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When To Use Emergency Heat On Heat Pump

A heat pump is a good way to keep your residence comfortable throughout the year, but when extreme temperatures arrive, the heating system can struggle to keep up.


In such cases, your heat pump may switch to emergency heating mode. But when does this happen?


In this article, we will discuss when a heat pump switches to emergency heating mode and answer any questions you may have about this process.


What is a heat pump?

A heat pump is like a reversible air conditioner and heater.


Its operation involves extracting heat from the outdoors and using that heat to warm the indoors.


When the temperature becomes extremely cold, the heat pump may switch to emergency heating mode.


This emergency setting helps ensure that your home stays warm even in exceptionally cold outdoor conditions.


What is emergency heating?

Emergency heating is a setting in the heat pump that helps keep the indoor temperature warm when the heat pump cannot handle extremely cold temperatures.


Professionals also refer to emergency heating as EM heating, auxiliary heating, or aux heating.


It uses emergency or auxiliary heating elements such as resistance heating (like electric heating strips) or auxiliary gas furnaces to generate additional warmth, ensuring your home remains comfortable.


Emergency heating is typically used when the outdoor temperature drops below freezing, and the heat pump cannot provide sufficient heat for your home.


Both systems must be connected to their respective power sources for emergency heating to work.


Additionally, emergency heating consumes more energy than normal heating, leading to an increase in utility bills.



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Factors influencing the use of emergency heating by a heat pump

Outdoor Temperature: A heat pump is designed to work most efficiently at moderate temperatures. As the outdoor temperature drops, the heat pump’s ability to extract heat from the outside air diminishes.


Beyond a certain point (typically between 20-30 degrees Fahrenheit), the heat pump may be unable to extract enough heat from the outdoor air to maintain the desired indoor temperature.


At this point, the emergency heating source will be activated to supplement the heat pump’s output.


Temperature Setpoint: The temperature setpoint is the ideal temperature on the heat pump thermostat.


When the heat pump is operating normally, it maintains this setpoint by extracting heat from the outdoor air and circulating it indoors.


However, if the outdoor temperature is too low or the heat pump is not functioning properly, it may struggle to maintain the setpoint.


In such cases, the emergency heating setting is activated to supplement the heat pump’s output and raise the temperature to the desired setpoint.


When the emergency heating indicator light is displayed on the thermostat screen, you’ll know this is happening.


Users can adjust the thermostat to a lower setpoint. This reduces the amount of heat required to reach the set temperature and reduces the likelihood of auxiliary heating activation.


However, it’s essential to consider the trade-offs, as lower temperatures can make occupants uncomfortable on cold days.


Usage and Maintenance: The usage lifespan and maintenance of the heat pump are crucial factors in determining when to activate the emergency heating mode.


Over time, internal components may wear down or become damaged, leading to reduced heating efficiency or the switch to emergency mode to maintain a comfortable temperature.


Regular maintenance is essential to keep the heat pump operating efficiently.


Air Filter or Duct System Blockages or Damage: If the air filter or duct system is blocked or damaged, it can also trigger the heat pump to switch to auxiliary heating.


A clogged or damaged air filter restricts the airflow of the heat pump, reducing its ability to extract heat from the outside air.


Similarly, if the duct system is blocked or damaged, the indoor circulating air can also be restricted.


Signs that the heat pump may be switching to emergency heating


Several signs indicate that the heat pump may be switching to emergency heating:


Increased Utility Bills: If your heating system frequently switches to emergency heating, it can lead to higher energy usage and increased utility bills.


Continuous Operation of Backup Heating System: When the emergency heat source is activated, it will run continuously until the heat pump can maintain the desired temperature setpoint.


If the backup heat source runs continuously, it may indicate that the heat pump is not functioning correctly.


Reduced Airflow: When the heat pump is operating normally, there should be a continuous flow of warm air from the vents.


If the airflow is reduced, it may be due to a clogged or damaged air filter or duct system.


No Change in Indoor Temperature During Operation: If the heat pump is running, but there is no change in the indoor temperature, it may indicate that the heat pump is not operating correctly or is unable to extract sufficient heat from the outside air.

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In this case, the auxiliary heating source will be activated to supplement the heat pump’s output.


By paying attention to these signs, homeowners can identify when the heat pump may be switching to auxiliary heating and take measures to address the issue before it becomes more significant and costly.


Factors that contribute to heat pump switching to emergency heating

Regular Maintenance and Cleaning: This includes tasks such as cleaning the outdoor coils, checking refrigerant levels, and lubricating moving parts. Refer to the manufacturer’s manual for more maintenance intervals.


Replacing Air Filters and Cleaning the Duct System: Dirty or clogged air filters reduce the airflow of the heat pump, leading to decreased efficiency. Similarly, a dirty duct system can have the same effect.


Regularly replacing air filters and checking and cleaning the duct system helps maintain proper airflow and improves efficiency.


Improving Home Insulation: Insulating the home helps reduce heat loss through walls, floors, and ceilings.


This helps the heat pump maintain the desired temperature setpoint even in lower outdoor temperatures.


Proper insulation can lower energy usage and costs and reduce the likelihood of the HVAC system switching to emergency heating mode.


Upgrading Your Heat Pump: As heat pumps age, their efficiency decreases, and the need for repairs may increase. Consider replacement when repair costs reach around 50% of replacement costs.


Homeowners can ensure the heat pump operates as efficiently as possible by upgrading to newer, more efficient models available with today’s technology.


By following these steps, homeowners can reduce the likelihood of the heat pump frequently switching to emergency heating.


Consulting the manual, seeking expert advice, and ensuring maintenance is performed by qualified professionals are always essential.


In conclusion:

Understanding the factors that can cause the heat pump to switch to emergency heating and how to prevent this from happening is crucial.


By knowing when and why emergency heating may be needed, you can take measures such as regular maintenance and cleaning, replacing air filters, upgrading insulation, and upgrading the heat pump to keep the system operating efficiently without relying on emergency mode too often.


If you suspect issues with your system, the best course of action is always to contact professional HVAC technicians.


They can diagnose any potential problems and ensure your primary heating system operates smoothly and efficiently.

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