If you have a heat pump, you have probably noticed your thermostat has at least three settings: heat, cool, and emergency heat. Having two heat settings seems odd, but many people never bother to learn the difference between the two. Don’t make the mistake of thinking it doesn’t matter. Knowing when to use the emergency heat setting — and when not to — can have a huge impact on your monthly energy bills.

How Emergency Heat Works

While a furnace creates heat, a heat pump works by pulling heat from one place and transferring it to another. When your home needs to be warmer, it pulls heat from the outdoor air; when your home needs to be cooler, it pulls heat from your indoor air and sends it outside. This can be a very energy efficient system — except when it gets too cold outside. In places where the temperatures dips below 35 degrees Fahrenheit, a heat pump will need a backup source of heat. That’s where the emergency heat setting comes in.

When you switch your system to emergency heat, your heat pump’s backup will kick in as a substitute. For an all-electric heat pump, this will be a form of electric resistance heating, but other options include gas, oil, or hot water. Several high tech heat pump options are available, but the basic principles remain the same. Whatever source your heat pump uses, it’s the backup for a reason. It will be less efficient than your heat pump.

Using the Emergency Heat Setting

The emergency heat setting is meant to ensure your home stays warm even if your heat pump quits working. It is called “emergency” heat because it should only be used temporarily, in the case of an actual emergency. Use it when your heat pump, due to external damage or an internal malfunction, cannot provide heat. Be sure to call an HVAC professional as soon as you make the switch, so you can get your heat pump working again as soon as possible.

A Common Misconception

Manage Temperature

Manage Temperature

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The most common misconception about the emergency heat setting is that you need to use it when it’s cold outside. Fortunately for your budget, that isn’t true. The setting is only necessary when your heat pump isn’t working properly — regardless of the temperature.

You may hear the two heat settings referred to as “stages.” First stage heating, of course, is your heat pump operating solo. Second stage heating refers to emergency heat only. As you now know, your heat pump needs help when the temperature dips below 35 degrees Fahrenheit – but that doesn’t mean you need to select the emergency heat setting at that temperature. Your system can use both first-stage and second-stage heating simultaneously and will do so automatically. The emergency heat setting, on the other hand, forces your heat pump out of the equation.

Time is money, but in this case, so is knowledge. Now that you know what emergency heat is, how it works, and when to use it, you can avoid using it unnecessarily and enjoy lower energy bills as a result.