Is Your Heat Pump Secretly Draining Your Bank Account? The Hidden Culprit Behind Sky-High Electric Bills

When homeowners see their electric bills double or even triple during winter months, they often blame the cold weather. However, the real culprit might be lurking in plain sight: auxiliary heat overuse. This common yet misunderstood problem can turn an energy-efficient heat pump into an electricity-guzzling monster, leaving families struggling with unexpected financial strain.

Understanding Auxiliary Heat and Its Purpose

Auxiliary heat serves as a backup heating system for heat pumps when outdoor temperatures drop too low for efficient operation. It kicks in when your air source heat pump can’t extract enough warmth from the outdoor air to maintain your desired indoor temperature. This often happens during very cold temperatures when air source heat pumps struggle to perform at their expected energy efficiency. Unlike primary electric heat pumps, which transfer heat from the outside air to indoor living areas, auxiliary heat uses electric resistance coils or a gas furnace (for dual-fuel heat pump systems) to generate heat directly.

Auxiliary heat is a secondary heating function your thermostat automatically switches to when it’s too cold outside for your heat pump to extract warmth from the air. This type of heating is often triggered when the outdoor temperature drops to near or below-freezing temperatures. Under normal circumstances, this system should activate only when necessary and shut off once your home reaches the desired temperature.

The Financial Impact of Auxiliary Heat Overuse

The cost difference between heat pump operation and auxiliary heat is staggering. Continuous use of auxiliary heating in emergency mode can cause a noticeable spike in your energy bills—sometimes increasing them by as much as 50%! In some cases, homeowners have reported bills jumping from $175 to over $700 in a single month when auxiliary heat systems malfunction.

From the link above, you know a heat pump is two to four times more efficient than your backup electric heat. If your heat pump compressor fails and your backup heat takes over, the heat pump fan never shuts off and 6 weeks later you get a high electric bill, three times what it should be. This efficiency gap explains why auxiliary heat overuse can be so financially devastating for homeowners.

Common Control Problems That Trigger Overuse

However, if the heat pump runs for more than 15 to 30 minutes and the temperature doesn’t increase, the thermostat will typically signal the heat pump to shut off and switch over to auxiliary heat so that the home stays sufficiently warm. When this system malfunctions, several control problems can emerge:

• Thermostat Misconfiguration: This is because when the temperature inside your home drops below the goal temperature you’ve set the thermostat to, your thermostat energizes auxiliary heat. This commonly takes place once the indoor temperature on your thermostat reaches 2-3 degrees colder than the set indoor climate temperature. Improperly programmed thermostats may activate auxiliary heat too frequently.
• Temperature Setting Issues: More often than not, the aux heat is coming on because the temperature in the home is set too high. You are asking your HVAC system to work too hard to maintain a comfortable temperature. Setting the thermostat for somewhere between 62-68 degrees is all you should need to do to get the problem under control.
• Defrost Cycle Problems: I have come to the conclusion that the Defroster control board is turning on auxiliary heat and also air conditioning while leaving the outdoor unit’s FAN turning. This goes on for long periods of time. Malfunctioning defrost controls can keep auxiliary heat running unnecessarily.
• Heat Pump Component Failures: The HP isn’t working correctly and the electric elements doing the heating is the reason for the $500 spike in the bill. When heat pump components fail, the system defaults to auxiliary heat without the homeowner’s knowledge.

Warning Signs of Auxiliary Heat Problems

Recognizing the symptoms of auxiliary heat overuse can save homeowners hundreds of dollars. Key indicators include:

• The ecobee thermostat shows the following error: “In the past 24 hours the auxilary heat has been running for more than 180 minutes”. Modern thermostats often display warnings when auxiliary heat runs excessively.
• High energy bills: Pay close attention to your monthly energy bills. Sudden cost increases may indicate a problem with your AUX heat.
• However, temperatures of 50–60 degrees shouldn’t require AUX heat in a correctly functioning HVAC system. If auxiliary heat activates during mild weather, there’s likely a control problem.
• The downstairs unit, however, always has the red light on showing auxiliary heat. Even when its not running and just starts up at 1* less than the setting it goes right in to the auxiliary heat.

Professional Solutions and Prevention

When auxiliary heat problems persist, professional intervention becomes necessary. Your installers don’t know service. You need to get a tech that knows heat pumps. Qualified technicians can diagnose and resolve various issues, from thermostat recalibration to heat pump component replacement.

For homeowners in Charleston, West Virginia, and surrounding Kanawha County areas, Fellowship Heating, Cooling, and Refrigeration understands the unique climate challenges that affect HVAC systems. We understand West Virginia’s climate challenges and what it takes to keep HVAC systems running efficiently through hot, humid summers and cold winters. Our technicians are licensed, insured, and trained on all major HVAC brands. We’ve built our reputation on straight talk, fair pricing, and showing up when we say we will.

Professional heat pump repair services can address control problems before they result in costly electric bills. With Fellowship, you’re promised expert heating and cooling services with no hidden fees and results that last. Our work is backed by warranties and certified expertise. Know your costs upfront, no surprises.

Taking Control of Your Energy Costs

Don’t let auxiliary heat overuse drain your finances. One thing you can do to decrease the amount of time your system is running is to check your filter! A dirty filter increases the amount of time your system has to run and can increase your utility bills. Simple maintenance steps, combined with professional diagnostics when problems arise, can restore your heat pump’s efficiency and keep your electric bills manageable.

Understanding auxiliary heat control problems empowers homeowners to take proactive steps. Whether it’s adjusting thermostat settings, scheduling regular maintenance, or calling for professional repairs when warning signs appear, addressing these issues quickly can prevent financial strain and ensure comfortable, efficient heating throughout the winter months.