The difference between emergency heat and a heat pump is crucial for homeowners, especially during winter. Many Americans rely on heat pumps for efficient home heating, but understanding when and how emergency heat should be used can impact safety, comfort, and energy costs. This article explains the roles, advantages, and proper usage of both systems, helping you make informed decisions for your home.
What Is A Heat Pump?
A heat pump is a two-in-one HVAC system that provides both heating and cooling for residential and commercial spaces. Heat pumps extract heat from outside air—even in cold weather—and transfer it indoors. This process is energy efficient, making heat pumps a popular choice in various U.S. climates.
How Heat Pumps Work
In heating mode, the pump absorbs heat from the outdoor air using refrigerant. The system then compresses this heat and circulates it indoors, warming the home. In cooling mode, the process reverses, drawing heat from inside and releasing it outdoors.
Primary Benefits Of Heat Pumps
- Energy Efficiency: Uses less electricity than conventional systems by transferring instead of generating heat.
- All-Season Comfort: Functions as both a heater and air conditioner.
- Environmentally Friendly: Reduces greenhouse gas emissions compared to fuel-based systems.
- Lower Operating Costs: Especially effective in moderate climates.
What Is Emergency Heat?
Emergency Heat (sometimes marked as “EM HEAT” on thermostats) is a backup heating mode on heat pumps. It activates the system’s second-stage heat source—usually electric resistance coils or a gas/oil furnace—when the heat pump can’t adequately warm your home on its own.
How Emergency Heat Is Activated
Typically, emergency heat is turned on manually by switching your thermostat to the ‘EM HEAT’ setting. Some advanced systems can also activate it automatically if the main heat pump malfunctions or if outside temperatures drop so low that the pump isn’t effective.
When To Use Emergency Heat
- Heat Pump Malfunction: When the primary heat pump fails or needs urgent repairs.
- Extreme Cold: In rare weather events where the heat pump cannot draw enough heat from outside air to maintain comfort.
- Defrost Cycles: While the heat pump defrosts itself, emergency heat may maintain the indoor temperature.
Main Differences Between Heat Pump And Emergency Heat
| Feature | Heat Pump | Emergency Heat |
|---|---|---|
| Energy Source | Extracts heat from outdoors using refrigerant | Uses electric resistance coils or gas/oil furnace |
| Efficiency | Highly efficient, low energy use | Much less efficient, higher energy use |
| Cost To Operate | Lower, especially in normal operation | Significantly higher |
| Activation | Automatic, primary heating method | Manual or automatic as backup |
| Frequency Of Use | Daily, during heating and cooling seasons | Rarely—only during breakdowns or deep freezes |
How Does A Heat Pump’s Auxiliary Heat Differ From Emergency Heat?
Auxiliary heat is an automatic backup that supplements the heat pump when it can’t keep up with demand (for example, during a cold snap). Unlike emergency heat—which the user activates—auxiliary heat turns on automatically and runs alongside the heat pump. Both typically rely on the same electric resistance elements or furnace but are activated differently.
When Should You Switch To Emergency Heat?
Most HVAC experts recommend only switching to emergency heat if the heat pump is malfunctioning or during severe weather extremes. A few scenarios when you should consider emergency heat include:
- Your outdoor heat pump unit is covered in ice and not functioning.
- The system isn’t blowing warm air, despite running continuously.
- You’ve received a maintenance recommendation from an HVAC technician.
Using emergency heat unnecessarily for extended periods leads to rapid increases in energy bills and isn’t intended for long-term use.
Pros And Cons: Heat Pump Vs Emergency Heat
| System | Pros | Cons |
|---|---|---|
| Heat Pump |
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| Emergency Heat |
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Common Mistakes With Emergency Heat Settings
Many homeowners confuse when to use emergency heat, leading to unnecessary costs. A frequent misconception is that it should be used in any cold weather. However, as long as the heat pump is working and providing warmth—even if slower—there’s no need to manually switch to emergency heat.
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- Avoid using emergency heat as a supplement: It won’t boost comfort faster and will just ramp up costs.
- Check for thermostat errors: Accidentally leaving the setting on ‘EM HEAT’ can run up your bill quickly.
Controlling And Monitoring Your System
Most modern thermostats clearly display the ‘heat’, ‘auxiliary’, and ’emergency heat’ modes. Smart thermostats can even alert you when auxiliary or emergency systems engage. It’s recommended to check your system’s manual and get professional guidance on settings unique to your installation.
