WEBB CITY, Mo. (KSNF) — When dangerously cold weather is in the forecast, you’ll definitely be flicking on the thermostat. But is there another setting, “EM heat,” that you should be activating?
Heating issues keep those in the HVAC business busy during an arctic blast. A majority of calls are related to the need to manually turn on emergency, or “EM” heat, said Beau Rickman, co-owner of DR Mechanical, LLC in Webb City, Missouri.
“A lot of our service calls over the last few days have been related to the emergency heat or auxiliary heat setting,” said Rickman.
According to Rickman, emergency heat is a setting that controls your home’s backup heating system. It’s a secondary heating mode found on some, but not all, thermostats, particularly those used in heat pump systems.
In normal conditions, your heat pump is the primary worker. But in below-freezing temperatures, or when a unit’s heat pump malfunctions, this is where the EM heat setting kicks in.
“In general, people usually don’t have to activate emergency heat on their thermostat,” Rickamn Rickman explained. The emergency setting will usually take over automatically.
In fact, switching over to emergency heat manually can have some downsides.
“When you turn on your EM heat, you’re telling your heating system to stop using your heat pump and only use this supplemental source,” explained Valley Service, a North Dakota HVAC company, in a 2021 post.
“Now, instead of working with your main heat pump, your backup is working solo,” the post continued. “This is way less efficient than your primary heating system, so you should only use it in real emergencies unless you want to pay exorbitant heating bills.”
If you’re unsure when to use emergency heat, look to the setting’s name for inspiration: It should only be for emergencies, Rickman said.
You can turn on emergency heat while you wait for a service technician to come take a look, or while you wait for your heat pump to defrost.
“When it’s as cold as we’ve seen it get over the last few days, with temperatures near zero, and you’re just turning on the heat on your thermostat, you’re likely not going to reach the desired temperature you have your unit set to. It’s just going to continuously run 24/7 until it starts to warm back up outside,” says Rickman. “This is the ideal time to go ahead and switch your thermostat from heat to emergency heat. When the outside temperature gets above 25 degrees (Fahrenheit), that’s when you should turn off emergency heat and go back to the normal heat setting, which uses that heat pump.”
If this option doesn’t solve your home heating needs, it’s recommended that you contact an HVAC repair specialist.
“If there is a problem with your HVAC and you let it go for any length of time, it can cost you a lot more in the long run, versus a regular service call,” said Rickman.
