Achieving a truly energy-efficient home may be easier in concept than in execution, though the components of energy-smart construction should be well-known by now.
The easiest energy improvements can be realized in an existing home by the simple measures of caulking around windows and doors and increasing attic insulation to R-50. Current tax credits make it more cost-effective to upgrade insulation.
Achieving the goal of energy efficient new construction sometimes requires perseverence on the part of a homeowner. Constant vigilance and communication with architects and contractors are necessary to insure the use of preferred best building practices and materials. For a modest 300-square-foot main level home addition, I was surprised by the architect's inclusion of an elevated ceiling/scissor-truss roof. Ceiling elevation seemed disproportionate to the space, and my desire to ensure R-50 ceiling insulation prompted the decision to partially lower the ceiling with collar ties.
My primary goal for an addition was energy efficient construction using passive solar design. Special solar gain windows were oriented southward, shaded in the summer by a 2-foot roof overhang. Building materials were chosen to create an efficient thermal barrier and to preserve the integrity of the building envelope to keep heat out in the summer and to retain it in the winter.
Some features of the addition:
• Pre-cut SIPS Panels (Structural Insulated Panels) by Rocky Mountain ICS (Insulated Component Structures) were pre-fabricated at the factory, formed with 2 outer pieces of OSB (oriented strand board) with a closed-cell polyurethane foam center core. Wall thickness and insulation value can vary up to 8.25 inches thick (R-54). I chose 4.5 inch wall panels (R-28), suitable for the Colorado plains area.
• Well-sealed (caulked and foamed) joints help ensure the thermal efficiency of the building envelope.
• Special roof sheathing backed by perforated (for ventilation) reflective foil lining can block more than 97% of the sun's radiant energy, thus minimizing radiant heat penetration into the attic and living spaces. Four passive roof vents ensure proper attic ventilation.
• Some Roof Shingles with the Energy Star label also reflect heat away from the roof, and are eligible for a 30 percent rebate, or up to a $1,500 federal rebate on the cost of installation. GAF and Owens Corning both make Energy Star-rated shingles.
• R50 insulation extended throughout the entire attic helps moderate the temperature throughout the house.
Attention to detail in my modest addition paid off, and results have exceeded my expectations. While neighbors on either side ran air conditioners almost continuously through the summer, my home did not even require a fan. It was only necessary to crack open windows at opposite ends of the house at night to achieve good cross-ventilation to cool the space.
As slow as we have been to come to it, we know how to build energy-efficient homes. The question is why more new or retrofitted homes are not incorporating more energy-wise materials and practices.
Further energy savings are possible with Solar Photovoltaic Panels to supply a home's electricity, or a Solar Thermal hot water system, making it possible to achieve, or at least approach, a net zero energy home.
Current tax credits provide incentives to solarize and upgrade energy efficiency. Tax Credits to 30% of costs of materials for insulation, heating and cooling systems, etc. - up to $1500 - are available through Dec. 31, 2010. Tax Credits for such energy-saving systems as solar and geothermal extend through 2016.