PULLMAN – When most people think of building a sustainable house, they think of throwing a few solar panels on the roof and buying an “environmentally friendly” dishwasher.
For Dyonne Davidson, WSU Capital Planning project manager, constructing a “green” home meant starting from scratch – solar panels included.
“One of the exciting things about moving up here was the possibility of designing and building a ‘green’ home,” said Davidson, who came to Pullman from Portland, Ore.
She said her main goal in designing the house, located on Pioneer Hill, was to reduce the energy consumption caused mostly by heating and cooling.
Homes and other buildings use 70 percent of the state’s electricity and are responsible for more than 30 percent of Washington’s carbon dioxide emissions, according to a bill passed in the state Legislature.
The design features of Davidson’s house potentially will cut her energy use by 70 percent.
The 2,800-square-foot four-bedroom house will be built primarily of insulated FasWall blocks, made of 85 percent reclaimed wood chips and 15 percent Portland cement. They will help the house maintain a comfortable temperature throughout the day.
The main floor will be polished concrete with embedded hydronic heating tubes. Underneath the concrete lie 150 tons (two feet deep) of sand. The sand plays a key role as a “thermal battery,” retaining and storing summer heat for use throughout the winter.
Roof-mounted solar panels will heat water that circulates through hydronic tubes in the sand. The insulated sandbed will warm the house from the bottom up, continually recharging on sunny winter days.
Davidson said the sand cost around $3,000, which ultimately will be offset by reduced heating bills.
Water heated by the solar thermal panels will be available for domestic use before it is directed for heating purposes. A backup on-demand hot-water heater will be available during extended cloudy periods. But the sandbed is expected to bridge solar lulls for heating the home most of the time.
The house will not have an electric air-conditioning system. Instead, the design will maximize passive cooling.
Windows, strategically placed on the south side of the house, will have overhangs to provide shade from hot summer sun. Rays from the low winter sun will penetrate deep within to warm the floors and walls.
Ceiling fans and clerestory windows on the north side will aid cross- and stack-ventilation to cool the house.
Davidson chose a metal roof so, when it rains, the water coming off the roof won’t grab any toxins that asphalt shingles typically contain. The metal roof also will last longer than asphalt, reducing the impacts of landfill waste, she said.
Many materials, both interior and exterior, were chosen for low-maintenance upkeep and long-term durability, which Davidson said she finds compatible with her philosophy of sustainability.
Davidson admits that building “green” is still more expensive than building a conventional house, but she anticipates it ultimately will be cost-effective.
“I’ve been an advocate of sustainable building since my college days,” she said, “and I decided it was time to ‘walk my talk.’”
“Check back with me when it’s actually built, and we’ll see if it’s working as hoped,” she said.
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Dyonne Davidson with her daughter Isabella. |
