(2) The rating system shall provide a single numerical value or other simple concise means to measure the energy efficiency of any single family residence, taking into account factors including, but not limited to, the heat loss characteristics of ceilings, walls, floors, windows, doors and heating ducts.
(3) Upon adoption of the rating system under subsections (1) and (2) of this section, the department shall publicize the availability of the system, and encourage its voluntary use in real estate transactions.
(4) As used in subsections (1) to (3) of this section, "single family residence" means a structure designed as a residence for one family and sharing no common wall with another residence of any type. [1977 c.413 §§1,2,3; 1993 c.744 §113; 2003 c.675 §44; 2009 c.567 §§9,22]