Why Does My AC Smell Bad? – Part 1

That pleasant feeling of Cool Fresh Air when your home’s central cooling system kicks on can be ruined if it doesn’t smell so fresh. “Why does my air conditioning stink?!”, you’re worrying either to yourself or out loud. Are gross odors normal? Should I just ignore it? The answers? “No”, and “NO!”. A properly maintained and operating central A/C system will not smell bad. So if that’s what’s bothering you, then you need to get it taken care of. If you simply want it gone ASAP, then call GAMA Air at (323) 655-6126 or use our online form to schedule a System Tune-up & Safety Check.

For the benefit of our friends and neighbors in the Beverly Hills, Culver City, Mar Vista, Miracle Mile, Hollywood, West Hollywood, Los Angeles, West Los Angeles, Santa Monica, Marina Del Rey, Pacific Palisades, Brentwood, Bel Air, Westwood, Downtown Los Angeles, Vernon, Huntington Park, Sherman Oaks, Encino area, we’re going to address the six smells that are most commonly experienced, and what to do about them. The type of smell is a clue to the cause. Let’s get started with a brief explanation of the most likely cause of the foul odor, and then we can get into the possible fixes for it.

My AC smells like a skunk

This is the worst one because of the possible cause. The substance methanethiol, also called methyl mercaptan, is a gas that smells a lot like the spray from a skunk. It is an additive put into propane gas and natural gas to give these otherwise odorless gases a strong and obnoxious smell to alert people to the presence of a gas leak. Even though propane or natural gas is not used for your air conditioner the fan could be circulating the leaking stinky gas throughout your home. Since this smell could indicate a hazardous gas leak, that means the issue is potentially dangerous. Don’t turn on or off any switches, get your family out of the house, and contact the emergency line of your trusted heating and cooling service company.

My AC smells like stinky feet

We hear about this the most, about an unpleasant “dirty sock” smell. Others describe it as a musty smell, or a mildew odor. This smell comes from standing water in a dark place. Water that does not drain out of the AC properly will collect and begin to smell, giving off that “stinky foot” smell.

My AC smells like mildew

This is probably the second most common complaint we hear in the “nasty smell” category. The standing water we talked about in the “stinky feet” description above will eventually lead to the growth of mildew, or worse yet, the growth of mold. Both mildew and mold can easily grow where there is a constant source of moisture. If you smell it, then it is very likely in your units or duct work.

My AC smells like rotten eggs

This is a less common stink, and the cause is slightly more morbid. The “rotten egg” smell is nearly always the result of a dead animal. You are more likely to smell this the first time you turn on your system after the mild spring or autumn season when maybe it wasn’t running for some period of time. A small bird, mouse, or other rodent might have gotten its way into the ductwork where it died and began to decompose. Then when you turn on your central heating and cooling system for the first time after that, a horrible odor blows out of the vents and into your home. The smell of decomposing flesh gives off that rotten egg odor.

My AC smells like exhaust fumes

Technically this isn’t possible. Your central AC system does not run on gas or diesel or any other fuel. However, there are smells that could make you think of exhaust fumes. There are other fluids that could leak out or other aspects of an air conditioning system that could cause a odor similar to exhaust fumes.

My AC smells like gun powder

This is even more impossible than the exhaust fume smell, since gun powder is definitely NOT used in your air conditioner. However, once again, it is what comes to our mind when we smell it that matters. And there are components of your home’s AC that could smell like that. An HVAC technician would likely call it a ‘burnt electronics’ smell, and it could come from shorted circuit board or an overheated fan motor.

What can you do to address these stinky smells? We’ll cover that in an upcoming blog post. So come back for more information.

Do you have a nagging question about a situation you have with the heating or cooling in your home that you need answered ASAP? Visit our Ask an Expert page and fill out the form. We’ll get our resident expert to send an answer to you fast!

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