When it came to building their dream home, David Pill and Hillary Maharam faced a couple of unique challenges.

For one, the pair of Washington University architecture graduates proved to be their own toughest clients.

"Designing a house for yourself as an architect is one of the most challenging design projects you can do," said Pill (MArch87), who founded Pill-Maharam Architects with Maharam (BArch86) in 1991. "At least for me it was. Because I had very specific ideas, and I wanted everything to be just the right way."

More importantly, Pill and Maharam were committed to building a house that had as little environmental impact as possible. The result of their efforts is a 2,700-square-foot, zero-carbon-emitting home in Charlotte, VT.

In early March, the Northeast Sustainable Energy Association (NESEA) presented Pill and Maharam with the Zero Net Energy Building Award, which came with a $10,000 cash prize. Their home has earned other honors, including the AIA Vermont honor award for sustainability and design in 2008 and the Efficiency Vermont's Best of the Best award in 2007. It is also the only house in all of Vermont with a LEED platinum certification.

Issues of sustainable design were important to Pill and Maharam well before they began drawing up plans for their own house. Maharam currently works in the area of landscape design. Pill said he has been going to sustainable building conferences for about 18 years and has done a lot of research on the techniques, methods, and materials used to build energy-efficient buildings. The first payoff for that research came in 1999, when Pill-Maharam built its first house based wholly on those principles of sustainability.

That experience came in handy when Pill and Maharam, who had been living in Boston, decided they wanted to move to a more rural locale about five years ago. "It was nice to have that all culminate in the building of our house," Pill said.

The couple's initial plan was to retrofit an existing house to make it more green, but they had trouble finding a suitable property with an existing building. At the same time, they were determined not to build on pristine land.

Their search for the perfect spot ended in Charlotte, VT, where they found a parcel of land that housed a riding arena with a large steel frame. Pill said a neighbor ended up moving the frame and is in the process of rebuilding it.

Not only did the site give them great access to the sun, but it also provided a great wind source. In fact, Pill said that a 10-kilowatt wind turbine takes care of all the home’s energy needs.

The design process proved to be the most challenging part of the project, as Pill and Maharam focused on getting every load down to ensure the home was as efficient as possible. They began working with contractor Jim Huntington and energy consultant Andrew Shapiro early in the process, to ensure everyone was on the same page. Construction of the house took a little under a year.

One of the couple's goals from the start was to not use any fossil fuels—even their cooking is done with electricity. "We didn't like the idea of the energy used to transport fossil fuels, and we didn't like the idea of the energy used to expend them," Pill said. "If you are not using fossil fuels, your options are limited. That set up the criteria we needed to heat the house with the electricity generated on site. A ground source heat pump was the most efficient solution for this purpose."

The most efficient solution, in this case, was a ground source heat pump, which is used for heat and domestic water. In addition, Pill and Maharam designed a super-insulated passive solar house that is long along the east-west axis, presenting as much surface area to the sun as possible. Not only does that allow the concrete floor, which acts as a thermal mass, to absorb as much heat as possible, but the layout allows natural light to fill the house, eliminating the need for artificial lighting.

Building an environmentally friendly home didn't mean Pill and Maharam had to throw their own design tastes out the window. The couple fused their modern aesthetic with the agricultural context of the area. The exterior of the home evokes the look of a barn with a contemporary twist, while the interior has lots of open, clean lines, steel beams and columns. 

In addition to helping the environment, Pill and Maharam—who have two kids, also benefit from the savings the house provides their wallet.

"We don't have any bills," Pill said. "No electric, no heating, nothing. Actually, we gave power back to the grid last year."

Already, Pill said the house has generated a lot of interest from his firm's clients. Although some of the specific design elements he and Maharam included increased the cost of building a little (he estimated the home cost around $196 per square foot), he said that the envelope for the building is fairly simple, meaning the house could easily be replicated for less money.

Moreover, the fact a zero-net-energy home could be built in a colder climate proves that geography doesn’t have to restrict the ability to build sustainable homes.

"If we can do it up here, this is definitely possible in so many places in the country," Pill said. "That gives me great optimism about what we can do right now, and what we will be able to do in the future."