Em Heat vs Heat: Understanding Your Thermostat Settings

As the cold months approach, homeowners turn to their thermostats to maintain a comfortable indoor environment. However, the various settings on a thermostat can often be confusing, especially when it comes to understanding the difference …

As the cold months approach, homeowners turn to their thermostats to maintain a comfortable indoor environment. However, the various settings on a thermostat can often be confusing, especially when it comes to understanding the difference between “Em Heat” and “Heat” modes. Misunderstanding these settings can lead to inefficient energy use and higher utility bills. This article will delve into the specifics of “Em Heat” versus “Heat,” clarify the differences between the two, and provide guidance on how to use these settings effectively.

Understanding Em Heat

Em Heat, short for Emergency Heat, is a setting found on many dual-fuel and heat pump systems. It is designed to be used as a backup heating option when the primary heat source, such as a heat pump, fails or is unable to efficiently heat your home. This mode taps into a secondary heat source, often electrical resistance heating, which can be more expensive to operate. Essentially, it’s your system’s way of saying, “In case of emergency, break the glass” and switch to the backup.

In Em Heat mode, the secondary heating system takes over entirely, bypassing the heat pump. This is crucial in extreme weather conditions where the heat pump alone may not suffice. However, since secondary systems like electric resistance heating are less efficient, they should only be used temporarily.

What is Standard Heat Mode?

Standard Heat mode, often simply labeled as “Heat” on your thermostat, uses the primary heating source, typically a heat pump in moderate climates or a furnace in colder climates. Heat pumps work by transferring heat from the outside air into your home, making them highly efficient under normal conditions. They can operate effectively in temperatures as low as around 30-35 degrees Fahrenheit.

In colder climates, homes may rely on a furnace that burns natural gas, propane, or oil to generate heat. Unlike the Em Heat mode, which relies on electric resistance heating, these systems can continue to function efficiently even as temperatures plunge. The key takeaway is that standard “Heat” mode leverages your primary heating source, which is more energy-efficient and cost-effective under typical circumstances.

When to Use Em Heat Mode

Em Heat mode should be used sparingly and only in specific situations. One primary scenario for using Em Heat is when your heat pump is malfunctioning. You might notice that your home isn’t warming up as it should be, or the heat pump is making unusual noises. In such cases, switching to Em Heat ensures your home remains warm while you schedule a professional repair.

Another scenario involves extremely low outdoor temperatures that make it difficult for the heat pump to extract heat from the air efficiently. Heat pumps generally struggle when temperatures dip below freezing. During these times, activating Em Heat can temporarily provide the extra warmth needed. However, because Em Heat is less energy-efficient, it’s advisable to return to the standard Heat mode as soon as conditions allow.

Energy Efficiency Considerations

One of the most significant distinctions between Em Heat and Heat modes is the impact on energy consumption. Heat pumps are designed to be highly efficient and can produce up to three times more heat energy than the electrical energy they consume. This efficiency drops significantly when switching to Em Heat mode, which relies on electric resistance heating. Electric resistance heating can be as much as three times more expensive in terms of energy usage compared to the heat pump.

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Given this stark difference, it’s crucial to use Em Heat mode only when absolutely necessary. Prolonged use of Em Heat can lead to spiked utility bills and increased wear and tear on your backup heating system. Therefore, switching back to standard Heat mode as soon as conditions improve is advisable to maintain energy efficiency and control costs.

Common Misconceptions

There are several misconceptions surrounding the use of Em Heat and Heat modes that can lead to inefficient heating practices. One common misunderstanding is that Em Heat will warm the home faster than standard Heat mode. While Em Heat can deliver warmth quickly, it does so at a higher energy cost. Another misconception is that Em Heat should be used whenever the temperature drops significantly. In reality, heat pumps are designed to operate efficiently even in lower temperatures, and switching to Em Heat prematurely can needlessly increase energy consumption.

Another frequent misconception is that “Em Heat” is the same as “Aux Heat,” or Auxiliary Heat. Although these terms might be used interchangeably, their function slightly differs. Auxiliary Heat often activates automatically when the heat pump can’t keep up with the heating demand. In contrast, Em Heat is a manual setting that forces the system to bypass the heat pump entirely.

Comparing Em Heat and Regular Heat

When comparing Em Heat versus Heat, it’s essential to recognize that each serves a specific purpose and is designed to operate under different conditions. Your heat pump, functioning in standard Heat mode, is optimized for energy efficiency and cost-effectiveness. It extracts heat from the surrounding air, which means it consumes less electricity while delivering a comfortable home temperature.

On the other hand, Em Heat mode should be considered a last resort, designed for emergency situations or extreme weather conditions where your heat pump cannot effectively perform. Although it delivers warm air quickly, it does so at a significantly higher cost due to its reliance on electric resistance heating. Therefore, your thermostat should ideally remain in standard Heat mode unless specific conditions necessitate the switch to Em Heat.

