Why Does My House Smell Bad When I Turn on the Heat?

Something customers wonder about this time of year is the odor that comes along with using a heating system after months of sitting idle. Let's get into it and understand what you're smelling when the heat is turned on this fall.

Crisp cool mornings and evenings, low humidity, and earlier sunsets mean one thing: fall is in the air. Even though we haven’t reached that flip of the seasonal calendar just yet, the welcomed cooler temperatures could have you thinking about turning on your home’s heating system. 

Something customers wonder about this time of year is the odor that comes along with using a heating system after months of sitting idle. Let’s get into it and understand what you’re smelling when the heat is turned on this fall.

Why Does My Heater Smell Like It's Burning?

You wouldn’t typically associate odor with your central heating system, but with that first use, it’s actually pretty common. In areas like Cleveland and other parts of the country that experience distinct seasonal temperature shifts, a central heat system is necessary to deal with the biting chill of winter. But for about half the year, temperatures are either mild or oppressively hot––you’re not thinking about the furnace in July! 

For all those months that the furnace sits, it collects normal, household dust. Even if you’re regularly cleaning around your furnace, dust can collect within the heating unit and throughout the ducts. When you start things up on that chilly evening or morning in autumn, the dust that’s accumulated does the inevitable: it burns. The smell of burning dust can then cycle through your ductwork. Thankfully the odor usually clears up on its own. If it doesn’t, here are some other causes to consider:

Trapped Debris: If the odor lingers after a few heat cycles and the burning smell can be isolated to one vent or room, there very well could be a misplaced toy or other item, or a piece of the heater itself that has become dislodged. 

What to Do? If the smell is localized to one room, you could turn off the unit and then carefully remove the vent cover. Look to see if any object is within reach and if so, remove it. If the debris appears to be part of the furnace it’s really best to give a heating technician a call first. And if there seems to be a buildup of dust, it might be a good idea to run a vacuum while the unit isn’t operating. A little DIY duct cleaning can go far to improve the health of your system.

System Leaks or Faulty Parts: If you’re noticing a distinctly “oily” smell when the furnace kicks on then your system could very well be leaking oil. There may also be a malfunctioning or dirty burner to blame. 

What to Do? Whatever the cause, it’s not great for your health or your heating system if an oily odor lingers. Your best bet here is to call in an HVAC specialist to evaluate the situation and suggest the best remedy. 

Gas Leaks: While propane and natural gas are naturally odorless, they’re also very dangerous if not contained. Methyl mercaptan is an organic compound that’s added to the gasses to help track down leaks. It has a recognizable “rotten egg” or “rotten cabbage” odor that should never emanate from a healthy HVAC system. If you smell this tell-tale stench then it is a clear sign that there is a gas leak somewhere. 

What to Do? Gas leaks are dangerous, and immediate action is vital. Shut off your furnace immediately and if the smell is pervading your home, get outside and away from the fumes. Then it’s best to call the fire department or gas company so they can pinpoint the leak. If the leak is within the furnace, an HVAC technician can handle the fix.

Electrical Short: If the odor coming from your furnace is less like dust burning and more metallic or plastic in nature, then you could be dealing with electrical issues. A short in the system’s wiring could cause the wire and its coating to burn, which will create a pungent, unmistakable odor.

What to Do? Electrical issues are serious and can cause fire or electric shock if you attempt to tackle this problem yourself. The best course of action is to shut off the unit immediately and call your HVAC technician to come and assess the situation.

Dirty Filter: If you’ve done some troubleshooting but haven’t found a root cause for the burning odor coming from your furnace, it’s worth checking the filters. Built up dust and debris can restrict airflow and cause the system to overcompensate in an attempt to force air through. That could put a strain on the entire system and end up causing preventable damage.

What to Do? Clearly, changing the filter is key. If your HVAC system requires an unusual size or quantity, the team at Fred’s Home Services is more than happy to track down the filter you need. Since the dirty filter may have strained your system’s mechanics, an annual inspection is an easy way to make sure that all parts are in good working order as you enter the colder months. Going forward, a maintenance program ensures that small problems never get out of hand.

Needed Repair: If your furnace has a distinct burning smell that seems impossible to identify, it could be that there is a dysfunction or some kind of structural damage to the unit. A lot can happen in the months that the furnace isn’t in use, and it likely won’t become apparent until you run it for the first time.  

What to Do? Repair work varies and it could be simple or complex. But depending on the extent and severity of the issue it could pose a potential fire hazard. That situation requires immediate attention from an HVAC specialist who can point you in the right direction and take care of any repair needs.

In general, if you’re noticing a persistent burning smell coming from your heating system, it’s time to call an HVAC specialist to take a look. Attempting to fix your heating system without the proper training or tools could void a warranty or lead to further functional problems. Instead, lean on the experts at Fred’s Home Services to tackle any heating related issue this and every season.

Burning Smell in Non-Central Heating Systems

Not every home in Northeast Ohio is outfitted with a central heating system. If your home utilizes baseboard elements or radiators to fend off winter’s cold, you’re still likely to smell the burn of accumulated dust when turning the thermostat up for the first time. But an electrical smell in the case of baseboard heaters, and a rotten egg smell in the case of radiators are both problematic and could signal a serious electrical issue or even the presence of mold or a corrosive substance called hydrogen sulfide. If the odor doesn’t dissipate quickly and no visible debris can be found, your safest bet is to cut power to the unit and contact an HVAC technician immediately. 

Call on Your Local Cleveland HVAC Specialists

A burning smell coming from your home’s heating system can be an everyday occurrence at the start of the heating season, but it can also be a real cause for alarm. Thankfully you don’t have to make that call yourself. The technicians at Fred’s Home Services are trained for this, and they can efficiently and effectively evaluate symptoms, diagnose the problem, and get you back to being comfortable and safe in your home. 

As we round the bend toward fall, it’s truly the best time of year to wind down air conditioning use with some DIY checks before things are buttoned up for the year.  Fall is also the best time to work through any heating issues. So if you’re looking for a new system, we’re ready when you are! Get in touch or give our team a call today to learn which system is best for your home or to set up an appointment. Now is the time––as the seasons transition––to be sure that you’re prepared to tackle any heating issues that the onset of colder weather brings.


Do you have any questions? We’ll be happy to answer them ASAP

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