Nine out of ten homes in the U.S. are under-insulated. By sealing air leaks and adding insulation during the construction phase of a home, builders can save their homebuyers up to 10% on their annual energy bills. 

Insulation

It’s important to insulate the walls, floors, and ceilings with the type and thickness of insulating material that fits the specific needs of each surface, and to design wall, floor, and ceiling assemblies to accommodate those materials. Building materials all resist the flow of heat to some degree, the thermal resistance property of which is expressed as the R-value. Optimizing insulation thickness and R-value is a key design task for all high-performance homes. In North America, wall insulation values can range from R-19 in mild climates to R-40 in cold climates, to as much as R-60 in very cold locations. 

Air Sealing and Ventilation

Air sealing the building envelope is one of the most critical features of an energy efficient home. To prevent air leakage, it’s best to seal the building envelope during construction prior to the installation of drywall. Once covered, many air leakage paths will be more difficult and costly to access and properly seal. In new homes that are tightly sealed, builders need to ensure there is adequate fresh air for ventilation. In many ENERGY STAR qualified homes, an active ventilation system (such as an energy recovery ventilator) is installed along with air sealing to ensure that fresh air is provided. 

Building Envelope Resources