If your area is susceptible to power outages or severe storms, consider a backup generator to keep emergency systems operational when needed most.
Emergency Heat And Energy Consumption
Because emergency heat uses electric resistance coils or additional fuel, its efficiency is dramatically lower than a standard heat pump. For example, a heat pump might use only one-third the energy of emergency heat to produce the same amount of warmth. If used for a long period, monthly energy bills can double or triple.
| Heating Option | Relative Efficiency (COP) | Estimated Monthly Cost |
|---|---|---|
| Heat Pump (Normal) | 2.5-4.0 | Low |
| Emergency Heat | 1.0 | High |
Note: COP = Coefficient of Performance (higher is better)
Climate Considerations: Where Does Emergency Heat Matter Most?
In moderate climates (e.g., southern U.S.), heat pumps rarely require emergency heat because temperatures remain within efficient operating ranges. In Northeast or Midwest states, where winter temperatures can drop sharply, emergency heat is a critical backup but is still used sparingly.
High-efficiency or cold-climate heat pumps can operate in temperatures as low as -5°F, reducing the need for emergency backup except during extreme events or outages.
Upkeep And Maintenance For Peak Performance
Regular maintenance extends the life and efficiency of your heat pump and emergency systems.
- Seasonal Inspections: Have a professional technician check refrigerant, electrical components, and thermostat calibration twice a year.
- Clear Airflow: Keep outdoor units free of debris, snow, or ice buildup that could trigger emergency mode.
- Test Emergency Function: Occasionally verify emergency backup responds as expected, especially if storms or outages are common in your area.
Cost Comparisons: Heat Pump Vs Emergency Heat Over Time
On average, a heat pump can reduce heating costs by up to 50% compared to electric resistance heating—such as emergency heat. Over a single season, relying too heavily on emergency heat can lead to hundreds of extra dollars spent in electricity or fuel.
| Scenario | Heat Pump (Monthly Cost) | Emergency Heat (Monthly Cost) |
|---|---|---|
| Mild Winter (40°F average) | $120 | $300+ |
| Severe Cold Snap (Use Emergency Heat for 1 week) | $150 | $200+ |
| Full Emergency Use (System Failure, 4 weeks) | N/A | $400-$600 |
How To Identify And Troubleshoot Heat Pump Vs Emergency Heat Problems
Staying alert to system performance ensures reliable warmth and prevents unnecessary emergency heat use. Signs of trouble include:
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- Lack of warm air: If heat output drops in freezing weather, check if the heat pump is iced over or not running.
- Frequent use of emergency heat without extreme weather or a clear malfunction.
- Unusually high electric bills: Indicates emergency or auxiliary heat running longer than intended.
Immediate attention from a licensed HVAC technician is advised for persistent issues.
Tips To Minimize Emergency Heat Usage
- Maintain your heat pump regularly—keep filters, coils, and vents clean to optimize efficiency.
- Insulate your home—weatherproof doors, windows, and attics to retain heat, reducing the load on your system.
- Program your thermostat—avoid drastic temperature swings which can trigger auxiliary or emergency modes unnecessarily.
- Consider upgrading to a cold-climate heat pump with better low-temperature performance if you live in a colder region.
What Homeowners Need To Know Before Switching To Emergency Heat
Before using emergency heat, confirm that the main heat pump is not functional or is dangerously inefficient due to conditions like ice buildup or mechanical failure. Overuse without cause can significantly raise energy bills and increase wear on backup equipment.
Understanding your specific system—brand, capacity, and climate rating—helps make the best energy and comfort decisions.
Frequently Asked Questions About Emergency Heat And Heat Pumps
- Should emergency heat run all the time in winter? No. It’s only designed for short-term use if the heat pump can’t keep up or is damaged.
- Does running emergency heat hurt the system? No, but using it for extended periods increases wear and utility costs.
- Is auxiliary heat the same as emergency heat? Both use the same backup source, but auxiliary is automatic—emergency is manual and for emergencies only.
- Can I run both heat pump and emergency heat together? No, switching to EM HEAT disables the heat pump and runs only the backup stage.
The Bottom Line On Emergency Heat Vs Heat Pump Functionality
The primary difference between emergency heat and a heat pump is their function, efficiency, and cost. The heat pump is the workhorse for most of the year, providing efficient and eco-friendly warmth. Emergency heat is a crucial but costly safety net—best reserved for true emergencies. Understanding when and how to use both ensures absolute comfort, safety, and savings.