Should the AC be turned on for heating?

[SerenityLynn]

Heating does not require turning on the AC. The AC button in a car controls the compressor's switch, while heating primarily utilizes the internal heat circulation of the car to maintain the cabin temperature. During this process, the compressor does not operate, and you only need to adjust the airflow volume. Turning on the AC button may lead to unnecessary fuel consumption. Winter heating usage tips: Do not use heating immediately after a cold start: When the car is started cold, the temperature inside the radiator is relatively low. Turning on the heating at this time will not only fail to raise the cabin temperature but also increase the engine's load, slowing down the engine's temperature rise and affecting normal operation. It will also increase fuel consumption. It is recommended to wait 8 to 15 minutes after starting the car before turning on the heating.

[Grant]

Generally, you don't need to turn on the AC button when using the heater in winter. After driving for over ten years, I've found that the warm air is heated by the engine's heat. Turning on the AC will only make the compressor work unnecessarily, wasting fuel. For example, on very cold days, simply adjust the temperature to the heat setting. Only if the windows fog up badly should you temporarily turn on the AC for dehumidification. Remember to check if the blower is working properly to prevent the air inside from becoming too dry, which can affect comfort. Overall, don't complicate simple things—save fuel and hassle.

[EmiliaFitz]

When using the heater in the car, whether to turn on the AC depends on the situation. I know from my usual vehicle operation that the heating system utilizes the heat from the engine coolant, and the compressor doesn't work. However, on rainy or humid days when the windows are prone to fogging up, turning on the AC can quickly dehumidify and prevent blurred vision. At other times, turning on the AC only increases fuel consumption and is unnecessary. During vehicle maintenance, pay attention to regularly replacing the cabin air filter to make the heating system more efficient and healthier.

[HaileyDella]

You don't necessarily need to turn on the AC for warm air. As a novice driver, I also mistakenly thought they had to be used together. Later, I learned that the warm air works by utilizing the engine's residual heat, and turning on the AC only assists in dehumidification or cooling. If the windshield fogs up, turning on the AC can help alleviate it, but keeping it off most of the time can save a lot on fuel costs. Don’t overlook the position of the blower switch when using the car—properly adjusting the airflow and temperature will make driving safer and more comfortable.

[DiSpencer]

Turning on the AC while using the heater increases fuel consumption and emissions. I personally prioritize environmental protection and energy efficiency, knowing that the AC compressor consumes more fuel, while the heating system operates independently and efficiently. I only turn on the AC for quick dehumidification when the windows are severely fogged up, otherwise I keep it off. During vehicle maintenance, I pay attention to whether the engine temperature is normal to ensure sufficient heat supply for the heater.

[OmarLee]

Many people think that turning on the heater requires the AC, but that's not the case. I've tested it several times, and the heater relies entirely on engine heat. The AC button is mainly used for dehumidification or cooling. Unless it's during the humid season or in cold, damp conditions when the windows fog up, there's no need to turn on the AC. Otherwise, keeping it off can avoid wasting resources and affecting the compressor's lifespan. Trying the manual defogging function during vehicle operation is also quite practical.