Why Does My Air Conditioner Smell? Common Causes and How to Fix It

Trane air conditioner unit with a musty smell; common causes and fixes.
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Keeping your air conditioning system up and running is critical if you want to keep your Conejo Valley home cool and comfortable. Sometimes your AC will tell you something is wrong by the smells it emits. But what can cause these exhaust fumes or egg-like, musty, burning scents? And better yet, how can you eliminate these unpleasant odors?

After all, you installed your air conditioner to cool down your home, not stink it up with unpleasant AC smells, some of which might even be potentially dangerous. Here’s what you need to know about the seven common causes of the odor coming from your air conditioner and tips on eliminating them.

Air Conditioner Smells Like a Car’s Exhaust

Does the smell coming from your AC remind you of a car’s exhaust fumes? Your AC unit likely has a refrigerant line leak. If you’ve also noticed that your AC unit isn’t performing as efficiently, you’re definitely dealing with an AC refrigerant leak. Your refrigerant line may leak hazardous chemicals that are bad for the human body and the environment.

To prevent damage, quit searching “How to remove bad smell from split AC?” and call an expert immediately to investigate the issue. You can ventilate your home to eliminate the smell while waiting for HVAC repairs.

AC Smells Like Something Is on Fire

A faint whiff of burning that occurs when you first turn on your HVAC system is usually nothing serious. If it doesn’t dissipate by itself, and your AC smells like a more pungent burnt or gunpowder odor, you might be dealing with a short circuit, overheating motor, or loose sparking wiring.

If you’ve just turned on your AC and it’s emitting a faint burning smell, wait several minutes to see whether it dies down. For more pungent burning smells, shut off your AC immediately and contact an HVAC company for air conditioning repairs.

AC Smells biological growthy or Musty

If your home’s air conditioner smells musty or biological growthy, you’re possibly dealing with frozen evaporator coils or a clogged drain line. While frozen evaporator coils and clogged drain lines are usually the culprits, your AC might smell musty because of the following:

  • biological growth or mildew in your air ducts and vents
  • Clogged filters
  • Leaking air ducts
  • Dirty evaporator coils

If your AC’s smell reminds you of a musty, biological growthy basement, it’s time to schedule AC cleaning services. Don’t let musty AC smells prevent you from having a cool and comfortable home. Contact Conejo Valley Home Services for AC service in the Conejo Valley.

AC Smells Like Rotten Eggs or Gas

The dreaded rotten egg smell is the most worrying odor that your HVAC system can emit. An AC that smells like rotten eggs or sulfur almost always signals a natural gas leak in your house. Natural gas is a hazardous substance that can lead to fire or reduce oxygen levels in the bloodstream with severe, often fatal, consequences.

If you smell gas, switch off your gas supply immediately and call your gas company to report the leak and schedule an inspection.

AC Smells Like a Decaying Animal

What about an AC smell that’s not quite rotten eggs, but it’s something rotten? You could be dealing with a dead pest if you notice a putrid smell from your AC. Creatures such as birds, mice, and rats can crawl into your air ducts and die there, emitting a foul odor when they rot.

Start by calling pest control to remove dead animals, then contact your HVAC company to clean the ducts afterward to eliminate the smell permanently.

Air Conditioner Smells Like Chemicals

Your air conditioner should not smell like chemicals. It uses several fluids, but none of them should cause a noticeable odor. If your AC smells like sweet chemicals, you’re most likely dealing with a refrigerant leak. If it smells like formaldehyde, you probably have a cracked heat exchanger in your furnace and need to get it checked immediately. It’s best to contact an AC specialist to diagnose the source of the chemical smell. In the meantime, ventilate your home for your family’s safety.

AC Smells Like Gunpowder

Smelling gunpowder in your air conditioner? You’re likely dealing with a fried circuit board, power cord, fan, or compressor. The gunpowder AC smell is often caused by burning one of these components, so you should quickly turn off your air conditioner and contact your HVAC technician immediately.

If your AC smells musty after winter, the burning smell could be from the dust buildup burning off of your heat exchanger. You don’t need to worry if the smell disappears after a few minutes. However, if the smell persists after running the system for a while, consult a professional if you are unsure.

Air Conditioner Smells Like Cigarette Smoke

If you just bought your Conejo Valley home and are using the HVAC system for the first time, tobacco residue in the ducts and vents could create an odor of cigarette smoke in your home.

