The thermal envelope is the barrier used to protect your interior environment from heat transfer from inside to outside. It may be portions of the exterior envelope and portions of interior elements. The effectiveness of this barrier is dependent on insulation levels, air tightness, and thermal properties of windows and doors.
Improvements in the thermal envelope can reduce heating and cooling requirements dramatically over code compliant construction practices at little to no added costs. It is the first line of defense in a home or office for comfort, low energy bills, and healthy indoor air quality.