Affordable Energy Efficient Homes Have Arrived

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Why Aren’t Corporate Builders Building Them?

By Alan Hoffman

On a recent call to Centex Homes in south Santa Fe I asked, “How energy-efficient are your homes?” and I was told “very energy-efficient, all our homes are HERS 70.” I love it when salesmen throw around numbers and a bunch of letters; it sounds like they know what they are talking about, but do they? Interestingly enough, in this case they did. A HERS rating is a calculation that considers insulation, building tightness, and the efficiency of the appliances and lighting, among other energy-efficient considerations. There has been much made about the city of Santa Fe’s energy-efficient building requirements and the fear by some builders that these requirements would price Santa Fe out of the new home market. But, lo and behold, Centex Homes, a large-scale merchant builder, when required, can deliver at tract home prices, fully verified energy savings of at least 30% compared to a modern code-built home. Considering that modern codes are far more efficient than older codes, a HERS 70, the Santa Fe city requirement, isn’t that bad.

But how good is a HERS 70? Over the years I have represented experienced green builders, including Artistic Homes and Renaissance Builders, and found that advanced framing techniques use 20% less lumber, 20% less labor, have 20% less heat loss, and with properly installed insulation and efficient equipment can get around a HERS 53 or a savings of 47% compared to a home built to the existing code, known as the International Energy Conservation Code. With the cost of gas and electricity fluctuating wildly over the last five years and the cost of upgrading a home from code to HERS 55 at between 2% and 3%, why doesn’t everyone build using the newest techniques to attain those savings? I can only guess that these corporate builders have decided they care about the minimal cost advantage, and their customers don’t know how substantial these savings can be as the cost of energy begins to rise again.

And when you move from tract houses to custom homes, the savings get greater and the cost increase becomes even less significant. The modern custom home built by experienced green builder Renaissance Homes attains a HERS rating of around 52 from efficiency and conservation alone, and with the addition of photoelectric panels, can get to HERS ratings of around 20, meaning a savings of 80% in gas and electricity use. Add to this the Renewable Energy Credit paid by PNM, and these homes can approach or exceed the Net-Zero Energy cost. (PNM is trying to get rid of the RE Credit at the Public Regulation Commission). In a home built in Oshara Village and upgraded with solar-thermal and solar-electric packages, we estimate that the house approaches a HERS 20, but the couple living in the home are aware of their energy use and conserve energy whenever possible. A recent analysis of their utility bills found that they are doing better than zero, and net around $72 a year above their energy costs.

When you look at your monthly expenses, there is only one that is fixed for up to 30 years; that is your mortgage. As the baby boomers are beginning to retire, there is increased concern about out-of-control energy costs. The idea of building future energy costs into today’s mortgage is starting to make more sense. And it is possible to oversize a solar-electric array on a house, buy one of the new plug-in cars and build future transportation costs into today’s mortgage as well.

Natural Homes, Renaissance Builders and Trend Magazine are sponsoring a reception on March 17 at their newest solar home on Coyote Ridge Road in Santa Fe. Two Sundays of presentations on sustainable building will follow.


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