Very sudden burning smell in vents that aren't even on.?

Could you possibly have something dead in the ceiling/walls? Squirrels, mice, etc. may also be nesting in the walls/ceilings. I experienced this in my last house, it lasted about a week badly and about 3 weeks mildly. It was awful, I had a pest control company come out and shore up a few areas under my eaves that squirrels were getting through.

I would also contact an electrician to determine if there was a short somewhere or see if those same critters ate through my wiring.

you could favor to get a clean ac guy because this one would not look worried about a burning scent at your position of abode. it really is maximum likely on the problem of the blower motor. The capacitor would properly be undesirable, that can reason the motor to overheat. Or the motor bearings would properly be getting worn. He ought to a minimum of examine those ability motives. He would not ought to capture it shutting off or making a scent to envision that a lot. interior the intervening time, your compressor would properly be damaged. Any time the blower shuts off at the same time as the compressor is operating liquid refrigerant will flood the compressor - no longer a good situation! each and every person interior the south are busy with ac calls yet 5 days??? Gimme a smash! solid success! Jack

Check near ur furnace in the basement? Could have an electrical fire about to start(shorted wires, or mouse chewed on wires?) I would guess that ur furnace is somewhat near just under your living room.