What Bad Smells Coming From Your AC System Might Mean

If you live in a warm climate, you probably depend on your AC unit to help you survive through those grueling summer months. In a situation like this, a broken AC can be devastating, and a weird smell coming from your AC can be downright worrisome. Here are some of the most common smells AC users have experienced and what they could mean for your unit.

Old cigarettes. If there’s a stale cigarette smell coming from your AC and no one in your family smokes, you likely live in an apartment or condo where previous tenants smoked indoors. The smoky odor has been sucked into the evaporator coil, permeated the ducts, and subsequently redistributed into your home every time the AC was used thereafter. An evaporator coil cleaning is the easiest solution.

Must or mold. If a musty or moldy smell is emanating from your AC, there is likely some bacterial growth festering within the unit. The smell could also be coming from a different source, such as a clogged drain line, and is simply permeating the ducts of your AC like old cigarette smoke might do. Basic AC maintenance can get rid of any bacterial growth.

Burning. This is one of the most common of the unusual scents that AC users have reported. A burning smell could indicate a serious mechanical problem within the AC, which should be inspected by a professional as soon as possible. However, if you’re turning on the heater for the first time since last winter, the burning smell could just be the settled dust within the unit mixing with the high heat.

Rancid garbage or decomposition. If you’re experiencing a smell like this, you’ll likely want to call a technician right away just from sheer disgust. If your AC is emitting air with a rotten tinge to it, you could be dealing with a dead and decomposing animal in the ductwork. A professional can remove the source of the smell relatively quickly, and the air coming from your AC will soon be back to normal.

Rotten eggs. A stench similar to rotten eggs coming from your AC could mean a natural gas leak. Though natural gas has no odor, most gas companies utilize a harmless chemical that creates a smell similar to rotten eggs when combined with natural gas. Make sure not to use any open flames, open the windows, leave the house if you can and place a call to your gas company right away.