This Common Mistake Doubles Your Electricity Bill

One thermostat mistake can make electric heating much more expensive: leaving a heat pump set to Emergency Heat when the regular heat-pump mode is working.

Electric resistance heat can use roughly twice as much electricity as a heat pump for the same heating job. That does not mean this mistake will double every household’s entire electricity bill, but it can cause a major winter increase—especially in an all-electric home.

1. The Mistake: Using Emergency Heat as Normal Heat

A heat pump moves heat rather than creating all of it directly from electricity. Emergency Heat usually bypasses the heat pump and relies on a backup source, commonly electric resistance strips. Those strips work, but they can require substantially more electricity.

The U.S. Department of Energy says modern air-source heat pumps can reduce electricity use by about 50% compared with electric resistance furnaces and baseboard heaters. Put another way, resistance heat can use roughly twice the electricity of a heat pump for an equivalent heating load under suitable conditions.

👉 Read the Department of Energy heat-pump guidance

2. Why “Double” Does Not Apply to Every Total Bill

The headline describes a possible heating-cost effect, not a guarantee that every total utility bill will exactly double. Your result depends on outdoor temperature, insulation, thermostat settings, equipment efficiency, electricity rates, home size, and how much of the bill normally comes from heating.

A home with electric heating may see a dramatic jump. A home that heats with gas or uses little heat may see no effect from this particular mistake. Compare kilowatt-hour use—not just the dollar total—because rate changes and billing periods can also change the amount due.

3. Emergency Heat and Auxiliary Heat Are Not the Same

Emergency Heat is normally selected manually and disables or bypasses the outdoor heat-pump system. Auxiliary Heat is usually activated automatically when the heat pump needs help, such as during very cold weather or a large thermostat adjustment.

Brief automatic auxiliary-heat operation can be normal. Emergency Heat staying on because someone selected it—or auxiliary heat running constantly in mild weather—deserves attention.

4. When Emergency Heat Is Appropriate

Emergency Heat can protect your household when the regular heat pump cannot operate. Examples include an outdoor-unit failure, physical damage, a system fault, or a technician directing you to use backup heat until repairs are completed.

If the outdoor unit is damaged, making unusual noises, visibly iced beyond a normal defrost cycle, or not operating, avoid repeatedly resetting equipment. Use the safe backup recommended for your system and schedule service.

5. Large Thermostat Changes Can Trigger Backup Heat

Some heat-pump systems activate auxiliary resistance heat when the thermostat setting is raised several degrees at once. That can make an aggressive morning temperature recovery more expensive than a gradual change.

Use a thermostat designed and configured for heat pumps. Avoid copying a setback schedule meant for a furnace without checking your system’s guidance. The best schedule depends on the equipment, climate, controls, and household routine.

6. Portable Space Heaters Can Create a Similar Surprise

Most plug-in space heaters also use electric resistance heat. Heating one occupied room for a short period may be practical, but operating several heaters for many hours can add significant electricity use.

• Check the wattage on the product label.
• Multiply watts by hours used, then divide by 1,000 to estimate kilowatt-hours.
• Multiply kilowatt-hours by your electricity rate to estimate operating cost.
• Plug heaters directly into a wall outlet, following the manufacturer’s instructions.
• Keep heaters away from bedding, curtains, furniture, children, and pets.

7. Calculate the Cost Before Blaming One Appliance

Use this basic calculation:

Watts ÷ 1,000 × hours used × electricity rate = estimated cost

For example, a 1,500-watt heater used for eight hours consumes 12 kilowatt-hours. Multiply 12 by the price per kilowatt-hour shown on your bill. Actual costs vary, and a thermostat may cycle the heater rather than keep it at full power continuously.

8. Other Reasons an Electricity Bill Suddenly Jumps

• Colder or hotter weather than the previous billing period
• A rate increase or time-of-use pricing
• A longer billing cycle
• A malfunctioning HVAC system or water heater
• Heavy auxiliary-heat operation
• New appliances, guests, electric-vehicle charging, or added laundry
• A dehumidifier, pool pump, well pump, or heated pipe cable running longer
• An estimated meter reading followed by a correction

The U.S. Energy Information Administration reports that residential electricity use varies substantially by region and home type. Air conditioning, space heating, and water heating are among the largest household electricity uses.

👉 See how U.S. homes use electricity

9. Steps That Can Lower Heating Costs

• Return the thermostat to regular Heat mode when the heat pump is operating normally.
• Use a heat-pump-compatible thermostat and appropriate schedule.
• Replace or clean filters according to the system instructions.
• Keep supply registers and return vents clear.
• Seal obvious air leaks around doors and windows.
• Close fireplace dampers when the fireplace is not in use.
• Schedule service when auxiliary heat runs constantly or comfort drops.
• Ask the utility whether free energy assessments or efficiency kits are available.

10. When to Call the Utility or an HVAC Professional

Contact your electric utility when meter data, rates, billing dates, or estimated readings do not make sense. Ask for a daily or hourly usage history if your account provides one.

Call a qualified HVAC professional if the heat pump does not operate, the breaker repeatedly trips, the system emits a burning smell, ice does not clear during normal operation, auxiliary heat runs unusually long, or indoor temperatures cannot be maintained. Treat smoke, sparks, or an electrical burning odor as an urgent safety issue.

How to Find Free Energy-Saving Help

• Check your utility for free home-energy reports, online usage tools, or energy kits.
• Ask whether income-qualified weatherization or payment assistance is available.
• Search ENERGY STAR rebates by ZIP code.
• Look for state, local, and utility rebates before purchasing equipment.
• Use official government and utility sources rather than rebate ads that request upfront payment.

Helpful Energy Resources

• Department of Energy — Energy Savings
• ENERGY STAR Home Savings and Rebate Tools
• Department of Energy Home Upgrades
• EIA — Energy Use in Homes

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