Should You Turn on the AC When Using the Car Heater in Winter?
4 Answers
In winter, you do not need to turn on the AC when using the car heater. The heater relies on the heat generated by the engine. There is a small fan in the engine compartment that blows the heat collected by the cooling system into the car. If you don't use the heater, this heat will be expelled outside the car. Simply turning on the heater without pressing the AC button is just utilizing waste heat and will not increase fuel consumption. During very cold winters, some car owners keep the heater on for extended periods. Since the heat comes from the engine, prolonged use can produce toxic gases like carbon monoxide, which can be dangerous for people inside the car. If the driver feels that the air inside the car seems unusual, they should immediately open the windows and doors to ventilate and expel the toxic gases.
As an experienced everyday driver, I find it completely unnecessary to turn on the air conditioning for heating in winter, but the AC can indeed be very helpful. For example, during damp and cold weather when the windows fog up, activating the AC system can quickly dehumidify the air, ensuring clear visibility and enhancing driving safety. My usual practice is to start the car, turn on the heater to a comfortable temperature with medium fan speed, and if I notice fogging, I press the AC button to let it work for a few minutes until the fog clears, then turn it off. This approach avoids unnecessary fuel consumption and extends the compressor's lifespan. On my daily commute, this habit has made driving much more worry-free while keeping the cabin comfortable. Remember, the AC isn't for heating; using it only when dehumidification is needed is the most cost-effective approach.
From a maintenance perspective, I recommend using the air conditioning less when driving in winter to reduce unnecessary component wear. The warm air comes directly from engine waste heat, so there's no need to use the AC for heating; turning it on forces the compressor to work continuously, increasing fuel consumption and potential failure risks. Personally, I prefer using only the heater on dry, sunny days, setting the temperature around 22°C with automatic fan speed. I only briefly turn on the AC for dehumidification on humid mornings or during rain/snow when the windows fog up. This approach not only protects the vehicle's systems but also saves fuel and money. In the long run, following this principle can make your car's AC components more durable and reduce maintenance headaches.
As an average car owner, I feel whether to turn on the AC when using the heater in winter depends entirely on personal needs and road conditions. If you're driving in humid areas, like when there's often morning fog on your commute, turning on the AC can quickly solve visibility issues and make driving safer. But in dry weather, just the heater provides sufficient comfort. My approach is simple observation: after turning on the heater, if the fog doesn't clear within seconds, I press the AC button to assist with dehumidification - it usually works within 10 seconds. Setting the temperature between 20-24°C is ideal; any higher becomes uncomfortably stuffy. Remember the AC isn't mandatory - flexible usage best balances comfort and efficiency.
