This one needs a licensed pro
Stop: burning plastic or an electrical smell
A burning plastic or electrical smell from a furnace is a safety problem. Turn it off and call an HVAC technician.
Why this happens
Trane says a burning plastic smell can mean an electrical problem, such as the coating on a wire melting, and calls it a big safety hazard. Carrier says burning plastic or an electrical smell can come from an overheating blower motor or damaged wiring, and that you should stop using the furnace until a qualified HVAC professional inspects it.
What to do right now
- If you see smoke or flames, or the smell gets much stronger, leave the house and call 911 from outside. If you smell gas or rotten eggs, leave now, touch no switch, and call 911 or your gas utility from outside.
- Set the thermostat to Off. Carrier also says to shut off power to the furnace. If the furnace has its own power switch on the outside, and you can reach it without going near smoke, a hot spot or a scorched area, with dry hands and a dry floor, switch it off. If you can't do that easily, skip it and go on to the next step.
- Don't turn the furnace back on until an HVAC technician has inspected it.
- If the smell persists while you wait, Carrier says to turn on exhaust fans or crack some windows, because burning plastic can give off fumes that are not just unpleasant but can be toxic.
- If the smell is strongest at an outlet, a switch or something plugged in, not at the furnace, don't pull the plug while the outlet is hot, smoking or sparking. Follow the guide for an outlet burning smell, which turns the breaker off first.
- Don't open the furnace, and don't try to find or fix an electrical or gas problem yourself.
- Call an HVAC technician.
When to stop. If you see smoke or flames, leave and call 911. If you smell gas or rotten eggs, leave the house and call 911 or your gas utility from outside. If a carbon monoxide alarm sounds, or anyone has a headache, dizziness, weakness or nausea, get outside to fresh air and call 911.
What to tell the HVAC technician
- What the smell was like, and where it was strongest: the registers, the furnace or somewhere else.
- Whether it started the moment the furnace turned on, or a while later.
- Whether you heard a hum, grinding or any other new noise.
- The brand, model and age of the furnace, from its data label.
Build the full list: what to tell the HVAC technician.
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