Why Does My Furnace Smell Like it is Burning Up?

A burning smell coming from your home heating is something that needs to be addressed right away. Unplug the furnace and call.

The Furnace Smells Like it is Burning Up?

Caution – Caution – Caution

What makes a Heater Smell like it is Burning?
What king of burning smell is coming from your heater or furnace?

Plastic Burning Smell Coming From the Heater.

The Motor: If your furnace or ducts smell like plastic is burning you need to turn your furnace off right away and unplug it. Unplugging it or turning of the circuit breaker is the only way to truly protect your home and family from a furnace burning down your home. Over the years I have seen many home catch on fire because of a short circuit in the furnace. Protect yourself now.
The most common burning smell that smells like plastic from a home heater is the windings on the motor short circuiting. Usually the motor still runs, but at a slower speed. Occasionally the motor will not turn off at all until power is disconnected from the HVAC system.
The motor windings are covered in a lacquer like coating on motors and many older motor also contain paper. When the winding wear out or short out the copper conductors in the motor ground to the sides of the armature or case of the motor housing. This completes an electrical circuit and can energize the entire furnace with 120 volts. Yes, you can be shocked by this. This circuit is now a resistive circuit. It is just like the toaster heater coils on your kitchen counter. They grow hotter and hotter until the motor starts burning or the winding insulation starts burning. This can fill your home with a very rotten smell that is very difficult to remove.
The Transformer: Transformers in furnace are very sensitive to short circuits. Homeowners often burn out their heater transformers when changing or upgrading their thermostats. The green wire is not ground on a furnace 24 volt circuit. The transformer, when burnt, smells sickly sweet. The furnace will no longer function, but most often the furnace fan motor will run in lower speed until the power is disconnected. The circuit board turns on the fan motor when there is a break in the 24 volt safety circuit. It thinks the furnace is burning up. The burners are shut down and the fan motor is energized to cool the furnace down.

A Dirty Polluted Burning Smell is Coming From the Heater.

This furnace burning smell is exactly what I just wrote, a dirty polluted furnace. This type of burning smell that occurs typically once a year when the heater is first turned on and usually goes away within a couple of weeks is from:

Lack of proper maintenance. Dirt, debris, pollen, animal hair, dead human skin are built up in the furnace on the heat exchanger (firebox) and when the burners kick on this gross concoction is heated up to the point of burning. Yuck.
Dead animals in the ducting, evaporator coil or furnace blower compartment. Rats and other rodents do exist in people's homes and they can cause terrible furnace smells when the system is operating.
Improperly install condensation drain. Fly by night HVAC companies cut corners (always get a permit for the installation) and many will drain the condensation from the air conditioning system into a sewer vent. As long as there is water in the condensation trap nothing is noticed, but stop using the air conditioning and the furnace and duct work can fill up with poisonous sewer gases and make a home unlivable.

Whatever problems you are experiencing with your home heating system, smelling bad, burning smell or other, don't worry. We have experts on staff that can answer all your questions and perform nearly every repair the same day we arrive at your home. You've already taken the first step towards a healthier home by arriving at this furnace website. The next step is only a phone call away. Call now and book your appointment for a cleaner safer tomorrow.