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HVAC
Updated August 12, 2025
Auxiliary heat on
Auxiliary heat kicks in when your main heater can’t keep up, giving you extra warmth on chilly days. It’s like a backup buddy for your heating system!
Category
HVAC
Use Case
Provides supplemental heating when the primary heat source is insufficient.
Key Features
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Secondary Heating System Activation
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Boosts Indoor Temperature Quickly
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Supplements Primary Heat Source
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Kicks In During Extreme Cold
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Uses Additional Energy Sources
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Ensures Consistent Warm Airflow
In Simple Terms
What it is
Auxiliary heat is like a backup helper for your home’s heating system. When your main heater (usually a heat pump) can’t keep up with freezing temperatures, the auxiliary heat kicks in to give it a boost. Think of it as calling in reinforcements when the main team is struggling.
Why people use it
People rely on auxiliary heat because it keeps their homes warm when the weather gets extremely cold. Without it, your heating system might work too hard or fail to maintain a comfortable temperature. Here’s why it’s helpful:
It prevents your home from getting too cold when the main heater isn’t enough.
It ensures consistent warmth during winter storms or sudden temperature drops.
It reduces strain on your primary heating system, helping it last longer.
Basic examples
Imagine you’re wearing a light jacket on a chilly day. If the wind suddenly gets stronger, you’d add a sweater to stay warm—that’s like auxiliary heat stepping in. Here’s how it works in real life:
On a freezing night, your heat pump runs nonstop but can’t warm the house. Auxiliary heat turns on automatically to help.
During a power outage or extreme cold snap, auxiliary heat ensures your family stays cozy.
If you’ve ever felt a blast of extra-warm air from your vents on the coldest days, that’s auxiliary heat doing its job.
Auxiliary heat is like a backup helper for your home’s heating system. When your main heater (usually a heat pump) can’t keep up with freezing temperatures, the auxiliary heat kicks in to give it a boost. Think of it as calling in reinforcements when the main team is struggling.
Why people use it
People rely on auxiliary heat because it keeps their homes warm when the weather gets extremely cold. Without it, your heating system might work too hard or fail to maintain a comfortable temperature. Here’s why it’s helpful:
Basic examples
Imagine you’re wearing a light jacket on a chilly day. If the wind suddenly gets stronger, you’d add a sweater to stay warm—that’s like auxiliary heat stepping in. Here’s how it works in real life:
Technical Details
What it is
Auxiliary heat, often labeled as "Aux Heat" on thermostats, is a secondary heating system in heat pumps designed to supplement primary heating when outdoor temperatures drop too low for the heat pump to operate efficiently. It falls under the category of backup or emergency heating systems, typically using electric resistance heating strips or a gas furnace.
How it works
When a heat pump cannot extract sufficient heat from cold outdoor air (usually below 35–40°F), auxiliary heat activates to maintain indoor comfort. The thermostat triggers the auxiliary system automatically, either in stages or as a single unit, depending on the temperature differential. Electric resistance coils generate heat directly, while gas furnaces ignite burners to produce warm air. This mechanism ensures consistent heating despite extreme cold but consumes more energy than the heat pump alone.