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What Is The Emergency Heat Switch On My Thermostat For And When Should I Use It?

cat cuddled up in home using emergency heat

So you’ve noticed it, the small “Emergency Heat” or “Em Heat” setting on your thermostat. What’s it for? Why would you need it? Should you turn it on when it gets really cold outside?

There are several important factors that come into play when figuring when to use emergency heat. If you’re confused about whether to use normal heat or em heat, read this guide!

How Does My Heat Pump Work?

While this obviously isn’t your main question, to understand your emergency heat setting, you have to first understand a little bit about your heat pump. These devices work to push heat from inside your home to the outside during the summer months and vice versa during the winter. This process helps keep your home at a comfortable, liveable temperature all year round.

As you may have guessed, however, when the outside temperature goes below 40 degrees, there’s not a lot of heat to pull in. To keep your home comfortable and livable, you need a supplementary source of heat, often referred to as auxiliary heat.

Much like the toaster you use for breakfast, heat pumps are built with an auxiliary heat strip. This heats up your home quite nicely! The only issue with them is that the heat strip guzzles energy and quickly drives up your electric bill, something that’s uneconomical and unwanted by most homeowners.

That’s why you often see heat pumps and furnaces paired together in homes to provide a sufficient, affordable supply of heat during the winter. The heat pump supplemental heat complements the work your furnace is doing. Both work together to provide a comfortable temperature at a reasonable cost all winter long.

So what does this have to do with your emergency heat setting on your thermostat?

What Is The Emergency Heat Setting?

A lot of people are under the impression that the emergency heat setting should be used when it gets cold outside. However, this assumption would be incorrect. The “em heat setting” is only supposed to be used in actual cases of emergency.

When you switch on your em heat setting, a red indicator light should appear and it will stay on until you stop using your emergency heat. This light is there to show you are in emergency mode.

Emergency mode stops the heat pump from working and forces your home to rely completely on the secondary source of heat, often a furnace. When you turn on your em heat setting, you’re essentially telling your heat pump to stop pulling warm air from outside and to rely entirely on your backup heating.

Why Is Using The Em Heat Setting All The Time A Bad Idea?

While your heat pump will gladly oblige, now you’re only using your gas or electric furnace to supply heating to your home. In most cases, this is far more expensive than using the two sources together. 

While your backup furnace is more efficient than the heat strip in your heat pump, it is far less efficient than your heat pump pulling in heat from outside and supplementing with furnace heat.

In short, the emergency heat setting allows you to use only your supplemental heat. Emergency heat is constantly using your backup supply of heat and not your main supply.

When Should I Use My Emergency Heat Setting?

As mentioned above, when to use emergency heat is only in the case of an emergency. A really cold day isn’t emergency enough. This setting is there to help you keep your home warm should your heat pump cease to operate properly.

If your heat pump malfunctions, appears to be damaged, or fails to provide sufficient heat, you should use your emergency heat. This setting allows your backup heater to fully supplement the heat in the home so as to keep it comfortable. This setting is only meant to be used for a short time until a professional heating and cooling technician can come to your home and repair your heat pump.

During the winter months, it’s a good idea to create a habit out of examining your outdoor heat pump. Look for signs of ice or snow build-up and be sure to keep it as clear of debris as possible. This will help your heat pump last longer since it won’t need to work as hard to pull in heat.

Heating Emergency? Trust Your Home To John C. Flood

You don’t need to turn on your emergency heat just because it’s gotten cold outside. Trust your heat pump to use the auxiliary heat in its own way to supply a sufficient amount of heat to your home.

If your heat pump is struggling to supply regular heat or if you haven’t yet gotten it inspected this season, then you should consider getting your heat pump inspected before the coldest months hit. In addition, if your emergency heat is not working, make sure to contact HVAC experts before you need to use the setting.

If you need to know when to use emergency heat don’t hesitate to reach out to our team of experts. To schedule your seasonal HVAC maintenance visit, call John C. Flood at (703) 752-1266 or schedule service online.