Designing and building a zero energy home has many moving parts, starting at the initial design phases and well into the ongoing performance. All parties involved have to align as a collaborative force to manage the energy use. Here, this project exemplifies the importance of working together.

Zero energy custom homes are done best when they are approached as a collaboration between client, designer, and builder. And the best collaborations come when each of these three actors fully engage their own role without spilling too far into other areas. The result is a building that meets the client’s needs and functions effectively at a reasonable cost.

The collaboration between builder Terry Davenport and homeowners Sidney and Belenda Mehlschmidt exemplifies the power of this collaboration. Sidney Mehlschmidt is a retired commercial pilot who has designed and commissioned two previous custom homes, giving him a good idea of his family’s needs and the skills required to translate them into physical form.

“I wanted to satisfy three design requirements,” says Mehlschmidt. “Universal design for aging in place, a farmhouse look that fits with the rural Montana culture, and a home that was highly-energy efficient.”

The Mehlschmidt home was completed in 2013 and covers 1,936 square feet with one bedroom on the first floor and a large, second-floor art studio/guest room including an adjacent bathroom. Their 7.5 kW solar electric system generates more electricity than he and his wife use on an annual basis. While their neighbor spends about $185 per month for utilities, they spend only $4.10 per month for the electric utility billing fee. The utility’s net metering contract allows them to accumulate credits for excess solar power generated in summer and then use those credits the following winter.

In addition to solar electricity, this home uses four solar thermal collectors to accomplish two tasks: provide domestic hot water and drive the in-floor, hydronic space heating system. The solar thermal system is backed up with a standard 50-gallon electric water heater wired so that both electric heating elements in the tank operate together.

Their builder, Terry Davenport of Natural Housebuilders, has been designing and building energy-efficient homes in Montana for around forty years (check). “It’s a form of performance art,” says Davenport. “You can’t see many of the features, but you can feel them.”

Integrated Design
Davenport praises the integrated design/build model because the functions are interdependent. In the more common situation where an architect or designer transfers the project to an independent builder, frequent communication and collaborative problem solving are absolutely necessary.

According to Davenport, zero energy homes can be cost competitive with conventional homes. First, small size reduces all costs, from permits to framing and from drywall to floor covering. Computer energy modeling can be used to optimize energy features. A zero energy house may often be more expensive to build, but it will be less expensive to live in. “I don’t charge as much as some other builders because I have my own crew to do some work that other builders would sub out,” he says. “It takes longer to build, but there is less overhead.”

By combining the design/build functions, Davenport streamlines the construction process. As one might expect, years of experience allow him to avoid common pitfalls of home building. Perhaps less obvious, but equally important, is his ability to quickly adopt new materials, techniques, and equipment. The construction industry is often criticized as being slow to change when, in reality, new ideas are appearing constantly. These cutting-edge techniques are almost always adopted first in custom homes driven by forward-thinking designers, builders, and clients.

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