High Performance Homes
Thermal Envelope
A High-Performance-Home (HPH) is a purpose built structure comprised of various systems. The thermal envelope design theory has been around since the 1970s, but only recently, since the idea of a high performance building, has there been any real technology devoted to the idea. Only with the new materials and methods of construction has a safe, thermal envelope been possible.
The thermal envelope begins at the sill plate and encompasses the exterior wall assembly. Its purpose is to ensure a home's energy efficiency by a significant amount through the use of new materials and techniques. A successful envelope provides a thermal and air barrier between the inside and outside environments.
Exterior walls must be air sealed, protected from moisture, and insulated to do their job. If they are, they will increase comfort, reduce outside noise, and save on energy costs.
Air sealing will significantly reduce heating and cooling costs, create a healthier interior, and greatly improve building durability. Exterior wall assemblies are susceptible to, and must be protected from moisture incursion. Their design should keep moisture out and at the same time allow moisture that does get in to get out. To do this there has to be a complete, lapped and drained moisture barrier beneath the exterior surface.
Well placed, properly selected insulation is, and will continue to be one of the most cost effective ways to control energy consumption and make for a year around comfortable living environment.
Windows and doors, poorly selected and improperly installed are the largest holes in the thermal envelope. The average American home looses 30% of its heat and air conditioning through its windows.
