Energy-Efficient Home Design 101
Thermal envelope energy-efficient home design tips:
In an energy-efficient home design, great care must be taken to ensure that the thermal envelope is meticulously planned and working as it should to shield the inside of the home from the outside world. The term thermal envelope includes roofs, foundations, insides of walls, insulation, windows, doors, specialized finishes or treatments, air/vapor retardants, and all other barricades against the outside elements.
Air-Sealing: Within the thermal envelope, all air leaks need to be sealed to ensure the proper indoor environment. Areas of concern often include odd-shaped areas around appliance outdoor access ducts and around any pre-fabricated window, skylight, or door installations.
Air/Vapor Retardants: The most common residential water or vapor control systems for the thermal envelope area are the Simple CS system or Airtight Drywall systems. Both types of systems require an airtight installation of drywall and sheet materials, so seal everything well the first time.
Foundations and Slabs: Basement walls, floors, and crawl spaces all need to be insulated to the same R value, or higher, than the living spaces of the home.
Insulation: Forget about what the building codes say about insulation. In an energy-efficient home everything is done with higher R values. A rule-of-thumb would be to aim for R-30+ in the walls, and R-70+ on ceilings, basements, and foundations.
Windows: Unless you have experience in passive solar techniques, it is best to keep the window area to less than 10% of floor space. Even with upper-quality windows, an unwanted heat increase or heat reduction will happen inside of the thermal envelope through the overuse of windows.
Within an energy-efficient home design care is also taken to control ventilation within the tightly sealed thermal envelop, and to initiate proper safety and comfort factors having to do with the heating and cooling systems. In some situations, landscaping also plays a part in this style of home designs where water runoff is controlled through sub-system drainage and the use of specialized grass holding pavers instead of traditional plantings.
