Why Does It Stink When I Turn On My AC?

How would you feel when you return home from a long day at work in the scorching sun only to listen to unusual noises and unpleasant smells when you turn on your AC? Having an air conditioner that smells bad can ruin your mood and make others living indoors feel miserable. Therefore, it is recommended to immediately reach out to the best HVAC service in Austin, tx, and get rid of the bad stench.

Why Does Your Air Conditioner Stink?

What are the various types of smell coming from your AC, and what do they indicate? Let’s find out the solution to all your questions.

Smelling Like Exhaust Fumes

If your AC unit gives out a smell resembling exhaust fumes, there is likely a fluid leak within the system. Air conditioners use various fluids while running, especially from the refrigerant section. Refrigerants like freon provide cooling cycles within the unit and ensure comfort. However, if it starts to leak, freon is hazardous to the environment and may cause fatal effects to anyone who inhales it.

Smelling Like Rotten Eggs

If your home starts to smell like rotten eggs, there may be a dead animal somewhere. This can be birds or rodents who often take shelter in the air duct of your AC during the winter. Lizards and other critters may get stuck inside the unit and give an unpleasant smell. You can handle this situation by locating where the stench is coming from and pest-proofing your system.

Smelling Like Mold And Mildew

If there is an accumulation of dirt and moisture within the air conditioning equipment, such as the evaporator coil or the air filter, you may be exposed to mold and mildew. Living in a hot and humid climate and using your AC for a long time can also cause moisture accumulation. Therefore, it is advisable to prevent mold and mildew by frequent tune-ups, fixing water leaks, improving drainage, and replacing HVAC filters.

Smelling like skunk

This is an alarming situation and needs to be given immediate attention. If you notice a skunk-like smell coming from your AC unit, it indicates a likely gas leak, particularly methyl mercaptan. This gas is harmful to human health, and it is advisable to evacuate anybody in the room as a first step. Moreover, you can immediately turn off your gas supply and wait for the technical team to arrive.

Smelling Like Cigarette Smoke

This is a likely situation if anybody at your residence has the habit of smoking indoors. If a person smokes indoors, the AC units, such as the air filter and the evaporator coil, tend to absorb the odor coming from cigarette smoke. This leads to your AC giving out a stale cigarette smoke-like smell and can lead to allergic reactions and headaches. This situation can be prevented by changing your air filters within 1-2 months and cleaning your unit regularly.


Any stench or noise coming from your HVAC system indicates that your unit isn’t functioning properly. It is advisable to reach out to an AC tune-up near me. If you are looking for professionals in this field, you can contact us online or call us at (512) 759-4247.