Heat strips may be a term you have heard somebody use when talking about a heat pump and/or when the outside temperatures begin to fall. Electric heat strips, emergency heat strips, and auxiliary heat strips are supplemental heat sources located inside the air handler of your HVAC system. If you have a split system, it’s located in your attic or under your home. If you have a packaged unit, it’s outside.

Advise Guy, Eric Gainey

An easy way to describe a heat pump is an air conditioner that can run in reverse. When in heat mode, it moves heat from outside to inside your home. As expected, when outside temperatures get extremely cold, there is less heat to extract out of the cold air and the heat pump may need help meeting the thermostat setting.

When this happens, your system will call for the heat strip(s) to come on. Depending on the type of system and size will determine the heat strip kilowatt (kW) amount and stages involved.

Think of these strips as wired elements you may find in an electric oven. These heat strips are a big part of why energy bills are higher in the winter months versus the summer. Unless you have an app or stare at the thermostat, a lot of times you will not know when they are running. The majority of the time, they will stage when it is coldest outside.

Even if you set your thermostat at the recommended setting of 68 degrees, the heat strips will still come on at times. When it is running in regular heat mode but has not changed the thermostat setting over a period of time, the heat strips will come on. Days that do not get out of the 30s or lower are guaranteed days for heat strips to run. A 20-plus degree difference between the outside and inside of your home is significant for a heat pump to keep up.

Heat pump thermostats will give you the option to turn on the heat strips manually and you need to avoid that if possible. It may show in your thermostat as emergency heat or auxiliary heat. The only time you want to turn on the heat strips manually is if the first stage of heating is broken.

When you manually engage emergency heat, it will bypass the outside condenser and work like an electric furnace. Run it in that mode and call an HVAC company to repair it.

The first stage is the heat pump stage where it pumps heat in from the outside to inside. Be mindful if you move the thermostat up more than 2-3 degrees, it will automatically stage in these strips. That is why we say set it and forget it. The heat strips also come on in defrost mode. When running in heat mode, the condenser will get colder because it’s transferring the heat around it into the home. Ice can begin to form on the condenser outside and once the outside condenser reaches a certain temperature, it should go into defrost mode.

At this point, it moves the hot refrigerant to the condenser to melt the ice. The heat strips come on so it does not offset the work it’s put in pumping heat into your home and so you don't feel the cold air coming in the home.

Remember, even if you don't touch the thermostat, the weather conditions outside will determine how much and how long the heat strips run. For more information on ways to save, please visit sremc.com or call us at 910.892.8071.