Package Air Conditioner + Gas Furnace—A package system is located on your roof and uses gas for heat and electricity for cooling.
Package Heat Pump—A package heat pump system is located on your roof and uses only electricity for heating and cooling your home.
Split Air Conditioner + Gas Furnace—With a split gas system, the air conditioner unit is located outside on the ground, while the gas furnace / air handler is located elsewhere (often in the garage or the attic).
Split Electric Heat Pump—With a split heat pump system, the air conditioner unit is located outside on the ground, while an electric air handler is located elsewhere (often in the garage or the attic). Split heat pump systems rely solely on electricity.
If you have a gas bill that is noticeably higher in the winter time, your current heating system probably uses gas.
Annual Fuel Utilization Efficiency (AFUE)—Measures how efficiently a furnace can convert fuel to heat. Furnaces with an AFUE rating of 80–83% are considered moderately efficient while furnaces with an AFUE rating of 90% or above are considered highly efficient. With a higher AFUE rating, less fuel will be required to heat your home.