Heat Pump Stuck on Emergency Heat? What It Means for Your Raleigh Home

Your electric bill just arrived, and it is noticeably higher than last month, even though nobody touched the thermostat. Then you notice "EM Heat" or "Emergency Heat" lit up on the display and cannot remember turning it on. The house still feels warm, so what is going on?

At Heating + Air Paramedics, this is one of the most common winter calls we get from homeowners in Raleigh, NC. Heat pumps are the go-to heating system across the Triangle, and when one ends up running on emergency heat for days or weeks, the house can stay comfortable while your energy costs climb. Here is what emergency heat means, why it happens, and what to do about it.

A heat pump does not burn fuel to make heat. In heating mode, it pulls heat from the outdoor air and moves it inside using refrigerant, a compressor, and the outdoor coil. That efficiency makes heat pumps a great fit for our mild North Carolina winters.

Every heat pump system also has a backup heat source. In most homes, that is a set of electric resistance heat strips inside the indoor air handler. In a dual-fuel system, the backup is a gas furnace instead. If yours is a dual-fuel setup, our furnace repair team in Raleigh services that side of the system too.

Emergency heat, often shown as "EM Heat" or "E-Heat," tells your system to shut the heat pump off completely and warm the house using only the backup source. It exists for one reason: keeping your family warm when the heat pump itself cannot run.

These two settings look similar on the thermostat, but they work very differently:

• Auxiliary heat (Aux Heat): Your thermostat turns on backup heat automatically to help the heat pump, such as during a defrost cycle, on a very cold morning, or when you raise the temperature several degrees at once. The heat pump keeps running, and aux heat shuts off once it is no longer needed.
• Emergency heat (EM Heat): On most systems, this mode is selected manually at the thermostat. The heat pump stays off, and backup heat does all the work until someone switches the mode back.

Seeing "Aux" for short stretches on cold days is normal. Seeing "EM Heat" stay on, or seeing aux heat run almost nonstop on mild days, is a sign that something needs attention.

Emergency heat uses electric resistance heat, which costs more to run than a properly working heat pump. Resistance heat works much like a space heater or toaster, turning electricity directly into heat. A heat pump simply moves heat that already exists outdoors, so it delivers the same comfort while using considerably less electricity.

That is why the first warning sign for many homeowners is not a cold house but a spike in the electric bill. Because backup heat can usually keep up on milder winter days, the problem can go unnoticed for an entire billing cycle.

A few quick checks can tell you whether this is a simple setting issue or a repair:

• Check the thermostat mode. If it is set to EM Heat and you have no reason to think the heat pump is broken, switch it back to Heat and give the system several minutes to respond.
• Look at the outdoor unit. Is the fan spinning and the unit running? Is the coil covered in thick ice?
• Check your breakers. The outdoor unit usually has its own breaker plus a disconnect near the unit. If a breaker has tripped, you can reset it once. If it trips again, leave it off and call us, because repeated tripping points to an electrical fault.
• Replace a dirty air filter. Restricted airflow makes the whole system work harder.
• Clear debris around the outdoor unit. Leaves, branches, and yard clutter can block airflow across the coil.

Avoid chipping ice off the coil with tools, since that can damage the fins and refrigerant lines. And if the heat pump will not run in Heat mode, it is perfectly fine to leave emergency heat on to keep your home warm until help arrives. That is exactly what it is for.

Contact a professional if you notice any of the following:

• The outdoor unit will not start after switching back to Heat
• A breaker trips again after you reset it
• Ice covers the outdoor coil and does not clear on its own
• The system blows cool air while set to Heat
• Aux heat runs constantly, even on mild days
• Your electric bill has jumped with no clear explanation
• You hear buzzing, grinding, or rattling from the outdoor unit

Our licensed technicians diagnose and fix heat pumps of all makes and models, and with same-day appointments and 24/7 emergency HVAC services across Raleigh and the Triangle, we work to get your heat pump doing the heating again as quickly as possible.

• Schedule seasonal tune-ups. We recommend two visits a year, one before summer and one before winter, so problems with capacitors, defrost controls, and refrigerant levels are caught early.
• Change filters regularly. Clean filters protect airflow and reduce strain on the system.
• Use the right thermostat setting. Leave the system in Heat during cold snaps. Your heat pump will bring on aux heat automatically when it needs help.

A heat pump stuck on emergency heat is your system telling you something is wrong. Whether the fix is a thermostat setting or a failed outdoor part, the sooner it is addressed, the sooner your home is heated efficiently again.

Heating + Air Paramedics provides fast, honest heat pump service to homeowners throughout Raleigh, NC, and the surrounding communities, with upfront pricing and no hidden fees. Call us at 919-295-9675 or request service online to schedule your appointment today.