Do You Need to Press the AC Button When Using the Car Heater in Winter?

[VanGabriella]

Normally, you do not need to press the AC button when using the car heater in winter. AC stands for Air-conditioning, which means air conditioning adjustment. In summer, pressing the AC button turns on the compressor, which blows cold air through air compression. However, in winter, the car needs warm air to continuously raise the interior temperature to a level comfortable for the human body. The warm air is provided by the engine, which generates a significant amount of heat while running. At this time, you only need to channel this heat into the air conditioning system, and warm air will blow out from the vents. Therefore, there is no need to press the AC button. Using the heater in winter does not increase fuel consumption. This is because the warm air blown by the heater comes from the heat generated by the engine. Even if you don't use the heater, this heat would otherwise be expelled outside the car. In a way, using the heater in winter actually reduces the burden on other car components, such as the engine's cooling system. However, it is important to note that you should not run the heater for extended periods in winter. While the engine generates heat, it also produces harmful gases that can enter the car through the air conditioning system. Therefore, when using the heater in winter, it's advisable to open the windows periodically to ventilate the car and minimize potential harm to the body.

[VonNova]

As a seasoned driver with years of experience, I can tell you that you basically don't need to turn on the AC button when using the heater in winter. This is because the warm air comes from the waste heat of the engine. Turning on the AC activates the air conditioning compressor for cooling and dehumidification, which not only wastes fuel but may also make the air dry and uncomfortable. When I drive in cold weather, I simply turn the temperature knob to the warmest position and keep the AC off all the time. If there's fogging on the windows or high humidity on rainy days, I temporarily turn on the AC for quick and hassle-free dehumidification. Operating this way in the long run can save a lot on fuel costs and protect the car's systems. Even in the icy and snowy conditions of the north, the heater works just fine without the AC. I recommend that new drivers try this method more often to develop the habit—it's simple, efficient, and practical. After driving for a long time, you'll realize this issue isn't complicated at all, and not using the AC 90% of the time is sufficient.

[AlexRose]

As someone with some basic car knowledge, I'd say you generally don't need to press the AC button when using the heater in winter. The warmth comes from the engine coolant, while the AC compressor is specifically for cooling—turning it on only dehumidifies without adding heat, and it consumes extra energy. However, if your windshield fogs up, turning on the AC can quickly clear the fog for better visibility. In daily use, I increase the fan temperature and turn off the AC for a warm and economical ride. In humid areas, using the AC occasionally for dehumidification works well, but avoid keeping it on constantly to save fuel and protect AC components. From my own tests, normal heating without AC keeps the car just as warm while improving fuel efficiency. Adjusting based on weather conditions is the smartest approach—it's hassle-free and protects your car.

[DeNathan]

As a beginner driver, I also wondered if I should turn on the AC when using the heater in winter. After learning more, I found that in most cases, it's unnecessary. The heater relies on the engine's heat, and turning on the AC activates the compressor, which adds unnecessary trouble and consumes more fuel. However, when the windshield fogs up, using the AC for dehumidification is quite effective. My routine is: start the car, wait for the engine to warm up, then turn on the fan and turn off the AC, setting the temperature to a comfortable level; if fogging occurs, pressing the AC button a few times solves the problem. This way, it's warm, convenient, and safe.