Many thermostats come with an “Emergency Heat” setting. Whether your home has a combined HVAC system of a simple heat pump thermostat, you may not fully know what the Emergency Heat switch really is. We’ve seen many homeowners who opt to turn on the Emergency Heat whenever they want to give their home a heat boost. But that’s not always a wise decision. Now that the weather is cold, we’ve decided to clear up some of the misconceptions about Emergency Heat switches.

Many people think that heat pumps don’t work in extreme cold weather and they are supposed to use the Emergency Heat when it gets really frigid outside. Not the case! Most heat pumps in cool climates include a supplemental (aka “Emergency”) heating source that exists to assist the main system. Usually it is some type of all-electric heater sometimes referred to as the “second-stage” or “back-up” heating. Different systems and thermostats have different ways of determining when the second-stage heat comes on to assist the heat pump, but it is always automatic. The two stages will work together in the colder months so it is not necessary to switch your thermostat to Emergency Heat for the second stage to do its job.

When you do switch on the Emergency Heat, your HVAC system will use your supplemental heat by itself and shut down your more powerful first-stage heat pump. The supplemental heater may act faster and seem hotter than your main home heat source in the dead of winter, but it often can’t distribute heat as far or as evenly as the first-stage pump. Not to mention the massive amount of energy it will use if it’s an all-electric piece. The efficiency of the whole heating system is often many times more efficient than just the emergency heater. A red indicator light will go on and stay on until you stop using the Emergency Heat. This just lets you know when you are in emergency mode.  If your thermostat is not set to emergency heat and the light is on that usually indicates a problem with your heat pump.

As the name implies, Emergency Heat should only really be used in emergency situations when there is something wrong with first-stage heating. If you notice your house is cold and isn’t heating properly that could be a good time to switch to Emergency Heat and call for heater repair service. During the winter and in the warmer autumn months that lead up to it, you should try to make it a habit of looking at your outdoor heat pump. If you don’t know what to look for exactly, get the help of an air care professional. When heat pump problems are caught early on, they can often be righted with a minor repair rather than an expensive replacement process.