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The A/C Guy of Tampa Bay Inc. Blog

What Odd Smells From Your Central AC May Mean


One of the common warning signs of a problem with a central air conditioning system is when it starts to create weird sounds. But hearing isn’t the only sense you can use to notice an AC in trouble. Your sense of smell can also alert you. An air conditioner that’s blowing strange scents into your house through the vents is sending up a warning flag that you may need to call our technicians for central air conditioning in Tampa, FL.

If you’re currently noticing a strange AC smell, we can help you try to narrow down what it means. Please don’t try any repairs on your own—leave the diagnosis and solutions to our professionals.


Does the moldy odor coming from the AC remind you of dirty, unwashed socks? Then it looks like your AC has the well-named “dirty sock syndrome.” The source of this moldy smell is probably, well, mold. In our humid climate, it isn’t difficult for mold to begin to grow inside the AC, usually along the evaporator coil where moisture can accumulate. It’s much more likely to happen in an AC that hasn’t received regular maintenance. Mold not only smells bad, but it interferes with heat exchange in the AC which will lower the system’s efficiency. Plus, mold can release toxic spores into the air.

Acrid burning

You might think of this as an electrical burning odor, and that does go straight to what’s likely gone wrong in this case: electrical components in the AC are burning out. A likely candidate is a motor, and its fusing wire cases are giving off this odor. It might also be trouble with the control board for the AC. No matter what, shut down the AC and have experts take a look, because you may have an electrical fire in the HVAC system.


Yes, that unmistakable “rotten egg” odor that people connect with natural gas. As they should, because this is what’s probably causing this smell. Natural gas is odorless, but manufacturers put a special chemical into it so people can notice it in case of gas leaks. But why is there natural gas coming from an electrical device like an AC? If your AC is in the same cabinet as the furnace, it’s near gas lines—a leak could lead to the air conditioner blowing the gas around the house. In this case, don’t call us first. Instead, shut off the gas to the house and the AC, leave the house, and call the gas company.

Sour trash

Ugh, this is one of the worst odors you can have in your house. However, if you smell this coming from the vents when the AC is running, it’s probably not the HVAC system at fault—you may have a dead animal in there like a rat. Our technicians can access and clean out the ducts, and we also recommend you call animal control. (You really don’t want to deal with this icky problem on your own!)

The A/C Guy of Tampa Bay Inc. serves our Tampa Bay family with integrity and honor. Call us for any repairs you may need for your air conditioning system.

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