Why Does Auxiliary Heat Make My Electric Bill Jump?

Why auxiliary heat costs so much

It comes down to how the heat is made. A heat pump moves heat from outside air into your home, which is efficient.

Auxiliary heat works differently. It uses electric heat strips that turn electricity straight into heat, much like a giant space heater.

Those strips draw a lot of power. So whenever they run, your meter spins faster and the bill climbs.

That is why a winter full of aux heat can feel like a shock when the bill arrives.

• The heat pump moves heat efficiently.
• Aux heat strips make heat by burning electricity.
• Strips draw far more power than the heat pump.
• More strip runtime means a higher bill.

When aux heat is supposed to run

Some aux heat is normal and expected. When it gets cold enough, often in the teens or low 20s, the heat pump cannot pull enough heat from the outside air alone.

The strips step in to help keep the house warm. Frederick gets cold snaps like this every winter.

Aux heat also kicks on for short bursts during defrost, or when you raise the thermostat a lot at once. A brief run in those cases is fine and not a sign of trouble.

• Normal in a hard cold snap, often the teens or 20s.
• Normal for short bursts during defrost.
• Normal when you raise the setpoint a lot at once.
• A short stretch in deep cold is expected in winter.

When the bill jump means a problem

Call for repair when aux heat runs more than it should. If it comes on in mild weather, runs nonstop, or the bill jumps with no cold snap to explain it, the heat pump is leaning on the strips too much.

Common causes are low refrigerant, a dirty or restricted system, a thermostat set up wrong, or a failing part in the heat pump. A technician finds why the heat pump is not carrying the load and fixes it, which brings the strips back to backup duty.

• Aux heat runs in mild weather, not just deep cold.
• The bill jumps with no cold snap to explain it.
• Causes: low charge, dirty system, wrong thermostat setup, or a failing part.
• Fixing the heat pump cuts how often the strips run.

What you can check first

Start with a few safe checks. Make sure the thermostat is set to heat and not emergency heat, since emergency heat runs the costly strips on purpose.

Set a steady temperature instead of big swings, which trigger the strips.

Check the filter and outdoor unit too. A dirty filter or an iced, blocked outdoor unit makes the heat pump weak, so the strips run more.

Replace the filter and clear the unit, then watch whether the aux heat backs off.

• Set the thermostat to heat, not emergency heat.
• Keep a steady setpoint instead of big jumps.
• Replace a dirty filter.
• Clear ice, snow, and debris from the outdoor unit.

How we help in Frederick

If aux heat runs too often or the bill jumped without a cold snap, call for heat pump repair. Tell us how cold it was, how the thermostat is set, and whether the heat feels weak.

If it only ran during a hard freeze, that is normal and you can leave it be. A fall tune-up checks the charge and controls so the heat pump carries more of the load on its own.

• Call if aux heat runs in mild weather or the bill spiked.
• Tell us the weather, thermostat setup, and how the heat feels.
• A fall tune-up keeps the heat pump doing more of the work.