What type of system do you have?
Air Conditioning units and heat pumps look alike, however, A/C units provide cooling only, and rely on heat strips, or gas for their source of heat.
Heat Pumps provide both cooling and heating through the use of a change over valve. Heat pumps systems have heat strips as a backup source of heat, and to assist the system during the defrost cycle.
Package systems are both the condensing system and blower system in one unit. Package systems can be either air conditioning or heat pump systems.
Split Systems are systems that have an outside condenser and an indoor air handler or blower.
Gas is used for heat in some systems. The gas burners are part of the furnace / air handler.
Filtration refers to the type of filters or air cleaners you may use to clean the air you breathe and protect your system from bacteria, dust, and mold.
Ventilation refers to air removed or added to a room. Bathroom exhaust fans, stove hoods, fresh air dampers are just a few of the basic styles.
Fresh Air Exchangers are designed to exchange indoor and outdoor air while retaining the conditioned temperature. Exchangers provide fresh air while saving energy.