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Reasons Your Heater Smells Like It’s Burning

Your furnace may emit different smells, especially if it has not been in use for a while. Some of these smells may not be a cause of alarm. However, if your heater smells like burning plastic or metal, this may indicate a serious issue that would require an HVAC expert. If you sense a burning smell from the furnace vent after the first few instances during the fall or winter, make sure to call an expert to give it a clean bill of health before the weather gets worse. Some of the various burning smell from furnace vent and what they could mean include;

The furnace smells like burning dust

If your heater smells like burning dust, then you may not have a significant problem to worry about. It may probably be due to dust accumulation that settles on your furnace when not in use. The dust usually disappears within two uses of the furnace. However, if the smell continues, you may have to check your filters, clean them, or install new ones to get rid of the smell.

The furnace smells like burning plastic

The plastic smell may be the presence of a foreign plastic object in the furnace. For example, if you have toddlers and young children, you may experience this a lot with your children throwing their toys in the most unlikely places. However, if there is no foreign thing in the furnace, then the plastic object may be from capacitors, plastic-coated wires, or fan belts burning on the inside. In this case, it is essential to switch off your furnace and have it checked by an expert as plastic fumes may be dangerous to your health.

The furnace smells oily or smoky

An oil furnace is likely to emit the smell of oil or smoke, especially when overheating occurs. In such instances, change the oil filter and test to see if the smell goes away. However, if the smell persists, switch off the furnace and have it checked by an expert as the problem may be more significant than what meets the eye.

The furnace smells metallic or electrical

Most furnaces have a safety feature known as the blower motor or the heat exchanger, whose primary function is to automatically shut off when it starts overheating. However, if the blower motor is faulty, this is unlikely to happen, making your furnace emit a metallic or electrical smell. It is an indication that the furnace is destroying the inner equipment and should be switched off immediately. You should then call an HVAC expert to check it out before you use it again, as this may lead to severe malfunctions.

Smells like burning gun powder

The gun powder smell is a specific smell that is emitted by a spoilt circuit board or fan motor. If you start experiencing this smell, it is essential to switch off the furnace and have it checked to replace your fan motor.

The furnace smells like rotten eggs

Since natural gas is odorless, most companies add Sulphur to help you identify a leak. When you smell a rotten egg, kindly switch off your furnace and have everyone go outside before calling the fire department or gas company. This smell is caused by gas leakage and may easily cause death through suffocation.

Furnace smells mildew

If you are using your furnace and it smells moist or damp, then the air filters may fail or need some cleaning. Clogged air filters are likely to emit a musty smell. You should also check your humidifier if your furnace has one to see and inspect it for molds. Molds not only pose a health challenge to your family, but they are also tough to get rid of.

However, It is possible to get rid of them by cleaning the humidifier with vinegar and water. In case the smell continues, then call an HVAC expert to have it checked out, as the molds may have infiltrated deeper into your furnace. You should also check to see if there is any dampness in your walls or foundation that may lead to mold build-up and adequately deal with it.

Overheating/Faulty air Filters

A burning smell may also be experienced from the furnace vent due to clogged air filters in some instances. If something hinders your air filters from properly functioning, the furnace may emit a burning smell due to the overheating experienced inside. It may also be an indicator of faulty air filters. You can try resolving this by removing the air filters and thoroughly cleaning them or replacing them with new ones if those present are faulty.


Your furnace plays a vital role in keeping you warm. It may not need frequent repairs; however, having it checked at the beginning of winter or fall before you start using it is essential to ensure it is in good shape.  It also ensures any faults are identified early and promptly corrected to avoid gas leakages, electrical malfunctions, or fires that may lead to death or place your life at risk.

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About CoolPro Heating & Cooling

CoolPro is a family-owned and operated HVAC company providing heating and air conditioning services, repairs and installations to commercial and residential properties.

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