Sep 12, 2014 6:16:00 PM
Sep 4, 2014 2:31:12 PM
JUST OUTSIDE SAVANNAH on an organic farm developed for a new zero-energy lifestyle sits a modular home that produces as much energy as it uses. The home was built in a factory, which reduced resource use, kept costs in check, and expedited the schedule.
The house, dubbed iHouse by Clayton Homes, the company that designed and built it, offers a host of sustainable features, but it was the house’s energy efficiency that attracted Charles Davis, president of The Earth Comfort Company.
He built an iHouse for himself, which also serves as a model home. He handled all the site work and added a geothermal heat pump and 3kW PV panels.
“I chose the house for its thermal envelope,” Davis explains. “I tell everyone if you start with good, tight envelope then you need less geothermal and solar. I put just enough solar on my house to cover peak usage.” He takes advantage of Georgia Power’s reduced rates for off-peak power use by, for example, charging his Chevy Volt at night for 1 cent per kWH. And he uses an energy monitor connected to his iPhone to monitor the energy use of each appliance in his home. “The most important green product is the energy monitor, which allows you to see the actual wattage by each appliance and number of watts of power produced by the solar panels, and the number of watts sold back to Georgia Power,” Davis says.
Aug 26, 2014 11:19:09 AM
DUBBED "PASSIVE HOUSE IN THE WOODS", this project takes energy efficiency far beyond the experience of most residential builders. It’s a bleeding edge design, a strikingly modern structure that produces 65% more electricity than it needs. It also has an interesting back story.
“The client’s wife was ill with cancer as we were planning this home,” notes architect Tim Delhey Eian.
“She passed away before construction began, and we ended up changing the design to a much more vertical plan.
“We chose ICFs deliberately, as a pretty fail-safe construction method,” he adds. “I had a good grasp of Passivhaus concepts, because I grew up in Germany and completed the training there.”
Although the systems in this home are familiar, this project takes them to a higher level. The ICFs, for example, extend below grade, and are augmented with a commercial-grade EIFS system that includes 11” of EPS foam above grade—making a wall 22” thick with an R-value of 70.
“We tried to get the North American branch (of Sto Corp.) to provide the details we wanted, but the deal fell through,” the architect notes. “They only offered this version of EIFS in Europe. It puts all of the water management on the exterior. They’ve now started offering it in the U.S.”
The flat roof includes 14” of polyisocyanurate foam, achieving R-95, and the windows and doors, imported from Germany, are triple-pane, low-E coated, with insulated frames. They have an installed R-value of 8. By comparison, a typical wood or vinyl-framed, dual-pane, low-E window achieves only about R-2.
The slab also sits on 12” of EPS foam (R-60), and the garage doors are insulated as well, so the overall heating demand for the home is extremely low. In fact, it has no furnace and no fireplace, despite the cold climate. The home, designed for a heating load of just 3,000 W, relies on passive solar plus a modest ground loop geothermal system, with a back up of electrical floor mats from Nuheat. A super-efficient HRV provides ventilation to the whole house, with minimal loss of BTU.
Along with the 4.5 kW PV panels, the house has a 40-sq.-ft. hot water solar collector that provides 90% of the home’s hot water demand. A small electric hot water heater provides the rest.
The architect notes that by monitoring the home’s performance during the first year, the team was able to identify hidden energy wasters. “For instance,” he says, “we now know that the well pump was using a lot of energy—12% of the home’s consumption for a year. That was easy to improve.
“At the same time,” he adds, “some of the appliances out-performed our original estimates, in part because they weren’t used as much as expected. But we’re now extrapolating from the lifestyle impacts.”
Too often, notes the architect, home owners look at the aspects of a home that are not important—things that “are really going to go down the drain.” Not so, with this house, he says. It’s a project that ultimately gives the owner freedom—so “he won’t owe monthly bills to anyone.”
Aug 22, 2014 4:56:41 PM
UNDER NORMAL CIRCUMSTANCES, it would be hard to imagine a home on this site, high atop a cliff, surrounded by breathtaking views. But neither this home, known as the Zero Energy Idea House, nor its
architect, are of the average variety.
“It’s self-evident that this design is saying ‘I’m a different kind of house,’” says architect David Clinkston. “That was the intention—that you see the green roofs, PV panels, solar hot water panels and vertical axis windmill. These are all visible from the road. A ‘green wall’ at the main entrance (to reduce afternoon solar gain) is another clue that all is not ‘normal’ with this house.” The wall is a galvanized steel grid that will provide privacy when vines grow over it.
Not every aspect of the home’s infrastructure is obvious, of course. The structural insulated panel (SIP) structure sits atop concrete grade beams that thrust back into the steep slope, and the below-grade wall at the back of the house was poured into ICFs.
The house is heated with a Warmboard radiant floor system—wood panels coated with reflective aluminum.
“That aluminum skin is thick,” Clinkston says. “with grooves that direct the heat exactly where you want it.”
The architect took the owner’s interest in “seeing the bones” of the home seriously, specifying a steel frame as the carriage for the SIPs.
Aug 20, 2014 11:20:00 AM