Lexington, KY - We want our next home - our downsized home - to be as "green" as we can get it. Our environmental objectives include resource conservation, natural lighting and ventilation, and indoor air quality. But the most important component of any green agenda is energy conservation.
We want to minimize our energy consumption for two reasons: global warming and personal greed. We respect science and scientists, so we're concerned about global warming. We may not be able to live a carbon-neutral life, but we can move in that direction. This means reducing energy consumption, particularly from fossil fuels. The personal greed thing is related to this: if we reduce consumption, we spend less money.
So here are four ways we will reduce energy consumption:
1) Downsizing, we're losing about 2,400 square feet with this move; 2) Replacing very leaky, single pane steel-framed windows with insulated, low e, wood windows; 3) Installing spray foam insulation; and 4) Installing a geothermal heating and cooling system.
I will focus here on the spray foam and geothermal. (Window replacement was discussed in the February 2011 issue of this magazine, and a future article will review other green building decisions).
We're using spray foam insulation because it is the best technology available. In fact, some data show that spray foam insulation can cut a home's heating and cooling costs by as much as 50 percent. The insulation fills every crack, virtually eliminating air infiltration, one of the primary causes of thermal inefficiency. It also acts as an air barrier, protecting the quality of the indoor air by preventing infiltration of allergens, molds and mildews. When we bought the house, there was a continuous line of mildew on the drywall just below the ridge line in the attic, where there was condensation caused by inadequate insulation. With spray foam insulation between the rafters, condensation and the related mold and mildew will not be a problem. Another noticeable advantage of this technology is the sound deadening quality - it is already much quieter in the treated spaces. Energy Star tax credits are available for spray foam insulation (see the provided "Useful Resources").
Geothermal heating and cooling is a relatively new technology that takes advantage of the fact that deep underground temperatures are consistently around 58 degrees. The ground acts as a heat sink or supply depending on the season. This is accomplished by circulating a liquid deep into the ground. (We drilled five holes about 170-190 feet deep in the front yard, into which pipes were inserted.) A heat pump is then used to transfer the energy as required. Typical air-to-air heat pumps are less efficient because outdoor air temperatures vary widely, and because thermal transfer using air is less effective than transfer using liquid. Geothermal is a renewable energy source that can save up to 70 percent over conventional systems. Other advantages include no outdoor units (no noise), a long life span, no exhaust, and at this time there is a 30 percent federal tax credit for such systems. The additional cost of this system over other technologies should be offset by the lower power bills within six years. After that, it's money in the bank, and another great bonus: peace of mind.