10 Potential AC Smells To Be Aware Of

Has your air conditioner been smelling weird lately? Perhaps it sounds fine and it’s blowing cool air out, but a foul smell is never a good sign. Imagine you are hosting a dinner party on a hot summer evening. Your guests are about to arrive in the next few hours when all of a sudden, your air conditioner starts releasing a terrible smell. This can seriously put a damper on things. 

You need help immediately. We suggest switching your air conditioner off until you find the source of the problem and a suitable solution. Here are 10 smells to look out for and possible reasons for them. 

Rotten Eggs

If your air conditioner is releasing a sulfuric or rotten egg smell, there is a possibility that you have a gas leak. Gas is likely getting into your ductwork and being released into your home. This requires immediate attention as natural gas is a hazardous chemical that can cause a fire, explosion, or reduce the oxygen levels in your blood. Inhaling natural gas can have terrible effects on your health. If you are smelling this hazardous stench, you and your family are in imminent danger. You must turn off your gas supply and evacuate your home until a gas company can come to your house. It is unwise to switch your AC unit back on before fixing your gas leak. 


When your air conditioner starts to smell like a gym or smelly feet, it could mean that bacteria are growing in your air conditioning unit. This is usually a result of stagnant water, which is the prime breeding ground for bacteria and other microorganisms. While this sour smell is unpleasant, it’s not particularly hazardous. Your first line of defense will be changing your air filter. If the sour stench continues, give us a call, and we will clean your evaporator coil and drain pan since this is usually the cause of stagnant water. 


If you have noticed a musty smell coming from your air conditioning unit, there is likely moisture trapped in your ductwork. This leads to a growth of mold or mildew in the ducts. As a result, when air is released from your unit, that musty smell is released with it. You can start by checking your air filter, as this is usually the problem. Mold and dust may have clogged up your filter, creating that damp stench. If changing the filter has not made a difference, be sure to call your local HVAC company to clean your condensate line and duct work. 


It’s normal to smell a slight burning odor as you turn your AC unit on. However, when the burning smell is overpowering or similar to gunpowder, you should switch your AC unit off, since this is a fire hazard. Your AC unit’s motor may be overheating, or damaged wires are sparking. It is important to evacuate your home after switching your AC unit off. Call the fire department so they can assess the severity of the situation. Contact us immediately after the fire department, and we will provide a solution to your damaged air conditioner. 

Exhaust Fumes

If your electric-powered air conditioning unit smells like the exhaust fumes from a car, it means that there is a leak in your refrigerant line or motor. The smell of exhaust fumes should only ever be a result of burning fuel; it should never come from an electric-powered AC unit. We recommend that you don’t use your AC unit until you have called an AC repair company to fix the problem. 


If you smell a sweet odor that resembles antifreeze, it means that there is a refrigerant leak in your AC system. Freon or R-22 is the toxic refrigerant that is currently being phased out due to its harmful environmental and health effects. When you catch the sweet scent, freon may have been released into your home. Freon is toxic, so this can have detrimental effects on your health. You should stop using your air conditioner and open doors and windows to keep your home well-ventilated. Give Energy Pro Heating & Cooling a call today, so we can find the refrigerant leak and put a stop to it. 


If someone smokes cigarettes inside your home, your AC unit’s filter tends to absorb the stale smoke. The cigarette smoke runs through your AC unit and is released back into your home. Be sure to change your filter monthly if someone smokes inside your home. We also recommend an annual AC tune-up to clean the inner components of your AC system that may have absorbed the cigarette smoke. 


There is always a possibility that a skunk may have sprayed near your air conditioner’s condenser unit (the outdoor unit). This terrible smell will make its way through your ducts and be released into your home. Your immediate response would be to turn your AC unit off to prevent circulating the smell and to open windows to allow fresh air into your home. A professional HVAC company would then need to clean the ducts of your AC unit and clean your condenser to ensure that the smell does not come back into your home. 


If something smells rotten when your AC unit releases air, there is a possibility that an animal has made its way into your air conditioning system and died. Your air conditioner will spread the foul odor throughout your home, so it is a good idea to turn it off until someone can remove the animal carcasses from your AC system. Also, you should have your whole AC system cleaned out after this incident to ensure that the rotting smell does not stay behind. 

Nail Polish

If something smells similar to nail polish remover when you have your AC unit on, this is another sign that you have a refrigerant leak. It’s possible that your ductwork or AC coil can develop cracks and release refrigerant into your home. As we mentioned earlier, you should switch your AC unit off until you can have the leak repaired. If refrigerant should get into your respiratory system, it may cause difficulty breathing, headaches, and vomiting. 

The Importance of AC Tune-Ups 

Most foul smells are a result of a dirty air conditioning system. Over time, your AC unit collects dust, mold, pollen, and other debris that can cause unpleasant smells to be released into your home. This also causes your AC unit to work harder to overcome the obstacles, leading to more wear and tear and higher electricity bills. A dirty air conditioning system can cause several problems and even shorten the lifespan of your AC unit. 

It’s also important to change your air filter regularly. This can be done every second month unless you have pets or smoke indoors. In that case, your air filter should be changed monthly to ensure that your AC unit runs smoothly. If you don’t know how to change your AC filter, give us a call, and we will show you how. 

Be sure to schedule regular AC tune-ups with your local HVAC company in Portsmouth, VA, to ensure that your AC unit is clear of any obstructions. Regular AC maintenance will ensure that your AC unit is energy-efficient and effective at cooling your home down. 

Improve Your Indoor Air Quality

While some of these foul smells can’t be avoided, you can still improve the general condition of your indoor air. For instance, you can prevent mold and mildew from developing in your AC system and home by simply installing a dehumidifier. 

You can also rid your home of air pollutants by installing an air purification system. Air pollutants can cause severe health problems such as headaches, respiratory infections, and even an increased risk of lung cancer. You can eliminate these risks by regularly cleaning your AC unit and by installing devices that improve the condition of your indoor air. 

Energy Pro Heating & Cooling has a wide variety of indoor air quality services. Speak to one of our HVAC technicians about improving your indoor air so that you can increase the safety of your home for you and your family. 

Get the Best HVAC Services in Portsmouth, VA

So, if your air conditioner smells like rotten eggs or some other foul stench, contact Energy Pro Heating & Cooling today to find a solution and rid your home of any gross odors. You should not have to put up with any unpleasant smell in your home. Some of these smells are severe health hazards and should be taken care of immediately. Others, while not harmful, can just be unbearable to endure. Whatever the case may be, you paid good money for your HVAC system and deserve pristine air quality in your home. 

Do not settle for anything less than the best. Contact Energy Pro Heating & Cooling for the best HVAC services in Portsmouth, VA. As your local HV AC company, we’re dedicated to ensuring that your home is comfortable and safe for the whole family. 

July 25th, 2022 | Heating and Cooling