Units per hour (29,307 to 35,168 watts).

A high-performance home (built to Passive House standards) gets 30 minutes of comfort per kilowatt hour of energy used to heat it on the coldest day of the year. A 48 kWh home battery system (four Tesla Powerwalls) can keep a well-insulated house…