When to Flip the Switch: A Guide to Using Your Heat Pump’s Emergency Heat

Understanding Your Heat Pump’s Emergency Heat Function

Heat pump emergency heat is a backup heating mode that bypasses your heat pump’s normal operation and relies entirely on a supplemental heat source—typically electric resistance coils—when your primary system fails or can’t keep up. It’s designed for emergencies only, not routine cold weather, and uses significantly more energy to run than your heat pump’s standard heating mode.

When to use emergency heat:

• Your outdoor heat pump unit has stopped working completely
• The unit is encased in thick ice that won’t clear after a defrost cycle
• Your system is blowing cold air despite running continuously
• You’re waiting for a repair technician in freezing weather
• The outdoor unit is making alarming noises or tripping breakers

When NOT to use emergency heat:

• During normal cold weather (even below freezing)
• When you see light frost on the outdoor coils
• During routine defrost cycles (these are automatic and normal)
• To warm your house faster after adjusting the thermostat

If you’re a homeowner in Puyallup, WA, you’ve probably spotted that “EM Heat” setting on your thermostat and wondered what it does. Many people assume it’s for extra warmth on cold days, but this can lead to a significant increase in energy usage. Emergency heat should only be activated when your heat pump genuinely can’t do its job.

For expert guidance on your heat pump system, explore our comprehensive Heat Pump services, or contact WestCoast Heating & Air for immediate assistance in Puyallup and surrounding areas.

Auxiliary Heat vs. Emergency Heat: Clearing the Confusion

When it comes to heating your home in Puyallup, WA, and the surrounding areas, our heat pump systems are incredibly efficient. They work by transferring heat from the outside air into your home during colder months, rather than generating heat by burning fuel. This “routing heat load” process makes them an energy-efficient alternative to traditional furnaces and air conditioners. However, like all complex systems, heat pumps have backup mechanisms to ensure your comfort, especially when temperatures drop or issues arise. This is where auxiliary heat and heat pump emergency heat come into play. Understanding the distinction between these two settings is crucial for maintaining both your comfort and your home’s energy efficiency.

Many homeowners find themselves confused by the terms “auxiliary heat” and “heat pump emergency heat,” often using them interchangeably. While both refer to a supplemental heating source, their activation and intended use are quite different. Auxiliary heat is typically an automatic function that works alongside your heat pump, while emergency heat is a manual override, a last resort when your primary heat pump system is struggling or has failed.

To help clear the confusion, let’s look at a quick comparison:

For a deeper dive into how your heat pump works and its many benefits, visit our Heat Pump page.

What is Auxiliary Heat?

Auxiliary heat, often labeled “Aux Heat” on your thermostat, is your heat pump’s automatic backup system. It kicks in when your heat pump alone can’t quite keep your home warm enough. This usually happens under a few conditions:

1. Large Temperature Difference: If your thermostat setting is significantly higher than the current indoor temperature (e.g., you turn the thermostat up by more than 2-3 degrees), your heat pump might need a boost to reach the new set point quickly.
2. Cold Outdoor Temperatures: As outside temperatures approach freezing or drop below 30-40 degrees Fahrenheit, heat pumps become less efficient at extracting heat from the air. In these conditions, your thermostat is often programmed to automatically engage auxiliary heat to help maintain the desired indoor temperature. Many thermostats are programmed to switch to auxiliary heat when the temperature drops to 25°F and below.
3. Defrost Cycle: Heat pumps occasionally enter a defrost cycle to melt ice buildup on the outdoor coil. During this time, the heat pump temporarily reverses its operation, which means it won’t be providing heat to your home. To prevent a noticeable drop in indoor temperature, the auxiliary heat automatically activates to keep you comfortable until the defrost cycle is complete. You might notice water or steam from the outdoor unit, the unit fan stopping, or a blinking light on some models during this process.

The auxiliary heat source is typically electric resistance heating coils, often located within your indoor air handler. While less efficient than your heat pump’s normal operation, it ensures your home stays warm when the heat pump needs a little help. It’s a normal and expected part of your heat pump system’s operation, designed to maintain comfort without you having to lift a finger.

What is the difference between auxiliary heat and heat pump emergency heat?

This is where many homeowners get confused, and it’s a critical distinction! While both auxiliary heat and heat pump emergency heat use the same backup heating source (usually electric resistance strips), the key difference lies in how and when they are activated, and what role your heat pump plays.

