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Energy-Efficient Home to Save 85 Percent Off Utility Bills

A Tennessee resident has almost single-handedly built an extremely energy-efficient home that will do more than just save energy. Eric Enos estimates that his home will cut monthly utility bills by about 85 percent when compared to the residential energy costs of a similarly sized home.

Enos built his home on a knoll on the north side of Black Oak Ridge overlooking Oliver Springs, Tennessee and covered three sides of it with mounds of dirt. Enos estimates that other homes about the same size would have monthly power bills of $400 or more, but that his “worst case scenario” power bill would be about $60. And that’s with 16-foot-tall ceilings in the kitchen and living room.

Enos, who has been building his home almost entirely by himself after work and on weekends while he and his family reside in nearby Solway, says that his home’s energy efficiency is “all-inclusive” and that the structure is almost completely maintenance free.

The home is constructed with foot-thick walls of insulated steel-reinforced concrete, which builds up a thermal mass. As Enos explains, insulated concrete helps inside temperatures stay more consistent while blocking temperature fluctuations from outside, dramatically decreasing the amount of work needed from furnaces and air conditioners.

Since steel and concrete are the two most stable building materials, Enos says the combination of materials and the earth-sheltered nature of his construction provide the home with exceptional insulation while making it earthquake-resistant and nearly tornado-proof. Because there’s no wood, expansion and contraction issues that affect wood homes aren’t an issue and termites and fires can essentially be ruled out as concerns, according to Enos.

Reliance on Power Companies Cut with Geothermal Heating and Cooling

Perhaps the most interesting feature of Enos’ home is his use of geothermal heating and cooling to cut his reliance on power companies. Buried inside one of the mounds, between five and 14 feet deep, are 1,700 feet of geothermal lines, which enter the home and run throughout the concrete floors.

The earth keeps the water in those lines a cool 58 degrees, the average annual temperature in Oliver Springs. In the summer, a geothermal pump in the attic circulates the cool water through the lines in the home’s concrete floors, keeping the home cool. In the winter, water in the lines under the floors is circulated through a tankless water heater in the garage, which heats the water and sends it back under the floors to heat the concrete, keeping the home warm.

The home’s construction also includes a metal roof with a six-inch layer of insulating foam designed to prevent leakage and to deflect much of the sun’s heat away from the attic and living space below. Enos even uses special low-energy LEDs (light-emitting diodes) for interior lighting that are supposed to last 35,000 hours.

Enos says the 2,400-square-foot home with 1,200-square-foot, three-car garage cost him about twice as much per square foot as a normal new home. Although some people may say that’s overkill for an energy-efficient home, Enos says it’s just a case of “being a perfectionist.”

However, Enos does caution that designing a home like his is really only for people who plan on living in it long enough to recoup the added cost. "Building a house this way is not an intelligent move if a person is looking to move within the next five to 10 years," he said.


Homeowner Puts in a Year of Work on Model of Frugality, Efficiency,” Knoxville News Sentinel, July 5, 2011.

7/22/2011 8:14:00 AM
in Energy Savings Energy Education