How to Troubleshoot Home AC Smells

Change the air-conditioner filter. When the smell is damp and musty, chances are that the filter has gotten wet. When you smell dirt and dust, it's just dirty, so change the filter. If you have pets, especially cats, you will probably need to change the filter twice as often. If the filter has gotten wet, investigate the source of the dampness and eliminate it.

Vacuum the air-conditioning ducts. This applies primarily to central air-conditioning units. After changing the filter, if the smell persists, you may need to clean the ducts. Attach the upholstery brush to your vacuum and remove the vent covers in your home. If there's a large amount of dirt and debris, consider calling in a specialist. They have special equipment such as long hoses that enable them to do a more extensive cleaning job.

If the odor is especially strong and you suspect that there might be a dead animal such as a mouse in the ducts, then you need to use rubber gloves and disinfect the area immediately. If you can't reach the animal, call in a specialist.

Scrub the air-conditioning ducts with a bleach solution. After you vacuum the ducts, scrub them with a weak bleach solution. This will not only clean dirt but it will also clean any mold that might be growing. If you've been smelling mold, this will kill it.

Call a heating and air-conditioning repairman. When the air conditioner has the odor of burning plastic or wires, it's time to call in a repairman. Shut the unit off and wait until it's fixed before using. If you have electrical skills and know what you're doing, you can check the wires and connections yourself. To avoid the risk of electrocution, turn off the main power breaker to your home before beginning. Check for loose wires, rusted wires or scorch marks. Remove rust with steel wool, secure wires using electrical tape and turn on the power.