Passive home on cutting edge

OLYMPIA – A home without a central heating system that’s designed to reduce home heating costs by 75 percent or more is under construction on Marion Street.

It’s called a passive house – the first of its kind in South Sound and only the second in the state using an architectural design hatched in Germany about 15 years ago.

The home achieves its high energy-efficiency rating through extensive insulation, airtight construction that eliminates heat loss, and a high-tech heat-recovery and ventilation system that maintains air quality.

In a passive house, a hair dryer, candle or coil from the water heater could be the heat source for the house, said Tessa Smith, home designer and co-owner of the Artisans Group, which designed and is building the home for DT and Kim North and their two sons.

The Norths, both vocational rehabilitation counselors by trade, wanted a home that really took energy efficiency to the next level. They were impressed by the performance data from existing passive homes.

“We have a lot of people stopping by and asking questions about the house,” Kim North said.

Of particular interest to DT North was the 15-inch layer of expanded polystyrene that sits under the concrete foundation of the home, sealing it up from the bottom.

“It felt like they were building an ice chest,” North said of the insulating qualities of the foundation.

The kitchen, dining area and living room, all interconnected and called the “great room,” feature extensive, south-facing windows to capture solar heat passively. The house is built so that photovoltaic units can be tacked on, if desired.

“If energy costs go up 100 percent, we can always slap on a couple of solar panels,” North said.

The house is under construction next door to the Norths’ older, energy-inefficient home. Their plan is to tear it down and salvage as much of the building material as possible for reuse.

Smith estimates it’s about 7 percent more expensive to build a passive house compared with one built to code. But the energy savings should make up the difference in about 4  1/2 years.

The Artisans Group has two other passive houses under construction and 12 projects in various stages of design and permitting, Smith said.