• Auxiliary Heat (Automatic and Supplemental): As we just discussed, auxiliary heat is automatic. Your thermostat senses that the heat pump needs assistance (due to extreme cold, a large temperature change, or a defrost cycle) and automatically turns on the auxiliary heat strips in conjunction with the heat pump. The heat pump continues to run, and the auxiliary heat provides supplemental warmth. It’s like a heat pump’s trusty sidekick, stepping in to lend a hand when needed.
• Emergency Heat (Manual and Primary): Heat pump emergency heat, on the other hand, is entirely manual. When you select “EM Heat” or “Emergency Heat” on your thermostat, you are effectively telling your heat pump to shut down its outdoor compressor unit completely. The backup heating system (those same electric heat strips, or a fossil fuel furnace in dual-fuel systems) then becomes the sole source of heat for your home. It’s not supplementing; it’s replacing. This mode is intended for situations where your heat pump is malfunctioning, broken, or operating inefficiently, and you need a temporary heat source to keep your home warm until repairs can be made.

Think of it this way: Auxiliary heat is like adding a warm blanket when you’re a little chilly (heat pump is still working). Emergency heat is like turning on a space heater because your main furnace broke down (heat pump is off). One works with your heat pump, the other works instead of it. Using emergency heat means you are relying entirely on the least efficient method of heating your home that your system offers.

When to Manually Activate Your Heat Pump Emergency Heat

Activating your heat pump emergency heat should always be a deliberate decision, not a casual one. It’s there for true emergencies, to provide warmth when your primary heat pump system is unable to. Our goal at WestCoast Heating & Air is to educate our customers in Puyallup, Tacoma, and surrounding areas so you know exactly when to flip that switch, and more importantly, when not to. When used correctly, emergency heat can protect your system from further damage and ensure your family stays safe and warm until our technicians can arrive.

Emergency heat is a temporary solution. If you find yourself needing to use it, it’s a clear signal that your heat pump requires professional attention. We’re here to help diagnose and resolve any issues. To understand more about common problems your heat pump might face, you can explore our guide on How to Identify Heat Pump Problems in Puyallup.

What are the signs I need to use my heat pump emergency heat?

Knowing when to use heat pump emergency heat is key to preventing discomfort and avoiding unnecessary energy use. Here are the clear triggers that indicate it’s time to manually activate this setting:

• Mechanical Failure or Outdoor Unit Not Running: If your outdoor heat pump unit has completely stopped working, is making unusual noises (like grinding or buzzing), or repeatedly tripping its circuit breaker, your primary heating source is compromised. In such cases, emergency heat is necessary to maintain warmth.
• Severe Ice Buildup Blocking the Outdoor Unit: While some light frost is normal and handled by the defrost cycle, if your outdoor unit is completely encased in thick ice that doesn’t melt after a defrost cycle, or if it’s struggling to clear, using emergency heat can prevent damage to the compressor. Turn off the outdoor unit and use emergency heat until the ice melts or a technician can safely clear it.
• Blowing Cold Air Consistently: If your heat pump is running continuously but consistently blowing cold or lukewarm air, it’s a sign that it’s not effectively extracting or transferring heat. This could be due to a refrigerant leak, a failing compressor, or other significant issues. While you wait for us to diagnose the problem, emergency heat will keep your home warm. For more on specific issues like this, check out our insights on How to Identify a Leaking Heat Pump in Waller. (Though this article focuses on Waller, WA, the principles of identifying a leaking heat pump apply to all our service areas, including Puyallup and Tacoma.)
• Awaiting Professional Repair in Freezing Weather: If your heat pump has a known malfunction and you’re waiting for one of our technicians to arrive, especially during freezing temperatures, activating emergency heat is appropriate to prevent pipes from freezing and to keep your family comfortable.

If your heat pump is genuinely broken, ineffective, or at risk of damage, and you need immediate heat, that’s when you flip the switch to emergency mode.

When should I NOT use emergency heat?

Just as important as knowing when to use heat pump emergency heat is understanding when not to. Misusing this setting can lead to a significant increase in energy consumption and put unnecessary strain on your backup system.

Here are situations where you should avoid using emergency heat:

• Mild Cold Snaps or Routine Cold Weather: Many people mistakenly believe they should switch to EM Heat when temperatures drop below freezing. However, modern heat pumps, especially cold-climate models, are designed to operate efficiently even in very cold temperatures, sometimes well below 0°F. Your system’s auxiliary heat is designed to supplement in these conditions automatically. The old “rule of thumb” to switch to emergency heat below 30°F or 25°F is largely outdated for modern, high-efficiency heat pumps.
• Normal Defrost Cycles: As mentioned, heat pumps automatically enter a defrost cycle to melt ice from the outdoor coil. This is a normal operation, and your auxiliary heat will automatically engage to maintain comfort indoors. You do not need to manually activate emergency heat during a defrost cycle.
• Small Temperature Setbacks: If you use programmed setbacks on your thermostat (e.g., lowering the temperature at night or when you’re away) and your home takes a little longer to warm up, resist the urge to switch to emergency heat. This is normal system behavior, and your heat pump, possibly with auxiliary heat, will recover the temperature efficiently. Using emergency heat to speed up a minor temperature recovery is very energy-intensive.
• To Warm the House Faster: Emergency heat often delivers a powerful blast of warmth, which can be tempting if you’re trying to quickly warm a chilly house. However, it does so by using significantly more energy. Let your heat pump and its automatic auxiliary heat do their job. They are far more energy-efficient for everyday heating.

