"Building envelope" means the elements of a building, such as walls, windows, foundations, basement slabs, ceilings, roofs, and insulation materials, that separate conditioned space from unconditioned space, semi-heated space, or the exterior of the building, through which thermal energy may be transferred to or from the exterior, unconditioned space, or conditioned space.
N.H. Admin. Code § Env-A 4702.06
#9481, eff 5-23-09; ss by #10469, eff 1-1-14