What Is Emergency Heat?

Broken Heat PumpIt’s right there on the thermostat, so it has to be important, but do you really understand the Emergency Heat setting? It has something to do with the heat pump outside, and you wish you’d asked about it when the unit enjoyed it’s annual tune-up. Before you turn the setting on out of curiosity, it’s a good idea to understand what it is, when you need it and what happens when you flip that switch.

Emergency Heat, What Is It?

Your heat pump is designed to operate efficiently within a broad range of winter temperatures as it pulls heat from the outside air to warm the house. When bitterly cold conditions don’t give it much to work with, the system automatically switches into Auxiliary Mode and kicks in a supplemental heat source. Depending on your home, this might be electric or gas, but it’s a backup mechanism that keeps the family warm until the heat pump can do its job again. The Emergency Heat setting bypasses this arrangement and fires up your supplemental heat with one switch. It’s important to note the word “emergency” in this equation, because turning it on shuts down the heat pump. It’s not a setting to turn on just because your feet are a little chilly.

When Do I Need to Use It?

The good news is you’ll rarely need to use the Emergency Heat setting. Like it’s name implies, this mode is intended for worst-case scenarios. The bad news is that scenario means your heat pump isn’t working. However, it’s easy to jump to the wrong conclusions about your unit’s performance during the winter. You might assume that there’s a problem because it seems to run constantly. This is normal, and the heat pump’s design allows it to run efficiently for extended cycles. It also operates a defrost mode that heats the outdoor coil to melt off accumulated ice and restore optimal airflow. This produces a white, steamy smoke that lasts for about 10 minutes, but it’s not a sign of unit failure. You only need to switch on the Emergency Heat setting when the heat pump stops working.

What Happens When I Use It?

Setting the thermostat to Emergency Heat tells the system to completely bypass the heat pump. This fires up the auxiliary part of the unit and keeps the house warm until you can get the system repaired. It cuts off signals to the heat pump so that the electric or gas components remain on. Your thermostat might have a red indicator light that makes certain you’re aware of the setting, and there might be a similar signal on the outside unit. The backup system provides plenty of heat, but its operation is expensive compared to the cost of a well-functioning heat pump. You’ll want to put in a call for repairs as soon as you realize there’s a problem.

While it’s great to have that Emergency Heat setting as a backup, a better plan involves yearly inspections to head off heat pump problems and make sure it’s in good shape for the winter. Before flipping that Emergency Heat setting, talk to the HVAC professionals at Max Mechanical Air Conditioning & Heating. We are the best backup for your backup system, so give us a call at the first sign of trouble. Your heat pump and your utility bills will thank you.

Call us at 817-459-4100 or contact us online to request a service call.


Image source by chanbliss

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Tim Shanks  /  March 17, 2014 at 4:59pm  /  Reply

Question? I have a Heat Pump where the indoor unit is located in the attic and we have run into a .03 asbestos issue with the loose insulation in the attic. When the emergency mode heat (or working regularly) is there a inside blower fan in the indoor unit pulling air from the attic and pushing it through the duct work. I have a wife with COPD and a 5 yr. old with Asthma?? Should I be concerned?? The only time that the attic would be disturbed is when a service call is made or an annual check up on the unit would be performed and I will let them know the possible hazard. Please help with your pro opinion on this matter.

Max Mechanical  /  January 10, 2017 at 5:34pm  /  Reply

Tim, I just now began getting notifications for this, I wish I’d gotten it 2 years ago when you posted it!
Anyway, no, the indoor fan does not pull air from the attic, it symbols circulates air from the house the same as it would in a/c or heat pump mode. However, the inside of the cabinet is insulated, It is possible for tiny fragments to be sucked int to the heat strips, however, this is normally not a major issue.. I would imagine you’ve already gotten the answer you need, but just in case I wanted to reply.
Max mechanical team

Laura  /  February 27, 2015 at 6:20pm  /  Reply

My landlord of three years in a large low income housing complex instructs everyone repeatedly by newsletters to ONLY use the emergency setting in the winter. While conducting this last quarterly inspection they actually turned it to this setting without telling me they had done it. Is this costing tenants more? How does using one or the other affect the water heater, if any? Thanks!

DEBBIE CRABTREE  /  November 22, 2016 at 5:36pm  /  Reply

I have an American Standard unit how do I change the temperature that the emergency heat will cut on?

Dawn Boddy  /  January 10, 2017 at 5:08pm  /  Reply

Two month ago we had our yearly checkup. All was well. We are selling our house and the hvac inspection says the heat strip failed because it wouldnt respond. I calked our regular company who said it passed with no problem. So i researched how it works and did my own test. I turned on emergency heat. Research says this bypasses heat pump and uses heat strip only. My thermostat is climbing. Is this a good indicator that the heat strips are in fact working?

Shannon Ritchie  /  November 28, 2018 at 9:48pm  /  Reply

I’m wondering how to turn my emergency heat on my unit is frozen . I’ve looked on the thermostat on wall can’t seem to figure it out. It shows it’s 62 in my house when it’s 30 outside

Max Mechanical  /  November 28, 2018 at 10:13pm  /  Reply

Hi shannon There should be a setting on your thermostat, often it says “em heat” what type of thermostat do you have?

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