What Does Aux Heat Mean on My Thermostat?

Have you ever seen the words “aux heat” on your digital thermostat and wondered what exactly it means? Well, aux heat might just save the day. Sometimes mistaken for emergency heat, aux heat is a heat pump thermostat setting.

Read on to learn how “aux heat” differs from “emergency heat” and more about this oft seen, but lesser known heat pump feature.

“Aux” is short for auxiliary heat. If a heat pump is having a difficult time coming up to a certain temperature quickly due to extremely cold outdoor temperatures, the “aux heat” indicator means that a secondary heat source (generally gas or electric) has been deployed.

What Does Aux Heat Mean on My Thermostat?

If your aux heat indicator is on, it means your heat pump needs a little help reaching its target temperature setting. Aux heat comes from the same heat source as emergency heat, but aux heat works together with your heat pump, so it’s less expensive than emergency heat. Typically, your heat pump will energize the auxiliary heat strip inside your secondary heating source to help reach its set temperature more quickly. Basically, if your heat pump is struggling to maintain its goal temperature, your aux heat will turn on and give your heat pump a boost.

Your thermostat determines when the auxiliary heat gets energized. When the temperature inside your home drops a certain amount below the goal temperature (usually 1.5-2 degrees), your thermostat energizes auxiliary heat. The aux heat indicator on your thermostat lets you know when this is happening. Aux heat will turn off once your home reaches the thermostat set point.

How to Use Your Heat Pump Thermostat Settings in Cold Temperatures

Both air exchange and geothermal heat pumps aren’t as efficient during extremely cold weather. This is because heat pumps must work extra hard to get your home up to its set temperature (and to maintain that temperature). This means your aux heat will run a lot more, costing you more money. Make sure that in the coldest months of the year you know how to use your heat pump thermostat in the most efficient way possible.

Tips for using your heat pump thermostat in winter:

• Only turn your heat up two degrees at a time to avoid using aux heat.
• Do NOT turn on the emergency heat setting unless it’s really an emergency (for example, your heat pump broke). Your aux heat works in tandem with your secondary heat source and your home’s heat pump. Turning on emergency heat means you’re relying completely on the secondary heat source, which is a lot more expensive than running aux heat.
• Call a professional if your thermostat indicates aux heat is running even after outside temperatures reach 40 degrees or higher

Call Aire Serv and Find the Goldilocks Zone

Is your home too hot? Is it too cold? Reach the Goldilocks Zone of “just right” with help from Aire Serv^®. Aire Serv is fully equipped to install and service all types of heat pumps along with all their components. Call (855) 512-2886 or request an appointment online to get started.