Why Your Heater Smells Like Burning When First Turned On & What to Do

A burning smell from your heater can be alarming, especially during the winter season—it’s essential to understand the causes of burning smells to ensure your furnace or heating system is functioning correctly and safely. Burning smells from heat pumps or space heaters always require immediate attention and most likely the work of a licensed heating and cooling system technician. In traditional electric or gas furnaces, there can be many different reasons for a burning smell you notice after turning on your heater for the first time in months or at any time during the heating season. Some smells are completely normal and don’t mean you need to contact the fire department, but others could be a warning sign of trouble. In this article, we will go over the causes of burning smells in your furnace, including what is safe and normal and what is dangerous, and how you can prevent furnace dangers in the future.

Causes of Burning Smells

Burning Dust Smell

A burning dust smell is a common issue when first turning on your heater and is nothing major to worry about. It is caused when accumulated dust settles on the heat exchanger, blower motor, and air ducts during the off-season; therefore, when the heating unit is turned on for the first time in a while, the collected dust will burn off and create the odor. Though harmless, it can be an unpleasant smell, which can be prevented by regularly cleaning the vents and filters, especially before the heating season begins and your furnace has not been used for some time. If the furnace smell persists, you may need to replace your filter.

Electrical Burning Smell

An electrical burning smell is a serious concern that requires immediate attention, as it can indicate a problem with the electrical components of your heating system. Electrical issues, such as damaged wiring or an overheating blower motor, can cause a burning smell and potentially lead to a house fire if left unaddressed. If you detect this furnace smell, turn off the heater right away and contact an HVAC technician. Electrical wiring issues with furnaces can be prevented through regular professional inspections that can catch the problem early on before it grows into a serious concern.

Musty Smell

A musty furnace smell could indicate that you have an old filter that needs replacing or that the vents or ducts are dirty and in need of cleaning. This is also not an immediate danger, but it could cause health issues over time since you will be breathing in allergens, debris, pet hair, and other pollutants circulating through your system. Leaving ducts uncleaned can even lead to mold and mildew growth, which will also spread through your air. You can prevent this by performing regular maintenance tasks, such as changing the filter every couple of months and cleaning out your ductwork and vents before the winter season. If the odor persists, you can call a heating specialist.

Burning Plastic Smell

If your furnace smells like burning plastic or rubber, it is likely that something is stuck in the system that shouldn’t be there, like a toy or household item that might have gotten lodged in the vents or ductwork. This can become dangerous since plastic and rubber emit toxic fumes when they begin to burn, so it is best to shut down your system and try to locate the object in your vents if you notice your heater smells like burning plastic.

Chemical Odor

If you are detecting chemical odors coming from your furnace, this can be a dangerous sign. On a brand-new furnace, it is possible there may be a burning plastic or chemical odor that appears when you first run it, but this is typically a result of the protective coatings on the components of the new furnace. However, if you’ve had your furnace for a time and are detecting a chemical smell, it could mean there is a malfunction with the heat exchanger, which cycles heat from the combustion chamber into the plenum, which could catch fire if the exchanger is broken. Safety features will usually kick in and turn off the furnace if there is an issue, but there is always a risk of them malfunctioning as well. A chemical smell, particularly if it is a similar smell to formaldehyde, means there is a serious risk of fire and the leaking of carbon monoxide fumes. In such a situation, turn off the furnace immediately, open the windows, and call for an HVAC professional.

Rotten Eggs Smell

If your heater smells like rotten eggs, it is the typical sign of a natural gas leak if you have a gas or propane furnace. This is extremely dangerous, as natural gas is super flammable and toxic if inhaled. If you detect this strange odor, turn off your system and vacate the house right away before calling the gas company to repair the issue with the natural gas line.

Smoke Smell

A smoke smell coming from your furnace is also a bad sign, meaning you should turn the furnace off right away and open the windows. A smoke smell can occur when the exhaust vent or flue pipe becomes blocked, meaning the exhaust emitted by the furnace is not able to be vented safely through the furnace chimney. You should call an HVAC system specialist right away, and if the odor persists and the furnace smell is particularly strong, it is probably safer to vacate the house.

Other Smells

It is possible you may smell other distinct odors from your HVAC system, such as sewage or oil smells. If you smell oil, this could mean the filter is clogged if you have an oil heating unit. If your HVAC system smells like sewage, it could indicate an open sewer line or a broken wastewater line that is near your furnace. Both of these issues are best handled by calling a professional.

Maintenance and Prevention

Air Filter Maintenance

Regular air filter maintenance is crucial to prevent burning smells and ensure your heating system operates efficiently. Replacing air filters every three months can help reduce the buildup of dust and prevent clogged air filters. Cleaning or replacing furnace filters can also help eliminate musty odors and prevent the growth of mold and mildew. A clean air filter can help improve energy efficiency and reduce repair costs.

Reducing Dust Burning

Reducing dust burning can be achieved by cleaning vents and filters regularly, as well as scheduling regular furnace maintenance. Accumulated dust can be minimized by using a high-quality air filter and ensuring good airflow through the heating system. Regular inspections can help identify areas where dust is accumulating and prevent the furnace from smelling like something is burning. A well-maintained heating system can help reduce the risk of fires and ensure a safe and healthy indoor environment.

Air Vents and Ductwork

Air vents and air ducts play a critical role in maintaining good air quality and preventing burning smells. Clogged air vents can cause burning smells, as well as reduce the efficiency of your heating system. Regular cleaning of air vents and ducts can help prevent dust buildup and reduce the risk of burning smells. Clean ductwork can help improve indoor air quality and reduce the risk of health problems.

Safety Precautions

Safety precautions are essential when dealing with burning smells, as they can indicate a potential hazard before it becomes a serious danger. If you detect any alarming smell, it’s essential to immediately turn off the heater and contact an HVAC professional. Never attempt to repair electrical issues yourself, as this can lead to serious injury or death. Regular inspections and maintenance can help identify potential hazards and prevent accidents.

Prevent Dust Accumulation, Burning Odors, and More

If your heater smells like burning odors, it can be caused by a variety of factors, including dust accumulation, electrical issues, and gas leaks. It’s essential to understand the causes of burning smells and take prompt action to address any issues that arise. Some smells you won’t have to worry yourself about, and others are crucial to take action on immediately. Scheduling regular maintenance and inspections can help prevent unwanted smells and ensure your heating system operates efficiently and safely. For any emergency situation, furnace repair job, or professional maintenance tune-up, you can always call on the HVAC technicians at John Owens Services for assistance. We have over 30 years of experience working with all different kinds of furnace systems and resolve your issue right away if you are having trouble with furnace odors.

By following these tips and taking regular maintenance seriously, you can help prevent burning smells and ensure a safe and healthy indoor environment.