May 24, 2021

An air conditioning unit’s prime purpose is to maintain comfortable indoor temperatures even during hot summer months. If you turn on your AC and it blows awful smells, this means that your unit has some underlying issues that require immediate attention. It might be challenging to determine the exact source of the smell, especially if you aren’t conversant with how an AC operates. Here are nine unpleasant and even potentially dangerous odors that can emanate from your AC.

1. Burning Electrical Odor

When you switch on your AC after having it off for an extended period, it might emit burning smells within the first few minutes. During periods of inactivity, the AC may accumulate dust, and when the unit heat-ups, it can produce a burning smell. The odor should dissipate on its own after a few minutes. If the problem persists, you might need to call a professional to assess the issue and make the necessary repairs.

The air conditioning unit contains various electrical components. If the AC smells like something is on fire, it probably means that your unit’s parts are overheating. This is a serious issue, and you shouldn’t attempt to fix it on your own. Immediately, shut off your system at the breaker box, and seek professional assistance. Other times, electrical odors can result from some mechanical problems with your AC fan or compressor. Planning for regular HVAC maintenance can help prevent such issues.

2. Rotten Egg Smell

The smell of rotten eggs from your AC signifies leaking gas. Though the natural gas used in air conditioners is colorless and odorless, manufacturers combine it with Mercaptan, giving it the stinky smell of rotten eggs to notify the user of a gas leak. Prolonged exposure to this gas can lead to lung irritations, difficulty breathing, severe headaches, confusion, loss of consciousness and mental fatigue.

Once you notice signs of a gas leak, switch off all electrically operated equipment, put out any flames and open the windows and doors to avoid an explosion or fire. Leave the house immediately, and contact your HVAC company to fix the issue.

3. Chemical-Like Smells

If your AC produces an odor similar to paint thinner or nail polish, it could emanate from fluids used within your unit. It signifies AC malfunction, and you should call your HVAC technician for a proper diagnosis. At other times, placing open paint containers near your system can result in recirculation of odors throughout the house. The AC may pick up the smells from inefficiently sealed containers and force the scent through the rest of the rooms. Look for all paint and chemical containers in your house, and store them appropriately to get rid of such smells.

4. Exhaust Fumes

Fluid leaks from vital AC components like the engine can cause the production of exhaust fumes. If your AC is faulty, it can emit a large volume of toxic gases. These fumes are dangerous. They deplete oxygen in your blood when inhaled and can cause an array of health issues. Once your AC starts producing exhaust-like fumes, have a technician inspect it to diagnose and fix the problem.

5. Musty Smells

A musty smell signifies the presence of mold and mildew within your unit. Excess moisture in the vents or air ducts encourages the growth of biological contaminants. If you reside in high-humidity regions and fail to turn on your AC for some time, the filters may accumulate dust and moisture, causing mold issues. When the air filters clog, they limit airflow, which causes water to collect on the evaporator coil. The moist conditions create an ideal environment for the growth of mildew and mold.

An inefficient drain pan and blocked condensate line can also encourage mold growth. Your vents will then begin to release musty smells. This could trigger asthma attacks and allergic symptoms, especially for people with compromised immunity.

The only solution for this issue is to find where the mold is and clean it up. If the problem persists, have a technician thoroughly clean the unit and fix any underlying problem to avoid mold recurrence.

Be aware that an oversized AC unit can also cause high humidity issues. It cycles on and off quickly, so it doesn’t efficiently draw out moisture from your indoor air. Have a technician determine the right unit size for your house by considering the square footage, number of occupants, local climate, insulation level and ceiling height.

6. Gunpowder Odor

The most common cause of a gunpowder odor from your AC is a shorted-out circuit board or fan motor. Exposure to these fumes can negatively affect your health. When you detect such smells, switch off your unit and have a professional perform an inspection before running the system again.

7. Rotten Carcass Smell

In extreme weather conditions, critters, bugs and birds tend to seek refuge in the AC compartments. Unfortunately, some might get stuck inside and die, thereby emitting unpleasant odors. Once you turn on your AC, it would then circulate a foul stench throughout the house. The only solution is to have the dead animals removed and the affected parts thoroughly cleaned. Getting rid of dead animals is an unpleasant experience that is best left to qualified technicians.

8. Strong Nicotine Odor

If your AC circulates air that smells like cigarette smoke, chances are that there is somebody smoking in your house. The filter and evaporator coil absorb these fumes, and whenever you turn on the AC, it recirculates a strong nicotine odor throughout the residence. These smells can cause headaches and allergic reactions.

Also, if you live in an apartment with interconnected plumbing or ductwork and your neighbor smokes in the house, the smells may seep into your indoor space. In such a case, you will need to change your air filters more often. Call an HVAC professional to clean and sanitize your unit. Also, encourage your home occupants to smoke outside.

9. Stinky Feet Smell

Sometimes, your AC may emit smells that are similar to dirty socks. This is a sign of bacterial growth in the condenser coil. Dirt accumulation and the presence of water in the drain pan allow bacteria to proliferate. Professional cleaning and sanitization of the coils can help resolve this issue.

Bottom Line

When your air conditioner emits unusual smells, it signifies failure of components or the presence of contaminants that lower indoor air quality. Trying to mask such odors with scented candles or aerosol spray will only make the air quality worse. Routine AC maintenance is the best way to protect your unit from unforeseen issues like odor emissions. While you can do some minor fixes to eliminate nasty smells from your AC, technical repair tasks require a professional approach. An experienced technician can address the root cause of the foul smell and clean or replace AC parts to restore the natural scent of your house.

If your AC emits any of the odors mentioned, contact Beltway Air Conditioning & Heating. We have a team of specialists committed to providing your family with a healthier living environment. Our company also offers house humidifier and whole-house air purifier installation services. We install, maintain and repair furnaces, heat pumps and air conditioners across Annapolis, MD, and the nearby regions. Call us today to schedule an appointment and try out any of our services.

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