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Why Does Your Air Conditioning Smell Horrible?

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When you turn your air conditioner on, you expect it to fill your home with nice, cool air -- not with a terrible stench! Nobody wants to live in a smelly home all summer, and odors can be an indication of a serious problem with your air conditioner. So clearly, this is not an issue that you want to ignore. Here are a few possible causes of the smelly air.

1. Mold Growth

Does the odor remind you of an old, wet basement or of spoiled food? It could be caused by mold growth. Mold can grow in the cuts that carry the air from the air conditioner to your vents. Or if you have a ductless AC system, it could accumulate in the tube leading from the outside condensing unit to the air handler. Mold can also grow within the air conditioner itself, particularly if the condensate drainage tube gets clogged and water starts flowing all over the air conditioner.

You can check the condensate drain tube for blockages yourself. If there appears to be a blockage, use a pipe cleaner or long wire to clear it out. Or, detach the drain tube, buy a new piece of drain tube in the same diameter, and attach it to the drain. If you think the mold may be coming from inside the ducts, you'll need to hire an AC contractor to come clean the ducts. The equipment to reach inside the ducts is quite specialized and not something you can buy at a home improvement store.

2. A Dirty Filter

The air filter is meant to trap contaminants in the air. If there was previously a smelly episode in your home -- maybe you burned something in the kitchen or your pet was muddy and smelly -- remnants from the event might still be left in the air filter. When the AC turns on, some of them end up propelled through your home. Try changing the filter out for a new one, and dispose of the old one in the outdoor trash. This just might fix your stinky problem.

3. Electrical Issues

Does the odor have a metallic or burning quality to it? Chances are that your AC unit is experiencing some electrical problems. Certain components might be getting too hot and even smoking because of a short or loose wire. There should be emergency overrides built into the AC unit that cause it to turn off when such an electrical problem occurs, but these can sometimes be faulty, too. Turn the air conditioner off, and do not use it again until an electrician or your AC service contractor has given you the okay.

4. Dead Animals

The idea of a dead raccoon or rat in your ducts may sound disgusting, but it is a real possibility. If the smell reminds you of decaying flesh, you should look into this possibility. Turn the AC off, and have a professional send a camera down into your ducts to see if a dead pest is in there. You may also find the feces of pests like rats and mice, which can also cause a stench. Your AC contractor can remove the animal or feces and then clean the ducts so you can enjoy fresh air once again. They will also want to block off access points through which the animal may have entered.

Too many homeowners suffer through stinky air conditioning emissions, figuring they are just par for the course. But a stench is never normal. Describe the smell, to the best of your ability, to your local HVAC company, such as Air Around the Clock. They can send someone out to help.