ZED | Zegarra Environmental Designs

Net Zero Home

Imagine a home that produces as much energy as it uses. This was the dream of Eric Doub founder of Eco Futures Company, and it wasn’t until 2004 that he and his family moved into their dream home a model that may represent how people will build their homes in the future…

The Showhouse That Sustainability Built
by Barnaby J. Feder

Eric Doub knows the difference between talking about building a green home and living in one: more than 2,600 energy-conscious visitors have traipsed through his model home in the last two and a half years.

Four years ago, Mr. Doub, the owner of Ecofutures Building in Boulder, Colo., was one of a growing number of builders intent on designing environmental sustainability into new homes and retrofitted projects. But clients willing to go all out for energy-efficient design and materials were scarce. And on a personal level, certain restrictions in the north Boulder development in which he and his wife, Catherine Childs, lived with their two young children hampered his ability to practice what he preached.

Then Ms. Childs discovered a large lot nearby where they could build their dream house – a house to prove that comfort, and even touches of luxury like a hot tub, did not have to be sacrificed to do right by the environment.

The $1.38 million project (including the land purchase) became a huge financial gamble. Mr. Doub had to cut loose 10 employees – 40 percent of his work force – and Ecofutures took on debt for the first time. But by late November 2005, the family was able to move into the five-bedroom, two-story model home they named Solar Harvest.

It used available technology and, when possible, salvaged materials. Mr. Doub bought 12 used solar panels to heat water for the heating system; the 6,000-gallon underground hot-water tank came from a dairy farm.

Some of the biggest benefits came from choices that did not cost money per se, like having the front of the house face south to take maximum advantage of the sun. But other choices, like installing superinsulated windows and solar electric roof panels, added 8 percent to the cost, Mr. Doub said.

It did not take long for the gamble to begin paying off. In its first year, Solar Harvest fed enough energy into the local power grid during sunny spells to offset the cost of all the power it used other times. A copy of the $8.45 check that Xcel Energy, the utility, sent to settle 2006 accounts sits framed on the dining room table.

Mr. Doub especially enjoyed the tour he offered to 15 local land-use officials one day in early February 2007, when the temperature outside read just about zero. As usual, the indoor temperatures ranged in the high 60s despite the lack of any heat source other than the water tank and air circulating from the tightly insulated sun porch.

Even better, the home began attracting clients like Ronald M. Abramson, the president and chief executive of NexGen Energy Partners, an investment group focused on renewable energy projects, which Mr. Abramson recently moved from Maryland to Boulder. He worked with Mr. Doub for six months to develop plans for a 7,000-square-foot home for him and his family on a stretch of prairie near Lyons, not far from Boulder.

“We wanted to build the most environmentally responsible home in the country,” Mr. Abramson said.

Mr. Doub’s design for the Abramsons includes a combination of wind and solar power that is expected to generate 80 percent more energy than the house will require when it is finished early next year. And, with strict attention to the materials used and their environmental impact, the Abramsons think they can balance their carbon dioxide emissions and reductions.

Carbon neutral or not, the Abramson home is the first to meet new Boulder County regulations that set a sliding scale of permitted energy use, based on size. At the top of the scale, all new homes of more than 5,000 square feet must be energy neutral, generating as much as they use. County officials credit Solar Harvest with drawing support for the new regulations.

“We needed to be able to see some homes that were close to net-zero energy in Boulder County,” said Will Toor, a county commissioner. “Eric’s was the first, and that helped convince people it was feasible at a modest additional cost.”

Mr. Doub said that the smaller the home, the more challenging it can be to achieve a zero energy design because of the higher ratio of walls to interior space. Thus, Mr. Doub said, his work is in some respects less impressive than the single-story 1,130 square foot zero-energy home Habitat for Humanity built in 2005 in nearby Wheat Ridge with help from the National Renewable Energy Laboratory.

The several new Ecofutures projects begun since Solar Harvest was completed have come in at 7 percent to 9 percent above standard building costs, Mr. Doub said. He said that he continued to tinker with Solar Harvest, which cost $987,000 to build. During the unusually cold winter of 2006-7, the solar heating system proved inadequate, so he installed backup electrical heating. He also installed air-conditioning after finding that the only way to do without it in the summer was to wake people on the south side of the house at 5:30 a.m. to close windows before the sun came up.

Last fall, the family replaced its gas appliances with electric ones, partly to make Solar Harvest more representative of homes in the future. He said he expected natural gas prices to continue to rise, driving consumers to electric appliances.