Is your air conditioner releasing a bad or weird smell into your home? What does it mean, and can you fix it yourself? Below we walk through 4 common smells that might be coming from your air conditioner, what it means, and whether it is cause for concern. As with all HVAC questions or concerns, always call an HVAC technician if you are unsure!
1. Rotten Eggs
If you smell sulfur or rotten eggs, that almost always means there is a gas leak in your house. Natural gas is odorless, but gas companies add the smell so you know when there is a leak. The gas reduces oxygen levels in your body which can be fatal. It can also catch fire and explode. If you suspect a gas leak, turn off your gas supply immediately and call your local fire department.
If you just turned on your air conditioner for the first time in several months and it smells like something is burning, this could be dust burning. Wait a few minutes to see if the smell dissipates. If it does not go away, the burning smell could be a mechanical problem and a fire hazard. Switch off the system immediately and call an HVAC technician for an emergency repair.
The smell of gunpowder is associated with electrical odors. This odor is very distinct and should never be ignored. It is likely caused by a fried fan motor or circuit board. No matter the culprit, you will need to get your AC repaired before using it again. Switch off the system and call an HVAC technician for a repair before turning on the unit again.
4. Mold or mildew
Smelling mold or mildew when your air conditioner switches on is quite common. When your air conditioner cools the air, condensation builds up and needs somewhere to go. If your condensate drain line is clogged, this moisture has nowhere to go, allowing mold and mildew to grow in the unit and in your ductwork. Shut off your unit and check the drain line and indoor AC unit for mold and mildew. You can unclog a drain line and clean an AC unit yourself, but if you have never done this before, we recommend calling a professional.
There are a variety of less-common odors that can come from your AC unit, including chemical smells, exhaust, or something that just smells terrible. Always turn off your unit if you think something is wrong and call for an AC unit inspection and repair. Allowing your unit to continue to run could be damaging the unit itself and be hazardous to your health.