Is it useful to turn on AC when using car heater?

[VonJordan]

Heating only utilizes the internal heat circulation of the car and does not require activating the compressor. Therefore, to use the heater, you only need to adjust the air conditioning button and should never touch the AC switch. The function of the AC button: The AC button in a car controls the switch of the air conditioning compressor. The working principle of the air conditioning compressor is to compress and drive the refrigerant in the air conditioning refrigerant circuit, so generally, there is no need to turn on the AC button when using the heater. Therefore, the idea that many car owners have about needing to turn on the AC button when using the heater is incorrect. The impact of using the heater on fuel consumption: The principles of heating and cooling are actually quite different. The heater relies on the heat dissipation from the engine. There is a small fan in the engine compartment that blows the heat collected by the cooling system into the car. If the heater is not turned on, this heat will be discharged outside the car, so using the heater in winter does not consume fuel.