What’s that awful smell? When your central air conditioner smells bad, it’s never a good sign, and definitely not good for your health. Even worse, some smells are toxic, and require urgent attention.

The air conditioning unit in your home is one of the most-used appliances, and it’s inconvenient and uncomfortable when it isn’t working properly. Fortunately, it’s pretty good about giving signs when it is in need of service. One of the key things that many homeowners notice is bad aromas coming from the unit. An odor problem doesn’t necessarily mean that the repair will be expensive. It could be a dirty air filter or condensation which has created mold in the unit.

Potentially toxic smells coming from your air conditioning unit include…

1.   Burning/Electrical Odors – Electrical odors could indicate a mechanical problem with your AC fan or compressor, wiring issues, or electrical component failure. Made with a variety of metals and chemicals, prolonged exposure to these fumes is not healthy. The first few times the unit kicks on, it may emit a burning odor that can smell electrical and dusty, give it 20 to 30 minutes and see if the smell dissipates. If it does, it probably was just the dust burning off. If it continues, contact a professional HVAC technician to check out the problem and make repairs. An electrical odor typically is a problem within the motor or the wiring. Attempting to fix either of these items can result in severe injuries.

  2. Gunpowder Smell – Cousin to ‘burning smells,’ a distinctive, gunpowder-like aroma may also be due to a fried circuit board or fan motor.  With such smells posing similar dangers, it’s always a good idea to call for a professional inspection before running your system again.

3. Rotten Eggs – Provided there aren’t any rotten eggs in your home, the smell of rotten eggs or sulfur most likely indicates a natural gas leak.  Although on its own, natural gas is odorless, most utility providers add the aroma to alert people of a dangerous leak. Don’t take this lightly. If you smell a rotten-egg-like odor in your home, natural gas is likely the culprit, and immediate inspection is a must. While low level exposure is not hazardous to your health, high levels reduce oxygen in the blood, and can lead to loss of consciousness and death. Gas is also highly flammable and explosive, resulting in dozens of deaths each year. If you notice this smell, open the windows to your home right away, get out of the house immediately, then call the gas company.

4. Exhaust Fumes – Even in systems not powered by gas, exhaust fumes can still result if fluids leak from essential components. To avoid a dangerous situation, have your system professionally assessed. Burning oil and other fluids can release large amounts of toxic gases, different in chemical makeup than in natural, liquid form. These particulates can be hazardous to your health, depleting oxygen and resulting in an array of health issues.

5. Chemical Aroma – If you think your air conditioner smells like paint thinner, formaldehyde or other chemicals, it’s always better being safe than sorry. Many fluids are used within your air conditioning system that could result in an assortment of chemical odors with system malfunction, making prompt AC repair advisable.

6.   Musty or Moldy Smell – A smell like mildew or mold is probably the most common symptom of central HVAC systems. When the air conditioning is running, there is a lot of condensation within the unit. When the moisture doesn’t drain properly, it can escape into the ducts and create mold. Finding where the mold buildup is and getting it cleaned up will solve the problem. An HVAC repair technician has the knowledge to handle the problem and ensure that it doesn’t occur again.  Note: Mold and mildew smells are not serious problems with the unit, but the poor air quality does increase the risk of respiratory infections in both children and adults. You can still use the unit while you’re waiting for repairs, but you shouldn’t put it off for the sake of your family’s health.

 

When troubleshooting the smell, use your other senses as well. Listen for clunking or knocking. Look for excess water on the ground or other liquids which don’t belong. Many times, the smells are not dangerous, just indicative that your system needs service. However, some smells, like rotten eggs or gas are more serious. If you are experiencing an electrical, burning odor, or gas smell, turn off the unit and call your HVAC technician right away. An HVAC repair technician can diagnose the problem and recommend solutions.

Have your central HVAC system inspected annually by Miller’s Heating & Air to look for faulty wiring, loose or worn belts, and general wear on the unit. By having an annual service, you have peace of mind that you’ve done what you can to make sure your central HVAC unit is ready for the seasons ahead.