THE EVOLUTION OF HEATING

Class [011]
Heating units, namely furnaces and heat pumps, structural component parts therefor; air distribution systems for furnaces comprised of forced air housing, blower and impeller, radiant or controlled infrared, heating elements, heat exchangers, and panel emitters; heating systems for residential and commercial buildings comprised of boilers, valves, pipes, manifolds, control panel switches, and electrical wire, all sold as a unit;