Tips for Optimal Thermostat Settings

To optimize your thermostat settings for both energy efficiency and comfort, follow these guidelines:

  • Regular Maintenance: Ensure your heating system, including your heat pump and backup heating source, undergoes regular maintenance. This can prevent unexpected breakdowns that would require the use of Em Heat.
  • Temperature Settings: Set your thermostat to the recommended temperature settings for winter. Generally, keeping your home at around 68 degrees Fahrenheit when you’re home, and lowering it slightly when you’re away can save on energy costs.
  • Use Programmable Thermostats: Invest in a programmable or smart thermostat that automatically adjusts the temperature based on your schedule. This helps in maintaining optimal settings without manual adjustments.
  • Monitor Energy Usage: Keep an eye on your energy bills and usage patterns to identify any significant changes that might indicate a malfunctioning heat pump or an over-reliance on Em Heat.
  • Professional Inspection: Consider having your system inspected by a professional, especially before the onset of winter, to ensure everything is in proper working order.
  • Manual Overrides: Avoid frequent manual overrides of your thermostat settings. Let your system operate as per its programmed settings to maintain efficiency.
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By understanding the distinct roles of Em Heat and Heat settings and using your thermostat effectively, you can ensure a warm, comfortable, and energy-efficient home throughout the winter months.

Understanding Em Heat Mode

**Emergency Heat (Em Heat)**, often labeled as “auxiliary heat” on your thermostat, is a backup heating system for your home. It comes into play mainly when your primary heating source, like a heat pump, isn’t sufficient to maintain your desired indoor temperature. Let’s delve deep into how Em Heat works, its significance, and when it’s most appropriate to use it.

In most residential settings, a heat pump is the primary equipment for heating and cooling. A heat pump works by extracting outdoor heat and bringing it indoors during winter and acts in reverse to cool down your home in summer. However, when temperatures drop significantly, a heat pump may struggle to maintain the warmth inside, given the minimal heat available in the frigid outdoor air. This is where Em Heat kicks in.

**How Em Heat Works**

Em Heat operates using electric resistance coils or a gas furnace—systems capable of generating more heat independently of the outdoor air temperature. These methods are typically more energy-intense and, therefore, more expensive to run than a heat pump. However, they offer a reliable backup when the heat pump can’t keep up. It’s crucial to understand that Em Heat is not meant for long-term use but rather as an emergency solution when your heat pump fails or during extraordinarily cold weather.

**Activating Em Heat**

Moreover, Em Heat typically requires manual activation on most thermostats. Homeowners should consult their user manuals or thermostat manufacturers to ensure proper understanding and usage. Improper usage can lead to inflated utility bills and unnecessary wear and tear on the heating system.


In summary, Em Heat is a vital feature of many home heating systems, ensuring your home remains warm even in the harshest weather conditions. However, conscious and informed usage is critical to manage costs and maintain system longevity.

When to Use Standard Heat Mode

**Standard Heat Mode** on your thermostat is the go-to setting for everyday heating needs. It leverages your primary heating system, usually a heat pump or a furnace, to maintain comfortable indoor temperatures. Understanding when and how to use this mode can significantly impact your home’s energy efficiency and your utility bills.

**Operation in Standard Heat Mode**

Your primary heating system, in Standard Heat Mode, operates by regulating the temperature based on the setpoint you determine on the thermostat. Unlike Em Heat, which acts as a supplemental resource, Standard Heat is your primary source of warmth during colder months. The efficiency of this mode largely depends on the type of heating equipment your home utilizes.

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**Heat Pumps and Standard Heat Mode**

For homes with heat pumps, Standard Heat Mode is highly efficient during moderately cold weather. Heat pumps are designed to move heat rather than generating it, making them cost-effective until the outdoor temperature dips too low for the heat pump to extract adequate warmth from the outside air. It’s generally advisable to keep your thermostat in Standard Heat Mode whenever the outdoor temperature is above the system’s balance point, allowing the heat pump to operate within its efficient range.

**Furnaces and Standard Heat Mode**

For homes with traditional furnaces, which may be powered by electricity, natural gas, or oil, Standard Heat Mode should be used consistently throughout the heating season. Furnaces are designed to generate significant heat output, making them reliable for maintaining comfort during extended cold periods. Ensuring regular maintenance and timely filter replacements can further optimize the furnace’s efficiency.

**Maximizing Efficiency**

Moreover, utilizing programmable thermostats with Standard Heat Mode can lead to enhanced energy savings. These devices allow you to set temperature schedules that align with your daily routines, such as lowering the temperature when you’re away from home or asleep, and raising it when you’re active at home.


To summarize, Standard Heat Mode is the backbone of your home’s heating strategy. Proper utilization, aligned with understanding your specific heating system’s capabilities and the ambient temperatures, can ensure a balance between comfort and energy efficiency. Employing programmable thermostats and regular system maintenance further bolsters this balance, keeping your home warm economically.


1. What is the difference between EM heat and regular heat on my thermostat?
Answer: EM heat (emergency heat) uses an alternative heat source, typically electric resistance heating, for situations when the main heat pump is not functioning, while regular heat primarily relies on the heat pump for heating.

2. When should I use the EM heat setting on my thermostat?
Answer: You should use the EM heat setting only when your heat pump is malfunctioning or unable to provide sufficient heat, such as during very cold weather or if the heat pump is undergoing repairs.

3. Is EM heat more expensive to operate than regular heat?
Answer: Yes, EM heat is generally more expensive to operate because it uses electric resistance heating, which consumes more energy compared to the heat pump.

4. How does EM heat work compared to regular heat?
Answer: EM heat activates the backup heating system, usually electric resistance heating, bypassing the heat pump, whereas regular heat utilizes the heat pump to transfer heat from outside to inside the home efficiently.

5. Can using EM heat cause any damage to my heating system?
Answer: Using EM heat as intended does not cause damage to the heating system; however, it should not be used continuously as it is a temporary solution designed for emergency situations and is less efficient.

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