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Why Does My AC Smell Like Chemicals?

Wondering about that strong chemical odor coming from your air vents when you turn on the AC?

A chemical odor could be caused by any of these 4 problems:

  1. Open containers of chemicals near indoor air handler
  2. Refrigerant leaks
  3. Ozone from electronic air cleaner
  4. Glue in new ductwork

Let’s go into more detail about each of these and how to solve them, starting with the problems that are easiest to fix.

Problem #1: Open containers of chemicals near indoor air handler

Your AC is comprised of an indoor and outdoor unit. In Twin Cities homes, most indoor units (also called air handlers) are located in a basement, closet or attic. Many homeowners use these spaces to store cleaning or paint supplies.

If these chemical containers are open or leaking, your indoor air handler will pick up those fumes and blow them into your home.


Locate your indoor air handler and check for open/leaky chemical containers. Close any open containers and throw away any leaky containers.

Problem #2: Refrigerant leaks

Refrigerant is the lifeblood of your air conditioner. Your air conditioner uses refrigerant to remove the heat from your home’s warm air. Refrigerant travels through closed copper coils (think of the coils as the AC’s veins).

Over time, sometimes these copper coils crack and leak refrigerant. Refrigerant has a sweet, chloroform scent, so that could be the chemical odor you’re smelling.

If you do have a refrigerant leak, you’ll notice other signs like…

  • Warm air coming from your AC vents (except on cool nights)
  • Ice on the refrigerant lines
  • A hissing or bubbling noise near your AC
  • High energy bills


You’ll want to contact a licensed professional to inspect your system if you think you have a refrigerant leak. Only a certified technician should handle refrigerant because it’s a toxic, flammable gas.

Learn more about refrigerant leaks:

Problem #3: Ozone from electronic air cleaner

If you have an electrostatic air filter, it may be the source of the chemical odor you’re smelling. During normal operation, most of these filters produce ozone, which is an inorganic molecule with a scent similar to chlorine.

If you’re exposed to unhealthy levels of ozone from your air cleaner, you’ll notice a stronger odor. Additionally, you could experience symptoms like chest pain or shortness of breath.


Try adjusting your filter system to a lower setting (look at the manufacturer’s instruction manual for help) so it doesn’t produce as much ozone. If you still notice the smell, contact an air quality expert to take a look at your air cleaning system.

Problem #4: Glue in new ductwork

Do you have new ductwork? If so, the new glue that holds the ducts together could be causing the chemical odor you’re smelling.


Unfortunately, there’s not much you can do to get rid of that smell. Over time, it will go away naturally. In the meantime, you can try using air fresheners to dampen the smell.

Still can’t get rid of that odor?

Contact MSP to schedule an appointment with one of our trusted techs. We’ll get that unpleasant chemical odor out of your home in no time.

We’ve been serving families in the Minneapolis-St. Paul metro area since 1918.