Does Your Heater Smell Like It’s Burning? 4 Explanations Why
Spring just on the horizon means your heater is about to go dormant for a while. Hooray! But be forewarned: You’re likely to notice a burning smell once you turn it back on at the start of the next cold season. Why? The most likely explanation is the dust mites and dander that stick to the heat exchanger or heat strips inside.
“When your heater comes on, the mites and dander burn off,” says Lee Downing, owner of Aire Serv Memphis and Tipton County in Tennessee.
According to Downing, the smell should disappear after about 10 to 15 minutes. But if it lingers for much longer, there may be an issue that needs professional intervention.
Here are four other reasons why a burning smell might be coming from your heater.
1. Clogged air filter
If your air filter hasn’t been changed recently (it should be changed every three months or so), the burning smell could be a sign that the filter is clogged, according to Downing. When you turn it on, the dust particles on the filter are going to burn off, hence the odor.
2. Cracked heat exchanger
If your heat exchanger—the set of coils in a furnace that heat the air—is cracked, you may smell it burning or hear it cycling over and over.
This can be a dangerous problem, and it can be difficult to pinpoint.
“Even technicians can miss it,” says Mike Donley, president of Donley Plumbing and Air Conditioning in Phoenix.
He says the only way to really tell your heat exchanger is cracked is through a carbon monoxide detector.
Like all pieces of equipment, heat exchangers can crack over time after repeated use. Consider a tuneup if you’re worried your equipment might not be working. This is a serious repair though, so if you do find a crack, turn off the heater and call in a heating, ventilation, and air conditioner professional immediately.
3. Dusty backup heat strips
If it gets very, very cold, your heater may kick on the system’s backup heat strips to add an extra warmth to your home. Donley says they don’t come on very often, but if they come on and have dust on them you may smell some burning.
4. Dusty electric strip heaters
Strip heaters look like coils that attach to an air-conditioning system and heat the air coming out of the blower. Although not very common, dust on electric strip heaters can cause a burning smell.
What to do if the heater starts smoking
Shut off the heater immediately if you see smoke coming from it and a call a professional. Smoking could mean there’s an issue with the “windings” or wire coil in your motor. Donley says it could be a sign that the motor has burned out or that the furnace isn’t venting properly.