Central air conditioning systems can help improve your home's indoor air quality, but they don't typically have much of an impact on odors. A standard HVAC filter can remove particulates from the air in your house, but an additional charcoal filter is usually needed to remove smells. However, issues with your air conditioning can sometimes create unpleasant odors.

A poor-smelling air conditioning system can sometimes mean you need to replace your old filter, but there are certain situations where unpleasant odors can be more than a minor inconvenience. If you notice these three smelly situations, you may want an HVAC contractor to examine your system for more serious trouble.

1. Persistent Moldy Smells

Moldy smells in most cases indicate excessive moisture. When your air conditioning system is in working order, it should remove humidity from your home. Generally, the air coming from your home's vents should be drier than the air elsewhere. If this air instead feels cold, damp, and clammy, or you can smell musty odors whenever your system turns on, it usually means trouble is brewing.

Persistent moldy smells can often result from excess moisture accumulating on the evaporator coil. This situation can occur if a refrigerant leak causes the evaporator coils to freeze, or a clog in your condensate drain prevents condensation from flowing freely. In either case, you'll need an HVAC technician to examine the system before to avoid potentially causing more damage.

2. Blasts of Warm, Smelly Air

Your air conditioning system works in cycles, with the main house blower turning on alongside the AC compressor. These two components must work in sync because the blower motor needs to deliver warm return air to the evaporator coil and distribute cold air to the rooms in your home. If the blower runs without the compressor, your vents will only produce warm and humid air.

If you notice that you frequently get blasts of warm, smelly air before your air conditioner shuts off, it may be a warning that your compressor is shutting down before the blower. This symptom may mean a problem is causing your compressor's safety to shut it down before the cycle completes. Since short cycling can be inefficient and damaging, you shouldn't ignore this issue for long.

3. Burning Odors

You may sometimes smell a brief burning odor when using your furnace for the first time each winter. Dust can accumulate on the heat exchanger over the summer, burning off on the first few cold days of winter. However, your air conditioner should never produce similar odors. A noticeable burning smell from your vents is almost always a problem.

First, ensure that your vents aren't picking up and distributing a smell from elsewhere in your home. If not, the problem may be due to your HVAC system's blower motor overheating and failing. You may also hear grinding or screeching noises, which are further indications that your blower motor is approaching the end of its lifespan.

To learn more about air conditioning repair, contact a professional near you.