If you’re ever unsure why your heat pump isn’t performing as expected, or if you suspect an issue, we recommend consulting our interactive troubleshooter for some initial checks. For anything beyond simple troubleshooting, it’s always best to call our professionals.

The Implications of Using Emergency Heat

While heat pump emergency heat is a valuable feature for critical situations, it comes with significant implications, primarily concerning energy consumption and the strain on your heating system. It’s vital for homeowners in Puyallup, Tacoma, and our other service areas to understand these drawbacks to make informed decisions.

High Energy Consumption

The most immediate and impactful implication of using emergency heat is the dramatic increase in your energy consumption. Why? Because emergency heat typically relies on electric resistance heating strips. Unlike a heat pump, which transfers heat (making it highly efficient), electric resistance heating generates heat directly from electricity. This is a far less efficient process.

To put it in perspective, running your system on emergency heat can use several times more energy than running it in its standard mode. This is because in normal operation, electricity is used to move heat, while in emergency mode, electricity is used to create heat directly—a much less energy-efficient process.

This stark difference in efficiency means that using emergency heat for extended periods, or when it’s not truly necessary, will lead to a substantial increase in energy usage.

System Strain and Inefficiency

Beyond the high energy use, relying on emergency heat can also affect your overall HVAC system. While your backup heating elements are designed to provide heat, they are not intended for continuous, long-term use as the primary heating source.

• Increased Wear and Tear: Frequent or prolonged use of electric heat strips can lead to increased wear and tear on these components, potentially shortening their lifespan.
• Inefficiency: The very nature of emergency heat is less efficient. Over-reliance on it negates the efficiency gains you achieve from having a heat pump in the first place.
• Protection of the Heat Pump: Ironically, using emergency heat when your heat pump is malfunctioning can protect the heat pump itself from further damage by allowing it to remain off until repairs are completed. However, using it when the heat pump is capable of running, even if less efficiently, is counterproductive.

To maximize your heat pump’s efficiency and avoid unnecessary reliance on emergency heat, consider the Advantages of Upgrading to a High-Efficiency Heat Pump. Modern systems are designed to handle colder temperatures more effectively, reducing the need for auxiliary or emergency heat.

What to Do After Activating Emergency Heat

If you’ve had to activate your heat pump emergency heat, it means your primary heat pump system likely has an issue that needs attention. This isn’t a “set it and forget it” solution; it’s a temporary measure. Here’s what you should do after flipping that switch:

1. Schedule a Professional Inspection Immediately: This is the most crucial step. As soon as you activate emergency heat, contact WestCoast Heating & Air to schedule a diagnostic appointment. Our experienced technicians in Puyallup, Tacoma, and surrounding communities can identify the root cause of your heat pump’s malfunction and perform the necessary repairs. Delaying this can lead to prolonged reliance on energy-intensive emergency heat or potentially worsen the underlying problem.
2. Turn Off EM Heat After Repair: Once our technician has repaired your heat pump and confirmed it’s functioning correctly, remember to switch your thermostat back to its normal “Heat” mode. Leaving it on emergency heat unnecessarily will continue to result in high energy consumption.
3. Check Air Filters: While waiting for service, or after repairs, it’s always a good practice to check your air filters. A clogged filter can restrict airflow, making your heat pump work harder and potentially contributing to system inefficiencies or even failures. A clean filter ensures optimal performance for both your heat pump and your backup system.
4. Ensure System is Reset: After repairs, our technician will typically ensure your system is properly reset. If you notice any lingering issues or warning lights after your heat pump is supposedly fixed, don’t hesitate to give us a call.

Regular maintenance is key to preventing situations that necessitate emergency heat. We recommend scheduling annual tune-ups for your HVAC system. Learn more about the importance of routine care on our page: How Often Should You Schedule an HVAC Tune-Up?. You can also prepare your system for the colder months by following the advice in our Fall HVAC Maintenance Prepare Your Home for the Autumn Cold guide.

Frequently Asked Questions about Emergency Heat

We often get questions from homeowners in Puyallup, Sumner, Tacoma, and our other service areas about their heating systems, especially concerning that mysterious “EM Heat” setting. It’s completely normal to have questions about something so critical to your home comfort! Let’s address some of the most common inquiries we receive regarding heat pump emergency heat.

For more detailed information, you can always refer to resources like When Should You Use the Emergency Heat on Your Heat Pump System?. And of course, our team at WestCoast Heating & Air is just a phone call away if you need personalized advice or service. Contact Us anytime.

