Auxiliary Heat: What Is It?

marketing08265
Nov 24
2 min read

Auxiliary heat is a backup system for heat pumps that provides extra warmth when the main system can't keep up, typically in very cold weather (below about

35−40°F), when the heat pump is in defrost mode, or if the thermostat is adjusted by more than 2−3° at once. It uses less efficient electric resistance heating and can run up your energy bill if it comes on frequently or is running constantly.

When auxiliary heat turns on

Cold weather: When temperatures drop below about
35−40°F, the heat pump struggles to pull enough heat from the outside air.
Significant thermostat changes: If you increase the temperature setting by more than
2−3° at a time, auxiliary heat will activate to reach the new target temperature faster.
Defrost mode: During icy conditions, a heat pump will periodically switch to a defrost cycle to remove frost from the outdoor unit. The auxiliary heat turns on to keep your home warm during this brief period.

Why it's important to manage

Efficiency: Auxiliary heat is less energy-efficient than the heat pump, so it can lead to higher energy bills if it runs too often.
System health: Over-reliance on auxiliary heat can put extra strain on the system's components, potentially leading to faster breakdowns over time.

What to do if auxiliary heat seems to be on too much

Check the thermostat: Make sure it hasn't been accidentally set to "Emergency Heat" or bumped up significantly.
Gradually adjust the temperature: Avoid making large, sudden temperature increases; adjust your thermostat in small increments (e.g.,
1° at a time).
Watch for problems: If auxiliary heat is running when it's not cold out or the house is already warm, there could be a problem. Contact a professional to check for issues like a faulty fan motor, bad compressor, or thermostat malfunction

Signs your heat pump may need repairs

It’s important to perform regular maintenance checks to ensure your heat pump is working properly, especially as the colder months roll in. There are a few DIY fixes that can save you some money, but most repairs should be handled by a professional comfort technician.

Check out the Steinhardt Comfort Shield for maintenance checks twice a year, discounts on products, and even FREE Service Calls!

Heat pump will not turn on

Make sure your heat pump is receiving power and check that your thermostat is set to heat. If everything is set correctly, your heat pump start capacitor may be broken or there could be an issue with your reversing valve.

Heat pump not heating home

See if your unit is blocked by snow, ice, or fallen shrubbery. Your air filter may also need to be cleaned or changed if it is clogged and unable to efficiently let air through.

If you notice none of this is working, call Steinhardt Heating and Air Conditioning at 812-866-2400 for a thorough check!