What is EM Heat?
EM heat, or emergency heat, is a backup heating system designed to keep your home warm when your primary heat source, typically a heat pump, can no longer function efficiently. This feature, often labeled as "emh on thermostat", becomes essential during extreme cold weather or if the heat pump requires repair, ensuring your home stays comfortable.
How Does EM Heat Function?
A typical heat pump works by extracting heat from the air outside—even during cold weather—and transferring it indoors. This process is efficient and effective for most winter conditions. However, when outdoor temperatures drop too low, usually around 30°F or below, the heat pump struggles to perform efficiently.
In such scenarios, your system may automatically switch to emergency heat. Alternatively, you can manually activate the setting on your thermostat when your heat pump isn't working as it should. Emergency heat relies on a secondary heat source, such as electric resistance heating or a gas furnace to maintain warmth. While reliable, this backup method is less efficient than the heat pump's standard operation.
When Does a Heat Pump Switch to Emergency Heat?
In most cases, your heat pump automatically transitions to emergency heat under specific conditions:
Extremely Low Temperatures: During severe cold spells, your heat pump may struggle to extract heat from the air outside. Emergency heat activates to provide the additional warmth your home needs.
System Malfunction: If the heat pump becomes damaged or stops working, emergency heat is a fail-safe to keep your home comfortable.
Ice or Frost Build-Up: When frost or ice forms on the outdoor unit, the system may require time to defrost. Emergency heat ensures consistent indoor heating during this process.
These transitions are typically automatic, but understanding when to activate EM heat manually can help you handle unexpected heating challenges.
When Should You Manually Turn on Emergency Heat?
It's important to recognize when manually activating emergency heat is necessary. While your thermostat is designed to handle most situations automatically, some circumstances may require your intervention. For example:
If your heat pump stops functioning altogether due to mechanical failure, switching to EM heat ensures uninterrupted warmth until repairs can be made. Similarly, during an unusually cold night when your heat pump fails to keep up, manually activating emergency heat provides supplemental warmth.
Consider a homeowner in a cold climate who wakes up to a barely above-freezing house. Upon inspection, they noticed that the heat pump wasn't functioning correctly. Switching to emergency heat temporarily resolves the issue, keeping their home livable until an HVAC technician arrives.
What Does Emergency Heat Mean for Energy Consumption?
One of the most significant considerations with emergency heat is its impact on energy use. Unlike the regular heat pump mode, which operates efficiently by transferring heat from the air, EM heat relies on energy-intensive systems like electric resistance heaters or gas furnaces. This can significantly increase your energy bills.
For example, running your heat pump in standard mode might cost $0.50 per hour, but activating emergency heat could raise that cost to $2.00 per hour or more, depending on your system. This stark difference underscores why EM heat should only be used when absolutely necessary.
Emergency Heat vs. Heat Pump Mode: Key Differences
Understanding the differences between these modes helps you make informed decisions about your home's heating:
Heat Pump Mode: Operates by extracting heat from outside air, even in cooler temperatures. It's highly energy-efficient and the preferred mode for everyday conditions.
Emergency Heat Mode: Utilizes a secondary heating system, bypassing the heat pump entirely. While reliable for extreme cold or equipment failure, it consumes more energy.
Both modes have roles, but optimizing your system's performance requires knowing when to rely on each.
Addressing Misconceptions About Emergency Heat
Many homeowners mistakenly believe emergency heat is meant to be used whenever the temperature drops below freezing. It's designed as a backup for situations where the heat pump cannot perform effectively. Overuse of EM heat increases energy costs and places unnecessary strain on your heating system.
Another common myth is that emergency heat warms a home faster than the heat pump. While EM heat provides consistent warmth, the heating speed depends on your system's overall capacity, not the mode you select.
Maintenance Tips to Minimize EM Heat Usage
To reduce reliance on emergency heat, ensure your heating system is well-maintained. Regularly cleaning or replacing air filters can improve efficiency and prevent malfunctions. Additionally, schedule routine HVAC inspections to identify potential issues before they escalate.
Proper insulation also plays a critical role in reducing energy consumption. By sealing drafts and insulating your home effectively, you can keep warm air inside and minimize the load on your heating system. For example, sealing gaps around windows and doors can significantly lower the likelihood of needing EM heat during mild cold weather.
How to Use the Emergency Heat Setting on Your Thermostat
If you need to activate emergency heat manually, follow these steps:
Locate the emergency heat setting on your thermostat, usually labeled as "EM Heat" or "Aux Heat."
Switch the thermostat from "Heat" to "EM Heat." This setting will bypass the heat pump and rely on the backup heating source.
Monitor the system to ensure the secondary heating source is functioning correctly.
If you're unsure about your system's settings or functionality, consult a technician at MR.HVAC can provide clarity and prevent missteps.
Key Takeaways: Using EM Heat Wisely
Emergency heat is valuable for homes with heat pumps, but its purpose is specific. Use it only when your heat pump can't maintain adequate warmth, such as during severe weather or equipment malfunctions. Understanding what emergency heat is on a thermostat and how it impacts energy consumption can help you optimize your system and keep costs under control.
Maintaining your heat pump and ensuring proper insulation are proactive steps to minimize reliance on EM heat. When in doubt, consult with a professional from MR. HVAC to ensure your system is running efficiently and your home remains comfortable, even in the harshest conditions.
Need Help with Your Heating System?
Whether you're dealing with a malfunctioning heat pump or want advice on improving energy efficiency, our team of experts at MR. HVAC is here to help. Contact us today to schedule a consultation and learn more about optimizing your home's heating system.