Cost of Energy Bills in AUX Heat Mode Because your heat pump and backup heat source work together, AUX mode consumes more energy. This leads to increased energy bills — your costs may be up to 50% higher when the device is using AUX heat.
Auxiliary heat strips supplement the heat pump and produce warm air to quickly heat your home. Those heat strips use substantially more energy and will increase your electric bill.
This shows natural gas is the cheapest type of heating to run and heating oil is the most expensive way to heat a home.
When the outdoor temps are between 35 and 40 degrees or colder, the heat pump may struggle to pull enough warmth from the air outside. This is where the heat pump auxiliary heat system comes in. The auxiliary system often uses electricity as its main source of power, but auxiliary systems can also use gas or oil.
If you have a heat pump, this is normal. The pump and air handler will run constantly when it's this cold unless you lock it out (don't recommend). The aux heat will kick on & off as needed to help your heat pump maintain your set point.
Depending on your heat pump system, auxiliary and emergency heat can cost about 2-5 times as much as running normal heat. Though it's necessary for a heat pump to operate with auxiliary heat at times, you can take steps to reduce how frequently it's automatically used. Keep your thermostat set at 68 degrees.
Troubleshooting heat pump aux heat issues
Unless it's very cold outside, the aux heat system shouldn't need to run too long. If it's above 40 degrees and your thermostat shows AUX HEAT for more than an hour or two, you might want to investigate.
Typically, auxiliary heat on thermostat should not stay on for longer than 30 min to an hour. So, if it stays on unusually long, you have a problem that will raise your electric bill.
While it comes from the same source as emergency heat, it actually is designed to support your heat pump to become more efficient as opposed to taking over completely. So it doesn't cost as much to run as your emergency heat.
Some heat pumps are designed operate independently without back up heating, while others are designed to use a back up heating system. Whether or not you need a backup heat source for your heat pump will depend on the type of heat pump you purchase, your climate zone, and the design and efficiency of your home.
In colder climates, the heat pump works harder to extract heat from the outside air, leading to higher energy use and increased bills. Similarly, in hotter climates, the cooling function of the heat pump will be used more frequently, resulting in higher electricity consumption.
Because your heat pump and backup heat source work together, AUX mode consumes more energy. This leads to increased energy bills — your costs may be up to 50% higher when the device is using AUX heat.
Auixiliary Heat will turn on automatically when heat can no longer efficiently transfer heat from the outside air to heat pump. This is when the outside is around 35-40 degrees and the indoor temperature is around three degrees cooler than the thermostat setting.
Turning on your heat pump for the first time (or your auxiliary heat coming on for the first time) will burn those particles off the coils, and that's what you smell. If after a couple of cycles, or definitely after the first day, that smell is still hanging around, you should call your HVAC technician to check it out.
The auxiliary heat setting on an HVAC unit usually turns on when you need heat fast. If this secondary heating system is constantly running, it may mean that the weather outside is very cold or that the thermostat is set higher than normal. It's also possible that a part of the heat pump is malfunctioning.
This heating method works incredibly efficiently until the outdoor temperature reaches about 35 degrees. At this point, the heat pump has difficulty extracting enough heat from outside to keep up with the thermostat setting. This is when many people assume it's time for switching their heat pump to emergency heat.
It's normal for your heat pump to run fairly constantly in the winter time. With low temperatures, your pump will be working nonstop for hours to ensure your home stays warm. But if your heat pump is working overtime in the spring or summer when temperatures are milder, you may have an issue!
The auxiliary heat assists the heat pump in achieving the thermostat's set temperature. Once the set temperature is met, the heat pump and the auxiliary heat both shut off. If your Auxiliary heat is running for an extended time, you should call for a heating repair.
The heat pump itself might have a problem that needs to be addressed as soon as possible. There could be a refrigerant leak, or the reverse valve is malfunctioning. Either issue prevents the unit from blowing warm air in heating mode, requiring immediate attention from an HVAC technician.
Your aux heat indicator signifies that your heat pump needs some extra help reaching your desired temperature setting. When you see aux heat on the thermostat, you'll know your heat pump is attempting to energize the auxiliary heat strip inside your secondary heating source.
However, auxiliary heat mode can use more energy than regular heat mode, and frequent or prolonged use can increase your utility bills. Additionally, if it comes on often during mild weather, it could indicate an issue with your heat pump or thermostat that may need attention.
Running your heating system in EM heat mode will quickly drive up your energy costs. On average, emergency heating adds about $20 per day compared to using your heat pump in regular heat mode.