Why Does My AC Smell Bad?

Imagine walking into your home and smelling a terrible odor. Your AC is running, and the smell is circulating throughout every room. You look around trying to find the source, but it’s coming from everywhere. That’s when you realize it might be your air conditioner.

If your AC smells bad, there could be a handful of issues causing it, and it’s something you need to get taken care of as soon as possible. Whatever is causing the smell could make you or your family sick, damage your AC system, and cost significantly more to fix the longer it goes unaddressed.

Let’s look at what happens when your AC smells bad, what the different smells might mean, and how to get your AC smelling good (well, maybe just cool) again.

Reasons Why Your AC Smells Bad

Exhaust Fumes or Rotten Eggs

If you smell exhaust fumes or gas, open your windows and exit your home immediately. Call the fire department and your gas company to report a possible leak before doing anything else. While most AC units are not powered by gas, the system can still circulate gas from a nearby appliance or line leak into your home’s airflow. A rotten egg smell can also be caused by a small animal that has died in the ductwork, which is unpleasant but not a safety emergency. Once local authorities have cleared your home, that is when you call A.B. May Heating, A/C, Plumbing & Electrical.

However, your AC may also be circulating gas if other appliances or the gas hook up to your home is experiencing a leak unrelated to your air conditioning. This is why your first call if you smell exhaust fumes or gas is to the gas company and fire department, not A.B. May Heating, A/C, Plumbing & Electrical. Call us if it’s not a gas leak after checking with local authorities.

Skunk

A skunk-like smell coming from your vents is almost always a sign of a gas leak, not an actual skunk. Natural gas companies add a compound called methyl mercaptan to their gas specifically so people can detect leaks, and it smells remarkably similar to skunk spray. Follow the same steps outlined above: get out, call 911 and your gas company, and contact us only once your home has been cleared.

Burning or Gun Powder

If you smell burning from your AC vents, turn off your unit immediately. Check your home for any signs of the stove or oven being left on or any other signs of a potential fire. If you suspect something like this, call 911. If you don’t see any signs of a fire, open the HVAC closet or head down to where your indoor unit is and take a whiff. If you can smell burning or gun powder from the unit, chances are the circuit board or fan motor has or is in the process of shorting out.

Mildew

Mildew is the most common culprit when an AC smells bad. If you smell moldy air coming from your vents, mold or fungus are likely growing in or around your AC unit and may have spread into the ductwork itself. This is especially common in humid climates like Kansas City, where warm, wet conditions make it easy for mold to take hold. When moisture pulled into your system does not drain properly, it creates the perfect environment for mold growth that goes well beyond the filter.

Go ahead and change your air filter, but know it is probably not the root cause. The underlying moisture or mold issue needs to be diagnosed by a technician. Left untreated it will keep coming back and can affect your family’s indoor air quality over time. Schedule an AC repair visit and ask us about duct cleaning if the smell has been spreading through multiple rooms.

Feet

We’re not kidding here. If your AC smells bad and it smells like feet, you’re most likely dealing with an extremely dirty and clogged-up air conditioner. This typically starts with an AC that’s not draining properly so that water and all the dirt and debris within it starts pooling up and festering. The feet smell comes from that.

Can You Do Anything About AC Smells?

There are a few things you can do to reduce your AC pushing different smells through your home:

1. Change your AC filters based on manufacturer guidelines.
2. Install an air purifier if your HVAC system allows it. If not, have A.B. May Heating, A/C, Plumbing & Electrical make a recommendation on an air purifier system that will work.
3. Use exhaust fans when cooking, cleaning, and showering. This will help release chemicals and other smells outdoors instead of letting them get into your vents.
4. Consider the types of household cleaners you use. Anything with a toxic smell can and will make its way through your home.
5. Wipe down counters, appliances, dust, vacuum, and regularly sweep, as well as wash your linens and towels regularly to keep smells and debris from getting moved around your home by your AC.
6. Schedule annual maintenance to ensure your AC is performing at peak efficiency.

What Should You Do If Your AC Smells Bad?

Like every AC issue that pops up, our first recommendation is to change the filter. This does help with a variety of issues, including bad smells. If the smell persists, it’s time to call A.B. May Heating, A/C, Plumbing & Electrical to come out and diagnose what’s going on. We recommend annual maintenance and will work with you to determine the best scheduling for your home. Call us today and see how we can keep your home smelling good and keep the temperature cool during the summer.

Read More: Why is the AC Not Working in My House?

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