In this subtitle, the following terms have the meanings indicated. Terms Defined. “Apartment house” means a building containing more than two dwelling units all of which are rented primarily for a non-transient use, with rentals paid at intervals of one week or longer. Apartment house includes residential condominiums and cooperatives, whether rented or owner occupied. “Approximate energy use” means the gas or electricity use within a dwelling unit as determined by an energy allocation system. “Commission” means the Public Service Commission of Maryland. “Dwelling unit” means a room or rooms suitable for occupancy as a residence containing kitchen and bathroom facilities. “Energy allocation equipment” means a measuring device or other equipment used to determine approximate energy use by a means other than the actual measurement of consumption of gas or electricity. “Energy allocation system” means a method of determining the approximate energy use consumed within a dwelling unit with the use of a measuring device. “Estimated energy costs” means the cost of gas or electricity which is reasonably expected to be allocated to an occupant under an energy allocation system. “Measurement unit” means the measure of the characteristic recorded by a measuring device. “Measuring device” means a device which measures furnace operating or running time, baseboard pipe temperature or other characteristics used to determine approximate energy use. “Occupant” means the resident of a dwelling unit in an apartment house. “Owner” means a person or entity holding legal title to an apartment house or the board of directors or similar body of a residential condominium or cooperative. Owner includes an authorized agent of an owner. “Utility” means the public service company which supplies gas or electric service to the apartment house. “Vendor” means the entity which provides the energy allocation equipment and billing services to an owner.