How long can I run my system on emergency heat?

You can run your system on heat pump emergency heat continuously, 24 hours a day. However, it’s crucial to understand that it is designed for temporary use only. It should only be active until your primary heat pump system is repaired or until the conditions that necessitated its use (like extreme ice buildup) have passed.

There are several reasons why running emergency heat for extended periods is not advisable:

• High Energy Usage: As discussed, emergency heat consumes significantly more electricity than your heat pump’s normal operation. Prolonged use will result in a significant increase in your home’s energy consumption.
• Potential for System Strain: While the backup heating elements are robust, they are not designed to be the sole, long-term heating source for your home. Continuous operation can lead to increased wear and tear on these components, potentially shortening their lifespan or leading to premature failure.
• Inefficiency: It’s the least efficient way to heat your home with a heat pump system. Its primary purpose is to provide warmth when no other option is available, not to be a cost-effective heating solution.

So, while it can run constantly, it should only run for the shortest duration necessary to maintain comfort and prevent issues like frozen pipes until our professionals can restore your heat pump’s normal function.

Can using emergency heat void my heat pump’s warranty?

This is a great question, and the answer typically depends on the specific circumstances and your manufacturer’s warranty terms. Generally, using heat pump emergency heat when it is truly needed due to a legitimate malfunction or extreme conditions will not void your warranty. In fact, in some cases, using it can help protect the more expensive components of your heat pump (like the compressor) from damage if they are struggling or failing.

However, misusing emergency heat – for example, running it unnecessarily for extended periods without a genuine heat pump malfunction, or using it as a primary heating source out of convenience – could potentially be seen as operating the system outside of its intended design parameters. While it’s rare for a warranty to be voided solely for activating emergency heat, it’s always best practice to:

• Consult Your Manufacturer’s Guidelines: Your heat pump’s manual will have the most accurate information regarding warranty stipulations.
• Use It Judiciously: Reserve emergency heat for genuine emergencies.
• Document Issues: If your heat pump malfunctions, note the date and time, and contact us for professional service. This creates a record of a legitimate issue.

Our advice is always to use emergency heat as intended – as a temporary backup during a system failure. If you have concerns about your warranty, our team can help you understand your system’s specific requirements.

How do I know if my heat pump has an emergency heat feature?

Most heat pump systems installed in our service areas, especially those in climates like Puyallup, Tacoma, or Sumner where temperatures can drop significantly, will have an emergency heat feature. However, it’s always good to confirm. Here’s how you can tell:

• Thermostat Labels: The easiest way to check is to look at your thermostat. You’ll typically find a switch, button, or digital setting labeled “EM Heat,” “Emergency Heat,” or sometimes just “Emergency.” If your thermostat has this option, your system is almost certainly equipped for it.
• System Manual: Your heat pump system’s owner’s manual will provide detailed information about all its features, including whether it has an emergency heat option and how to operate it.
• Professional Confirmation: If you’re still unsure, the most reliable way to confirm is to ask one of our qualified HVAC technicians. During a routine maintenance visit, we can inspect your system and tell you definitively if it has emergency heat and how it’s configured. We can also verify that the backup heating elements (like electric heat strips in your air handler) are present and functional. While a thermostat might show an “EM Heat” option, the actual backup heating strips need to be installed in your air handler for the feature to truly work.

Conclusion: Trust the Experts with Your Home Comfort

Understanding your heat pump system, particularly the nuanced roles of auxiliary heat and heat pump emergency heat, is paramount for maintaining comfort and managing energy consumption in your Puyallup, WA, home. We’ve learned that while auxiliary heat is your heat pump’s automatic helper in colder conditions or during defrost cycles, emergency heat is a manual, temporary solution reserved for genuine system malfunctions or extreme circumstances. Misusing emergency heat can lead to a significant increase in energy consumption and undue stress on your backup system.

Our commitment at WestCoast Heating & Air is to provide homeowners in University Place, Tumwater, Tacoma, Sumner, Steilacoom, Spanaway, SeaTac, Roy, Puyallup, and Orting with not just top-quality products and service, but also the knowledge to make informed decisions about their home comfort. With over 20 years of local experience, we specialize in customized system design and comprehensive customer education, ensuring your HVAC system operates efficiently and reliably.

By adhering to proper maintenance schedules, understanding when to use each setting, and avoiding unnecessary reliance on emergency heat, you can extend the life of your system and maintain energy efficiency. If you ever find yourself needing to activate heat pump emergency heat, it’s a clear signal to call in the professionals. Our team is ready to diagnose and repair any issues, restoring your heat pump to its optimal performance.

For comprehensive care and to ensure your Heat Pump is ready for any season, schedule a professional service with WestCoast Heating & Air. Don’t hesitate to Contact Us for expert advice or service requests in your area. We’re here to keep your home comfortable, efficiently, and safely.