When the temperature drops, you rely on your heat pump to keep your home warm. You may have noticed a setting on your thermostat labeled “Emergency Heat” or “EM Heat.” It’s a feature many don’t fully understand, and as a result, it’s often ignored entirely or used incorrectly. You may need to activate it manually if your heat pump malfunctions. Here, we’ll explain what emergency heat does, when you should activate it, and when to leave it off. This will help you avoid high energy bills, prevent unnecessary wear on your system, and keep you warm.
How Heat Pumps Normally Work
Unlike a furnace that generates heat, a heat pump transfers heat from one place to another. This is an extremely energy-efficient method for heating your home. In heating mode, the system extracts heat from the air outside and transfers it indoors. Even in cold weather, outdoor air contains enough thermal energy for the heat pump to work efficiently.
In Sterling’s climate, heat pumps handle most of the heating load well for much of the year. However, as temperatures dip well below freezing, the system’s ability to extract heat decreases. While a cold-climate heat pump can work efficiently down to around 15 degrees below zero, standard heat pumps feature auxiliary heating.
What Emergency Heat Does
Emergency heat is a backup system for your heat pump. This is for when your heat pump malfunctions. You manually tell the system to stop using the outdoor unit entirely and rely only on the secondary heating source. This secondary source is typically either electric resistance heat strips installed inside the air handler or a furnace.
This mode bypasses the heat pump’s outdoor components. Since emergency heat is less energy efficient, using it for extended periods can result in significantly higher utility bills.
Emergency Heat vs. Auxiliary Heat
It’s easy to confuse emergency heat with auxiliary heat, but they’re not the same. Auxiliary heat automatically turns on when the heat pump alone can’t keep up with the home’s heating demand. For example, if the temperature outside drops, the heat pump may need extra help maintaining the set indoor temperature. The thermostat will signal the backup heat source to kick in temporarily. Once the temperature stabilizes, the auxiliary heat turns off, and the heat pump takes over again.
Emergency heat, on the other hand, requires you to manually switch the thermostat to EM Heat. Doing this tells the system to shut off the heat pump and rely only on the backup heat source. You should only use this setting under specific circumstances, which we’ll cover next.
When You Should Use Emergency Heat
Emergency heat is important, but it is not meant for everyday use. You should only activate this mode under certain conditions.
When the Heat Pump Breaks Down
Use emergency heat if your outdoor heat pump unit stops working due to a mechanical issue, electrical failure, or a refrigerant problem. This ensures your home doesn’t go without heat. By switching to EM Heat, you rely on the backup system until a technician can repair the unit. This can be a lifesaver during freezing temperatures. You stay comfortable and avoid frozen pipes and other cold-weather problems.
When Ice Accumulates on the Outdoor Unit
Heat pumps typically defrost themselves automatically, but severe winter storms can sometimes overwhelm this function. When ice builds up on the outdoor coils, the system may shut down to protect itself. Switching to emergency heating keeps your home warm while preventing further damage to the equipment.
When Extreme Cold Overwhelms the Heat Pump
Sterling winters can bring cold temperatures that are well below the heat pump’s efficient operating range. In these rare cases, switching temporarily to emergency heat may keep your home more comfortable. However, it’s usually better to rely on auxiliary heat or a properly configured dual-fuel system.
When You Should Avoid Using Emergency Heat
Since emergency heat often uses electric resistance coils, it consumes far more energy than normal heat pump operation. Leaving it on unnecessarily can cause your utility bills to skyrocket. Avoid switching to emergency heat if your heat pump is working normally and only requires auxiliary support during a temporary cold spell.
You should also avoid using it to try to heat your home faster. EM Heat doesn’t speed up heating; it just forces the system to rely on a more expensive backup source. Don’t use this mode if you haven’t confirmed that the heat pump is malfunctioning. You shouldn’t use the emergency setting unless there’s a clear reason to bypass the outdoor unit entirely.
How Emergency Heat Fits Into Dual-Fuel Systems
You can also use dual-fuel systems, which use a gas furnace as well as a heat pump. These systems switch between the two heat sources to maximize efficiency. In mild weather, the heat pump will provide energy-efficient heating. When temperatures drop to a set balance point, the system turns off the heat pump and lets the furnace take over. This transition happens automatically and is often more cost-effective than using electric resistance backup.
Emergency heat in a dual-fuel system typically refers to manually switching the thermostat to run the furnace exclusively. This might be necessary if the heat pump breaks down and needs emergency service. Since natural gas furnaces generally cost less to run than electric resistance heating, dual-fuel setups offer a cost-effective and reliable backup solution.
The Cost Implications of Using Emergency Heat
Emergency heat keeps you warm in a pinch, but it comes at a cost. Electric resistance heating uses far more energy than a heat pump. A heat pump can deliver two to three units of heat for every unit of electricity consumed. A resistance heating method delivers one unit of heat for each unit of electricity.
If you run emergency heat for days at a time, your utility bill can climb rapidly. Dual-fuel systems eliminate this problem by switching to gas heat instead of electric strips. Even then, running the system in emergency mode unnecessarily is not ideal. If you find yourself relying on EM Heat frequently, it may be a sign that your heat pump needs service. Alternatively, your home’s insulation may need improvement, or your system may not be sized correctly for your home.
The Role of Professional Maintenance
Routine maintenance is important when it comes to preventing the need for emergency heat. A well-maintained heat pump can handle colder temperatures more efficiently, defrost itself properly, and run reliably throughout the winter. Meade’s Heating and Air recommends scheduling annual heating system maintenance before the winter season begins. During a maintenance session, our team will check refrigerant levels, clean coils, and inspect electrical components. We also test defrost cycles and verify that backup heating functions correctly.
Smart Thermostats and Emergency Heat
Many newer thermostats and smart controls automatically detect when your heat pump needs auxiliary or emergency heat. They can send alerts when something goes wrong, allowing you to act quickly before issues have the chance to escalate. Smart thermostats also make it easier to manage dual fuel systems. They will switch between the heat pump and the furnace based on the outdoor temperature. This ensures that you always use the most cost-effective option without manual intervention.
Consult with Meade’s Heating and Air for Reliable Heating
Emergency heat serves as a valuable backup option, but it’s not something to use every day. When you understand how it works and when to use it, you can stay warm while avoiding high energy bills. At Meade’s Heating and Air, we provide heat pump installation, furnace repair, and maintenance. If you want your heat pump to run efficiently and reduce the chance of relying on emergency heat this winter, contact us] today.
