May 4, 2021
Dirty AC Unit in San Antonio, Texas

The air conditioning unit is one of the most-used appliances in many households, and it can make your home uncomfortable when it’s not functioning properly. However, it gives off various signals when it is malfunctioning. One of the most common signs is strange sounds coming from the unit, but awful smells are also a common signal, and they are pretty hard to ignore.

If your air conditioning system begins to emit unpleasant smells, it means your unit is either too dirty or malfunctioning in a way. Some of these odors are harmless and only indicate your unit needs servicing while others indicate that you need the attention of an AC service immediately. Below is a list of the most common AC odors, the causes, and how to resolve them.

1. Musty Odor

A dingy and stale AC smell is one of the common and awful odors that many homeowners experience. The primary cause of the musty odors is water accumulation in the AC drip lines or drip pan. If you have a ducted system, water can also collect in the ducts, leading to mildew or fungus growth. You may even get some visible signs in the indoor ductless system in case of leaks, like some water dripping down the wall.

The other reason for a musty odor can be dirty or clogged filters. If you reside in a region with hot, humid weather and switch on your AC unit after a long time, moisture may accumulate in the air filters. With time, this excess moisture can foster mold growth. Mildew and mold growth in your air conditioning unit can significantly compromise your air quality, causing you to experience symptoms such as allergic reactions and headaches.

If there are leaks in your unit, have your AC technician inspect and fix them to prevent more serious problems. To prevent microbial growth or eliminate the existing growths, you need to invest in annual maintenance for your unit. If there is mold growth in your ducts, you will need a professional duct cleaning service to clean your ducts and AC lines.

2. Electrical or Burning Smells

An air conditioning unit has many inbuilt electrical components, including fans, compressors, circuit boards, and power wires. A burning odor may indicate a mechanical issue with your AC’s compressor or fan, component failure, or wiring problems. It may also mean that one or more components are burning. In such a case, turn your AC unit off immediately and contact your local HVAC technician for a solution.

The other common reason for a burning smell is dust accumulation in your AC after a long duration of inactivity. Once you turn on the unit after a long period, this dust will burn off and emit a foul odor. The good news is that this problem is temporary and you don’t have to worry about it. Give the unit around 20 to 30 minutes to see if the smell will clear on its own. If the odor remains or becomes highly intense, you need to contact your AC expert immediately.

3. Rotten Eggs Odor

A rotten AC odor may be a result of dead critters or rodents stuck in your air conditioner. This smell is distinct, and you cannot mistake it for anything else. Insects and birds can take refuge or nest in your ductwork during harsh climatic conditions and get trapped in the AC unit.

With time, these decomposing rodents and pests will emit foul smells. Once you turn on your AC system, it can produce an unpleasant odor in your home. Besides, these stuck and dying animals may also damage some components within the air conditioning unit.

To solve this problem, locate the duct from where the awful stench is coming from. Using a screwdriver, remove the cover and carefully remove the animal’s carcass. Once removed, wipe the entire area clean and ensure it is dry before covering it. Next, have an AC service check your ducts to make sure nothing is damaged. Also, seal all points of entry by pest-proofing your AC system to avoid such nasty scenarios.

4. Dirty Socks Odor

If you turn your AC system on and your home begins to smell like some dirty socks, it’s an indication that the unit’s evaporator coils need a thorough cleaning. Your unit’s evaporator coils can develop some microbial growth with time, making your residence smell like it is your laundry day. Call your AC expert to clean the evaporator coils once you smell this odor. If you can withstand the unpleasant odor, there is no harm in running the air conditioning unit until the AC technician arrives.

5. Cigarette Smoke Smell

If one of your family members smokes at home, chances are that your air conditioning unit might end up smelling like old cigarette smoke. That’s because the unit’s evaporator coils and air filters absorb the smell from cigarettes. Once you turn on your AC unit, the embedded cigarette particles loosen up and are sent back to your house through the vents of the AC, creating an unfriendly atmosphere.

Awful cigarette odors can cause health complications such as headaches and allergic reactions. However, the solution to this problem is simple. To eliminate the stale cigarette odor from your air conditioning vents, ensure you change your filters at least once every 30 days and regularly clean your air conditioning unit. Smoking outdoors in a designated area can also prevent the tobacco smoke smell from spreading in your home.

6. Gas Odor

A gas smell indicates a gas leak within your air conditioning unit. Generally, natural gas doesn’t smell, but gas and utility distributors usually add some methyl mercaptan to the gas to give it a distinctive odor. This way, you can easily detect gas leakage and prevent physical harm and property damage from the leaks.

If your air conditioning unit produces an odor that smells like skunk sprays, you will not be mistaken. That indicates that you are dealing with a gas leak, and the gas is entering your ductwork. Once you notice a gas odor in your residence, turn your gas supply off immediately and contact your HVAC service. The professional will help you locate the leaks and make the necessary repairs.

7. Exhaust Fumes Smell

A smell of exhaust fumes in your home indicates that there’s a fluid leakage in your AC unit. In many cases, the fluid might be leaking on some warm part of the unit, causing the fluid to steam. In this case, you need to contact an AC service to inspect your system. To avoid damaging the unit or causing further problems, avoid running your AC unit until a professional examines it.

Final Words

Unpleasant AC odors are usually indicators of problems within your air conditioner, meaning you should not ignore them. So, if you notice any of the awful smells above when running your AC unit, then it’s time to give an HVAC expert from Beyer Air Conditioning & Heating a call. Our team of professionals will inspect your AC system and solve the problem to eliminate the unpleasant odors and restore your home’s comfort.

We also offer air quality services, air duct repairs, and ductless AC services in San Antonio, TX, and the surrounding area. Our licensed experts are specialists in heating and cooling installations, replacements, servicing, and repairs. Contact us now for any AC-related services to ensure your air conditioning system is ready for all the seasons ahead.

company icon