Split system heating and cooling systems or "central air-conditioning systems" have equipment installed both inside and outside the home. In a split system, the condenser or heat pump is installed outside the home, and a furnace or air handler is installed inside the home. The indoor and outdoor components of a split-system are connected by refrigeration pipes and a low-voltage electrical wire.

A central air-conditioning system uses ducts to distribute cooled air throughout the house. In a “split system” (the most common design) refrigerant circulates between an indoor coil and a matching [meaning from the same brand] outdoor condenser with compressor. The refrigerant cools the air, dehumidifying it in the process; a blower circulates air through ducts throughout the house. A thermostat maintains the temperature at the setting you select. A common variation of a central air conditioning system is the “heat pump”, a type of system that functions as a heater as well as an air conditioner.

Another variation of a split air conditioning system is a "gas heat", which offers you electric air conditioning and gas heating. In warm weather, it's an all-electric high-efficiency air conditioner. In cold weather, it provides warmth from natural gas or propane, giving you the best of both energy worlds.

Lastly, is the "dual fuel" system, which is a combination of "gas heat" and "heat pump". This option offers the most efficient for cold weather environments that require heating year-round. In the milder cold months, the heat pump is activated for heat and in the more extreme cold months, the gas furnace is used as the primary source of heat.