Updated at: 14-02-2023 - By: Sienna Lewis

It’s possible that when you finally switch on your air conditioner for the first time this season, you’ll inhale something foul-smelling. You may be freaked out by the scent at first, but don’t worry; it generally fades after the first use. To avoid unpleasant smells, it’s important to perform AC maintenance before closing down and again before starting up in the spring.

When you initially turn on your air conditioner, it may smell. Here’s what’s going on:

Have You Maintained Your AC Yet? Schedule Your Spring Tune-Up!

To get rid of unwanted scents from your air conditioner when it’s initially switched on, follow the advice in this article. Call Arctic Air Conditioning if the odor persists for more than a day or two. Whether you’re having issues with foul odors or not, we can help you get the most out of your air conditioner with our AC maintenance services. If you’d like to get in touch with us about scheduling a service in central New Jersey, please do so right now!

What to Do When Your Air Conditioner Smells Bad • Peninsula Air Conditioning

Air Conditioner Smells Bad When Turned On

7 Reasons Why Your AC Smells Bad When Turned On

1. Dirty Air Filters

Mold and mildew can accumulate on air filters and spread bad aromas throughout your home if they aren’t properly replaced at the regular intervals. Air filters’ natural purpose is to gather dust and other airborne particles. Your air conditioner’s effectiveness will be negatively impacted by dirty air filters, which can lead to a host of other issues. As a result of these factors, it is critical to inspect and replace your air filters on a regular basis.

2. Dirty Evaporator Coil

A filthy evaporator coil is another major cause of poor AC scents. In order to circulate cool, fresh air throughout your home, the evaporator coil converts the liquid refrigerant into gas. It is possible, however, for these coils to become overly wet and thus the growth of mold and mildew. While it’s possible to clean these coils on your own in some cases, it’s always best to enlist the help of a professional. To clean your air handler’s coils, simply locate them within an access panel and use a soft brush and warm water combined with a light detergent (the interior unit).

3. Problems in Your Ductwork

Pathogens from the outdoors can get into your air ducts and cause mold and mildew, which will emit foul odors throughout your house if they are damaged or leak. Leaky air ducts can cause uneven cooling in different rooms and even after operating the AC for a long time. Calling a professional HVAC expert is always preferable to patching minor holes yourself. The ducts may be safely cleaned and sealed against further leaks and damage using specialized equipment. They’ll be able to check for any other issues that may be present as well.

Why My Air Conditioner Smells When Its On in Maryland Heights

4. Clogged Drain Lines

Algae, mold, mildew, bacteria, and other microorganisms can grow in your condensate drain line if it becomes clogged. When your unit’s heat exchange process involves removing excess moisture, these drain lines are designed to do so. However, malfunctions, damage, and wear and tear can lead to problems. It’s possible to fix most clogs with a few ordinary household objects and a little effort. For more serious drain line issues, a professional’s assistance may be required.

5. Stagnant Water in Drain Pan

Water might accumulate within the AC drain pan if drain lines become clogged. Fungal growth, mildew, and other nasty things thrive in stagnant water. If you see any water in your AC drain pan, use a towel or a wet/dry vac to remove it, and then use vinegar, bleach, or another cleaning solution to disinfect the pan. For more serious issues, you’ll either need to have your drain line cleared or hire an expert plumbing service to do it for you.

6. AC Smells Like It’s Burning

For a brief period of time, your AC unit may emit a burning odor when it burns off dust that has accumulated over a long period of time, such as when you switch on the heater during the cold season for the first time. Once you’ve used it a few times, you should no longer notice this. Professional help may be required if the scent persists, or if your unit hasn’t been dormant for a long period of time. There are a lot of electrical components in air conditioners, and they can catch fire. If you can’t figure out what’s wrong, call an HVAC pro.

7. AC Smells Like Chemical Fumes

Because of a refrigerant leak, you may notice unusual odors coming from your air conditioner while it is running. During a cooling cycle, your air conditioner distributes cooled air throughout your home thanks to refrigerants like freon. These compounds are fantastic for cooling the air, but they can be harmful if they come into direct contact with the skin. Many serious effects and even death can result from refrigerant poisoning, which is caused by inhaling refrigerant.

Immediately turn off your air conditioner if it is releasing chemical or exhaust-like odors. Seek immediate medical attention or dial the National Poison Control Hotline at 1 (800) 222-1222 if you have difficulty breathing or have been exposed to refrigerant in any way.

Improve Your Air Quality With Complete Air Mechanical

Your home or business’s energy efficiency can be guaranteed by the expert HVAC technicians at Complete Air Mechanical. Our services are available throughout Orange, Osceola, Seminole, and Volusia counties, and we have financing alternatives available to those who qualify.

Mold on the Evaporator Coil & Fins

Dirt, dust, and moisture build up on the indoor evaporator coil when the unit is not used for an extended length of time. Mold thrives in this type of atmosphere. Mold’s decomposing odor is carried into your home as the air travels over the evaporator coil and fins for the first time this season.

The evaporator fins should be cleaned with water and a few drops of mild detergent each fall to help prevent unpleasant stench. Before turning on your air conditioner for the first time in the spring, repeat this cleaning procedure.

Mildew on the Air Filter

When the air conditioner is running, it can emit a musty odor because of the accumulation of dust, hair, and moisture on the AC filter. If you don’t use forced-air heating in the winter, your air conditioner may smell when it’s turned on for the first time.

Spring is a good time to clean or replace the filter to help reduce the stench.

Algae & Mold in the Drain Pan

As air conditioners remove excess humidity from the air, they produce condensate. Mold and algae can grow in a drain pan as a result of this dampness. When you turn on the AC for the first time, an unpleasant stench may be generated as a result of this clogging the drain.

Why Does My Air Conditioner Smell? | BR McGinty

Before turning off the air conditioner for the season, be sure to clean out the drain pan. Spring cleaning with diluted bleach removes any remaining odors, allowing for a fresh start to the cooler months ahead.


When you switch on your air conditioner, it emits a noxious odor. Similarly, there are a variety of ways to accomplish the same goal; some are universal, while others are more specific. If you are unable to perform the task on your own, you may want to consider hiring an HVAC specialist.