Years ago, it was difficult to build a very energy efficient house because there was a lack of technology and materials -- such as extremely energy efficient insulation and triple-pane windows. The cost for solar panels was also high and subsidies were non-existent. Today this is not the case.

 We know how to build houses to substantially reduce the use of fossil fuel and energy costs. You might then ask: Why aren't all houses built to a much higher energy standard? There are several answers to this question.

 People aren't being forced to build more efficiently because the codes are not that stringent. Although they have improved over the years, most municipalities have a long way to go to be encouraging.

 Another reason given for not building to higher energy efficiency is the cost. Homeowners wrongfully assume that it will cost a great deal more to build a more energy efficient house. In 2010, Habitat for Humanity built a house in Vermont to Passive House standards, using a tiny bit of energy and at a minimal cost. Many other houses have also been built in this country and around the world that are moderately priced and extremely energy efficient.

 According to architect Phil Kaplan of Kaplan Thompson Architects, who designs many energy efficient houses in New England, "the up-cost for a very energy efficient house should be $0." He says, "If you increase window quality, increase insulation, reduce air infiltration, you reduce the cost of mechanical systems." When designing a house, Kaplan also designs the mechanical systems to make sure that he gets the right efficiencies in the completed house.

John Colucci, vice president of sales and marketing at Westchester Modular Homes, says the up-charge is minimal. He claims that a modular home may cost 3 to 5 percent more for a house that is 50 to 60 percent more efficient than the typical home. A house that is net-zero energy may cost up to 10 percent more. He points out that in the factory they are able to build a very tight house with advanced framing and extra insulation.

 Tessa Smith of the Artisans Group, a Passive House designer/builder says: "We see a zero upgrade in our custom energy efficient homes in which spending more on insulation gets recouped by less expensive but sophisticated mechanicals, and by buying better windows, which we would anyway in this type of house.

 "In our production-oriented houses (that are equally as efficient as our custom homes), we see an upgrade of between 5 to 10 percent (compared to a normal tract home) and a payback of around 6 years, depending on the project. The windows and mechanicals on these less-expensive houses are more energy efficient, of higher quality, and more expensive than the cheapest windows and mechanicals than you would normally find in a tract house."

 The Artisan Group currently has a Passive House under construction that will cost $135 a square foot.

 Nobody can say exactly what the return on the additional investment will be for all houses -- it varies with the products and systems used, location and the efficiency achieved. Everyone I've interviewed, with a very energy efficient house, however, agrees that their heating and cooling bills are substantially less than those of their neighbors with less-efficient houses.

Global warming is generally accepted today as a scientific fact. It is caused by the entrapment of gases resulting from the burning of fossil fuel. Forty percent of that fuel in this country comes from the heating and cooling of houses and other buildings. I believe the environmental and financial savings pose a strong case for building a very energy efficient or even zero-energy home.

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