EnergyWise House: Elements of an Energy-Efficient House
Designing and building an energy-efficient home that conforms to the many considerations faced by home builders can be a challenge. However, any house style can be made to require relatively minimal amounts of energy to heat and cool and be comfortable and healthy.
It's easier now to get your architect and builder to use improved designs and construction methods. Even though there are many different design options available, they all have several things in common: a high R-value, tightly sealed thermal envelope; controlled ventilation; and lower than usual heating and cooling bills.
Insulated concrete forms are energy efficient and strong. In addition to reducing energy consumption, they create quiet interior spaces. Credit: renovateyourworld.com
Some designs are more expensive to build than others, but none of them need to be extremely expensive to construct. Recent technological improvements in building elements and construction techniques, and heating, ventilation, and cooling systems, allow most modern energy saving ideas to be seamlessly integrated into any type of house design without sacrificing comfort, health, or aesthetics. The following is a discussion of the major elements of energy-efficient home design and construction systems. The EREC has other, more specific information on these topics available.
The Thermal Envelope A "thermal envelope" is everything about the house that serves to shield the living space from the outdoors. It includes the wall and roof assemblies, insulation, windows, doors, finishes, weather-stripping, and air/vapor retarders. Specific items to consider in these areas are described below.
Wall and Roof Assemblies There are several alternatives to the conventional "stick" (wood stud) framed wall and roof construction now available and growing in popularity. They include:
• Optimum Value Engineering (OVE.) This is a method of using wood only where it does the most work, thus reducing costly wood use and saving space for insulation. However, workmanship must be of the highest order since there is very little room for construction errors.
• Structural Insulated Panels (SIP.) These are generally plywood or oriented strand board (OSB) sheets laminated to a core of foamboard. The foam may be 4 to 8 inches thick. Since the SIP acts as both the framing and the insulation, construction is much faster than OVE or it's older counterpart "stick-framing." The quality of construction is often superior too since there are fewer places for workers to make mistakes.
• Insulating Concrete Forms (ICF.) These often consist of two layers of extruded foamboard (one inside the house and one outside the house) that act as the form for a steel reinforced concrete center. This is the fastest and least likely technique to have construction mistakes. Such buildings are also very strong and easily exceed code requirements for tornado or hurricane prone areas.