As in any other facet of the construction industry, things are greening at Habitat for Humanity, too. Drury University's Sustainable Habitat House was completed in Springfield, MO this summer, and has won recognition as the first-ever LEED Platinum-certified Habitat project.
"It's as green as it gets," says Traci Sooter, AIA, Drury associate professor of architecture, of the home that achieved the highest level of environmentally responsible standards established by the USGBC.
A learning experience
Architecture students designed the home for new owner Amy Pinegar and her children as part of Sooter's design/build course. Volunteers spent more than 5,000 hours working on the house and Sooter used every opportunity to teach them about the home and the practice of sustainability.
"My students learned how to take a plan and construct it full-scale. And they saw how a community can come together to achieve a common goal; they'll take that into their careers," says Sooter.
"It was a great experience for all of us in creating an affordable, sustainable residence," said Anna Codutti, director of development for Habitat for Humanity Springfield.
Solar heat integrates with mechanical system
On the home's roof is a 30-tube vacuum solar array that feeds a heated glycol antifreeze mix directly into an 80-gallon, twin-coil indirect water heater. The glycol solution circulates in the tank's lowest coil, exchanging heat with the large volume of contained domestic hot water which in turn shares its heat with the uppermost coil which supplies heated fluid into the home's two radiant heat zones.
During summer months, the vacuum tube array provides temperatures of 160°F, or higher. During winter months, the solar array may heat the glycol solution to about 110°F. Data from the past several months show that the solar heat system will provide 60% to 70% of all domestic water needs.
"We knew that radiant heat with solar tie-in would be the very best, most comfortable and efficient means of keeping the family warm and cozy inside," said Alex Green, director of research and development at Watts Radiant.
Two radiant heat zones were installed in the house:
- The first zone is comprised of four 250-foot, 1/2-inch loops of Onix EPDM synthetic rubber tubing encased in the home's insulated concrete basement slab. The loops circulate fluid at about 110°F into the 900 square foot slab.
- The second zone is made up of two 300-foot, 1/2-inch loops of RadiantPEX cross-linked polyethylene plastic tubing that feed warmth to the 400 square-foot upstairs area of the home. These loops were attached to the upper level's subfloor by joist bay staple-up with extruded aluminum plates.
As backup heat for the domestic water system, a squat, 40-gallon electric water heater was installed. In addition, an electric boiler was installed as backup heat for the radiant heat system.
Watts Radiant also provided a solar HydroControl panel, radiant heat manifolds and aluminum heat dispersion plates.
"This was an especially rewarding experience for Drury students and staff alike," concluded Sooter. "We look forward to our next hands-on, green-build project."