Your thermostat has two fan settings: on and auto—but which one should you use? Our San Antonio HVAC technicians often get asked this question, so here’s a quick guide to help you decide which setting might work best for you.
What’s the Difference?
- On: The fan runs continuously, even when the A/C or heater isn’t actively cooling or heating.
- Auto: The fan only runs when the system is actively heating or cooling and turns off a minute or so after the desired temperature is reached.
Does It Matter?
Both settings have pros and cons, depending on your home and comfort preferences.
Using the “On” Setting
- Helps circulate air, especially in homes with hot spots or multi-level layouts with a single HVAC unit.
- Can help distribute warm air trapped near high ceilings during winter.
- Can reduce strain on the motor from frequently starting and stopping, the typical cause of motor wear and tear, since the motor runs continuously on this setting.
- May help improve air filtration by keeping air moving through the HVAC filter continuously, which can be beneficial for those with allergies or respiratory issues. Remember that it’s important to keep up with filter changes, since continuous circulation can cause dust and debris to accumulate more quickly.
Using the “Auto” Setting
- More energy-efficient, as the fan only runs when needed, reducing electricity costs.
- May feel more comfortable during the heating cycle since the fan will stop blowing air, which otherwise may feel cooler, into the room when the heater is off.
- Less humidity is introduced in the home during the cooling cycle. Since the fan stops running when the outdoor unit stops running on this setting, the fan won’t dry out the wet indoor coil or blow the moisture collected back into the house.
- May require less frequent air filter replacement since the fan isn’t running 24/7, leading to slower dust buildup. But, because there’s less air circulation when the system is off, you’ll still want to stay on top of regular filter changes.
What’s the Best Setting?
There’s no one-size-fits-all answer. Every home—and homeowner—is different. If you struggle with hot and cold spots in your home, the On setting may help. If humidity tends to be an issue, Auto is usually the better choice. The best approach is to experiment with both settings to see what works best for your comfort and energy use. You may quickly notice that you prefer one setting over the other.
Need expert advice on optimizing your HVAC system and making it more efficient? Contact our trusted HVAC professionals at North East Air Conditioning, Heating & Cooling today!
