Skip to content
Drake Heating & Air, Heating & Air Conditioning, Eaton, OH

Are there strange smells coming from your air vents?

We generally take the air flow in our house for granted – that is, unless there’s a strange odor coming from the air vents. These odors can be barely noticeable, or they can be unpleasant and annoying. But they almost always mean something is going on with your HVAC.


If there’s a musty odor: There might be a problem with dampness somewhere. When it’s coming from your vents, it may be difficult to pin down the source but it’s important to do so. While mold and mildew will not hurt your equipment in any way, it can certainly be a negative to the health of people in your household. Poor air quality can lead to sinus and respiratory health issues.


There are several possible reasons for a musty odor.

  • Running the air conditioner a lot can cause a buildup of condensation within the unit. If the moisture from that condensation doesn’t get properly drained away, it can get into your ductwork and become a breeding ground for mold and mildew, which is then blown through your hose through the vents. The solution is to have an HVAC technician find where the mold is building up and then clean it out properly.
  • Another problem might be that your air conditioning unit is too large for the size of your home. A bigger unit is not always better because one function of your air conditioner is to dehumidify the air as well as lower the temperature. If the AC unit is too big, it will cycle off too quickly and not dehumidify the air properly. If this is the case, consult with an HVAC provider to see if your unit is too large, and perhaps go over your options for a high-efficiency replacement.
  • Sometimes a musty odor is an indication that bacteria is growing on the coils of your air conditioner or heat pump. If that is the case, the easy remedy is to have a routine maintenance call or schedule a tune-up.


If there’s a burning odor: This could be just dust burning off your equipment the first few times you turn on your furnace for the season. If the smell is faint and doesn’t linger too long, you don’t need to worry. Dust is going to gather on the heat exchanger of the furnace during the off season. It burns off when the furnace goes on for the first time in a while.


However, if the air from your vents smells like something is overheating, this could be a more serious problem. It might be caused by an air filter that has become too dirty and clogged, restricting air flow and causing the electric resistance heaters to overheat. Or it might be a problem with the wiring within the motor. In this situation, it’s best to turn off your furnace before doing anything else. Then you can check the air filters. If everything looks fine there and you suspect a problem with the wiring, contact an HVAC professional. You should not attempt to repair an electrical problem yourself.


If there’s an acetone odor: You might have a refrigerant leak, and this can smell like acetone, or fingernail polish remover. Refrigerant leaks are sometimes a problem with older or improperly maintained systems. These not only reduce your system’s efficiency (and waste energy dollars), but can potential be hazardous because of its flammability. If you have this odor coming through your vents, schedule a system inspection. A trained technician will find the leak, repair it, and refill the refrigerant.


If there’s a urine odor: You likely have a pet infestation of some kind. Mice like to nest in and around equipment and ductwork when the weather gets cold. The solution is to find where they are living and have them cleaned out by a pest control specialist. Afterward, it’s a good idea to have your ducts cleaned, and install an air filtration system as well.


If there’s a rotten egg odor: It likely means you have a natural gas leak. Because natural gas is actually odorless, a harmless chemical, mercaptan, is added so you can detect the leak. If you ever smell a rotten egg odor coming from your vents, turn off your gas immediately and call an HVAC professional to come out and inspect your equipment right away. If you can, it’s best to leave the area until you have addressed the issue.


If there’s a stale odor: This probably means you have a ventilation issue. Nowadays with energy efficient windows, good insulation, and snugly installed doors, air gets trapped inside and stuffy or stale. The best thing to do is throw open the windows every now and again to let the fresh air from outside circulate throughout your house.


Keeping indoor air fresh and odor-free


When it comes to odors coming from your vents, less is more. You can usually keep the air in your home “invisible” to your nose by changing your air filters regularly and having your equipment regularly maintained. When an odor results from something else, you’ll want to contact a local trusted HVAC company like Drake Heating & Air to inspect the situation and fix the problem. Consider an annual maintenance contract to address small problems before they become big repairs.

Scroll To Top