Heat pumps are designed to efficiently heat and cool homes, but there are times when additional support is needed—especially in colder weather. Emergency heat, often called EM heat or auxiliary heat, is a backup heating mode that ensures comfort when temperatures drop significantly. While this function is crucial for maintaining warmth, it can also lead to higher energy bills if used excessively or incorrectly. So, understanding when a heat pump switches to emergency heat, how auxiliary heat works, and what it all means for your system’s health is essential.
What is EM Heat?
Emergency heat, or EM heat, is a feature found on most heat pumps that kicks in when the system’s regular heat isn’t sufficient to keep your home warm. This mode typically utilizes electric resistance coils or a secondary heat source to provide extra warmth. When outdoor temperatures fall below the efficient operating range for your heat pump, emergency heat automatically engages to prevent your home from losing warmth. The function is designed for occasional use and ensures your comfort when the heat pump alone can’t keep up.
What Does Auxiliary Heat Mean?
Auxiliary heat is similar to emergency heat but works differently. While both auxiliary and emergency heat add extra warmth, auxiliary heat activates automatically whenever the heat pump detects that it’s struggling to maintain the set temperature. This might occur when temperatures drop quickly or during a particularly cold spell. Auxiliary heat is the first line of support for the heat pump before it switches to emergency heat. In contrast, emergency heat is usually a manual setting used as a last resort or when the primary heat pump system needs repair.
When Does a Heat Pump Switch to Emergency Heat?
The switch to emergency heat can happen automatically if your system is equipped to recognize when outdoor temperatures fall below a certain point, usually between 32°F and 40°F. Here’s when and why a heat pump may switch to emergency heat:
- Severe Cold Weather: When temperatures plummet, the heat pump struggles to extract enough heat from the outside air. At this point, the heat pump’s built-in sensors activate emergency heat.
- System Malfunction: If a component in the heat pump fails, such as the compressor or outdoor unit, the system will activate emergency heat to keep your home warm while bypassing the malfunctioning part.
- High Heating Demand: When the indoor temperature needs to increase rapidly, emergency heat may engage to help the heat pump reach the desired warmth more quickly. However, this usage should be limited since emergency heat is less efficient.
Homeowners should keep an eye on the system when emergency heat is active, as it uses more electricity than standard heat pump operation, leading to higher energy costs. Therefore, only use it when necessary, such as during extreme weather or while awaiting repairs.
When to Use Emergency Heat
Emergency heat is intended for specific scenarios, and using it at the wrong time can lead to unnecessary expenses. Here are the instances when using emergency heat may be beneficial:
- If the Heat Pump is Malfunctioning: If your heat pump isn’t heating as it should due to a mechanical problem, switch on emergency heat and call for repairs. Using EM heat in this case keeps your home comfortable while allowing the heat pump to remain off until it can be serviced.
- During Extreme Cold Conditions: In freezing temperatures, auxiliary heat will often engage to help the heat pump keep up, but if temperatures are particularly low and you notice the house isn’t warming up, consider manually switching to emergency heat. Just remember to revert once temperatures rise above freezing.
- As a Temporary Backup: Emergency heat is also a useful temporary solution if you’re having new components installed or repaired. This way, you can maintain warmth without risking additional strain on a partially functional system.
For most homeowners, emergency heat should only be used in emergencies, hence its name. Switching to emergency heat unnecessarily leads to excessive electricity usage and higher utility bills, making regular use counterproductive.
Is it Bad if Auxiliary Heat Comes On?
Auxiliary heat, unlike emergency heat, is not usually a cause for concern when it activates on its own. Auxiliary heat is a part of the system’s normal operation and acts as a support function during cold weather. When auxiliary heat comes on, it typically means your heat pump needs additional help to reach the set temperature due to lower-than-normal outdoor temperatures.
However, if you notice auxiliary heat frequently coming on when outdoor temperatures aren’t exceptionally low, it might indicate an issue with your system’s efficiency. In this case, you may benefit from a professional inspection to ensure your heat pump is operating optimally.
Tips for Managing Emergency and Auxiliary Heat Usage
Using emergency and auxiliary heat effectively requires a balance between comfort and efficiency. Here are some tips for managing their usage:
- Set a Reasonable Temperature: During winter, set your thermostat to a comfortable yet energy-saving temperature. Avoid dramatic temperature increases, as these can trigger auxiliary heat unnecessarily.
- Check the Defrost Cycle: Heat pumps automatically go into a defrost mode to prevent freezing, during which auxiliary heat may activate. If you notice frequent defrost cycles or increased auxiliary heat usage, have the defrost system inspected.
- Ensure Proper Insulation: A well-insulated home keeps heat from escaping, allowing your heat pump to work efficiently. This reduces the need for auxiliary or emergency heat in colder months.
- Regular Maintenance: Regular heat pump maintenance is essential for minimizing auxiliary and emergency heat use. A well-maintained system can better handle temperature drops without switching to backup heat.
- Monitor Your Utility Bills: If you notice an unexplained spike in heating costs, it could be due to excessive auxiliary or emergency heat usage. If so, consult a heating professional to assess your system for efficiency.
Keeping Your Heat Pump in Optimal Condition
In conclusion, understanding when a heat pump switches to emergency heat, what auxiliary heat means, and how these functions operate is essential for managing your home’s comfort and energy efficiency. Emergency heat is invaluable during extreme cold or when a heat pump needs repair, but should only be used when necessary. Meanwhile, auxiliary heat provides support and is an automatic function that can help the heat pump reach desired temperatures during cold spells.
For Charleston homeowners, staying on top of regular heat pump maintenance is key to ensuring your system’s auxiliary and emergency heat work effectively when needed. By keeping your heat pump in optimal condition, you can enjoy consistent warmth and reduce your reliance on energy-intensive backup heating modes.
For professional heat pump maintenance and service, contact Charleston Heating & Air today. Our expert team is here to help keep your system running smoothly, no matter the season.
