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Florida’s been experiencing unusually warm winter weather lately. Central Florida was ready to break records with temperatures climbing into the 90s. In Miami, February proves to be ending with temperatures staying steady in the mid- to upper-80s, which is about 10 degrees higher than average. When it’s hot like this, your AC system is key to staying cool.

You’ve just cranked up your central AC and it reeks. It smells horrible. What causes an air conditioner to smell bad?

Describe the Smell

When an air conditioner smells bad, the cause of that odor determines what odor you experience. Yes, there are different smells and some are more serious than others.

  1. Gunpowder

When you smell a hot, metallic gunpowder smell, it’s usually linked to something electrical shorting out. It could be a fan motor or an AC circuit board. It can be any of the wirings for the power or compressors is overheating. Turn off your AC.

It’s important to call an AC technician to get the problem resolved as quickly as possible. Until it’s fixed, you’re not likely to have an AC system that’s working.

  1. Mold, Must, and Mildew

A moldy, musty, mildewy smell is one of the most common AC odors. Air passes through the ducts, and that air is humid. While the goal of the filter is to capture mold and mildew spores, as well as bacteria, dust, dander, and hair, things can get through, especially if the filter is dirty.

If you do have a musty or moldy smell, it’s often easily fixed. Check the air filter. If it’s dusty or clogged, you’re going to smell mold.

Change the filter and see what happens. If the odor goes away, great! If not, it could be mold and mildew build-up in the ducts. It’s time to call in an air conditioning technician for a full cleaning of your ducts.

In some cases, AC sanitization is ideal. This is especially true if there is visible mold within the ducts. You’ll want to have that cleaned and have the ducts sanitized to kill any possible bacteria that are also growing within the ducts.

During the cleaning, the technician will also check for any holes or cracks that could be allowing air to escape, which makes your system inefficient and drives up your bills.

  1. Oil and Exhaust Fumes

Your home smells like car exhaust. That burning oil smell that’s not pleasant. It’s concerning as your system is powered by electricity. While the system may be powered by electricity, there are other fluids within it, such as coolant or even sealed oil in the compressor or fan motor. If that oil is leaking out, you might start to smell it in the home.

This isn’t a problem for a homeowner to resolve. You need to bring in an AC repair expert to find the leak and fix it. If your AC system is old, you may find it’s more affordable to replace your system at this point, but a professional can talk to you about your options and what the cost is for each one.

  1. Rotten Eggs

The smell of rotten eggs is one of the worst smells to have coming from your AC system. It’s usually caused by an animal that’s found its way into your ducts and then died. A mouse, rat, squirrel, chipmunk, or bird could be the problem.

If an animal has gotten into your ducts and died, it needs to be removed. You also need to have your ducts sanitized and sealed to prevent other animals from finding their way in.

  1. Skunk Spray

You come into your home or turn on your AC and find your room smelling like a skunk. Turn it off, leave the house, and call an AC professional. A skunk-like odor can indicate a leak of methyl mercaptan, which is found in synthetic coolants. It’s not safe to sit and smell this gas. It can cause dizziness, nausea, headaches, and other troubling symptoms.

  1. Sugary and Sweet

If your system has a coolant leak, it can smell very sweet and sugary. It can smell a lot like brown sugar. Coolant is leaking somewhere, and that needs to be addressed ASAP. Not only is it bad for the environment to have coolant leaking somewhere, but your system isn’t going to cool effectively if it’s losing coolant.

  1. Sweaty Feet

The smell of sweaty feet is unpleasant. It’s usually one of two things. First, the air filter is clogged. Try changing the air filter first and see if that fixes the problem. If it doesn’t, the second problem is the likely culprit.

Your AC system has a condensate line. If that line is clogged, the condensation in the tray may be building up and getting stagnant. That will cause the smell of sweaty feet.

If this is happening, hire an AC technician for a complete cleaning and inspection of your AC system. You want to have the condensate line cleaned, all of the coils cleaned off, the air filter changed, if necessary, and the system tested and pressurized if it’s not properly pressurized.

  1. Wet Dog

Your AC kicks in and all you smell is a wet dog. If you’re experiencing the wet dog smell, it can be a dirty air filter. It’s almost always the air filter. If it’s not that, it could be that your AC is stirring up pet smells within the house as the air starts blowing into the room. Check your carpeting and upholstery to see if they have pet odors.

If you’ve checked those two things and it hasn’t resolved the wet dog smell, you might have a build-up of pet hair and dander in the ducts. It could be build-up on the evaporator coil or a drain pan with a plugged condensate tube. It’s a good time to have your ducts professionally cleaned.

Tips for Preventing Smells

The best way to prevent smells from happening is by making sure you’re taking care of your AC system. Have the system’s coils and vent covers cleaned each year. Get your ducts cleaned every few years. Make sure the condensate drain tube is clear and free of blockages.

You should change your air filter every couple of months. If you have a lot of pets or a dustier home due to a sandy yard, you might need to change it monthly.

Pay attention to unusual noises. If your AC is making noises you’ve never heard before, don’t hope they’ll go away. Call a technician and have the problem investigated and repaired if needed.

Call an Expert

Don’t suffer with a smelly AC system. All Year Cooling helps inspect your system and pinpoint the problem as quickly as possible. We’ve been helping Florida homeowners for 50 years and are happy to add you to our list of satisfied customers.

All Year Cooling is an FPL participating contractor. If it’s determined that you need a new AC system, we help you qualify for federal tax credits and FPL rebates to save money on your AC. Reach us via chat, phone, or by filling out the online contact form.

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