For the purposes of sections 16a-40a to 16a-40c , inclusive, and this section:
(a) “Commissioner” means the Commissioner of Housing;
(b) “Alternative energy device” means a wood-burning stove for space heating and any system or mechanism which uses wood, solar radiation, wind, water or geothermal resources as a source for space heating, water heating, cooling or generation of electrical energy. Such alternative energy device may be a new source or system, a replacement of an existing source or system or a supplement to an existing source or system; and
(c) “Residential structure” means any building in which at least two-thirds of the usable square footage is used for dwelling purposes.