If you smell stale cigarette smoke when you turn on your air conditioner, start by changing the air filter, and if it doesn’t work, you need to schedule a professional cleaning and tune-up. Don’t let a minor problem turn into a large one that can cause damage to your HVAC system. With some HVAC maintenance, you can prevent the above smelly air conditioner issues.

Keep Your AC Clean and Safe

If you are experiencing an unusual smell when you turn on your AC system, don’t hesitate to call the experts at Conejo Valley Home Services to diagnose and fix the problem. We have been a locally owned and operated business since 1979, specializing in air conditioning, replacement, and fast AC repairs.

If you need fast and reliable air conditioning service, Conejo Valley Home Services can be at your side that same day. Contact us online or call (805) 499-0448 today!

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Matthew was very good, gave me good advice, did what he said he would and was polite and personable!
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Mary Krampach
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Service response was prompt. The electrician, Owen, is knowledgeable and thorough, addressing an unknown issue that saved us from a major loss had it not been resolved. I couldn’t be happier with the service I received at Conejo Services. I highly recommend them and have already done so to my neighbors.
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michael broomer
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I luckily found Conejo Plumbing on Yelp to service our tankless hot water heater, after my original plumber reneged on my lifetime contract. The plumber “Dier” was early for our appointment and after pleasantries was eager to solve the intermittent ignition issues we were experiencing. After an inspection it was noted that the igniter and flame rods had carbon and rust built up. Instead of soaking a customer and replacing our unit a simple service call got us back up and running. I can’t thank Conejo and “Dier” for the prompt service call and their professionalism. Suffice it to say Conejo will be my first call for plumbing issues and I look forward to seeing them in the future for HVAC calls as well. If you’re in need of a professional plumber I highly recommend Conejo as your first choice.
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BO XU
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I highly recommend the Conejo Company team, especially Craig McConnell, for their outstanding service! This was my second time working with Craig and once again, he exceeded my expectations. He was extremely professional, thorough, and responsible. He took the time to carefully inspect my air conditioning system, explain the issues clearly, and address the maintenance and repair problems efficiently. I truly appreciate his attention to detail and the pride he takes in his work. Craig is not only knowledgeable and skilled, but also honest, dependable, and genuinely committed to doing the job right. It is very reassuring to have a technician I can trust, especially when it comes to maintaining my home. I am very happy with the service I received and truly appreciate Craig’s hard work and professionalism. My experience with Conejo Company has been excellent, and I believe they have a team of technicians who are reliable, ethical, and dedicated to providing quality service. Thank you, Greg, and thank you to the entire Conejo Company team! I would definitely recommend you to family, friends, and anyone looking for a trustworthy and professional HVAC company.
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Great experience all around. From the sale to the installation. Thank you Anthony Nardizzi
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On time, no upsell and nice work
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Diane Douglas
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Carlos was very knowledgeable and helpful. He did the work in a timely manner.
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Vera Rabadi
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Very helpful Extremely polite Understanding I would recommend him
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Bill Wolf
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Estimator came out to quote repair of leak in roof. He found the problem and fixed it in a few minutes. He did not charge me for the service call. I will certainly use your firm in the future.
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Andrea Rubio
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Thank you Conejo Valley Heating and Air! David was amazing and I highly recommend!
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Jesse Chen
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Eric N was great! Very professional and communicative!
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Sandra Green
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At this moment in time, I am very pleased. My air conditioning is working right on the day that I needed it to work. Both workers Fernando and I think Andre were efficient , polite and thorough. The only reason I hesitate is that I had a bad experience with another HVAC company and I just watching to make sure that AC works as efficient as it should. I do thank you for your immediate responses and showing up on time.
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Nina G.
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I live in a condo and have been trying to figure out where a slow leak was stemming from. Craig McConnell was incredibly helpful, thorough and knowledgeable and helped me to rule out every possibility of it stemming from my unit. I now have what I need to move forward with my HOA. I couldn't have asked for more excellent service! Thank you!!
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Simone Vegas
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Been using Conejo Services since i bought my condo and never disappeared me. Fast professional reasonable..technician alwasy arrive early and super friendly.. and professional.
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jennifer sacks
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I had a great overall experience my air conditioning went out on one of the hottest days. I needed them to come right away not only the waive after hours fee but the technician Fernando was very helpful kind and knowledgeable. I am glad they have that membership discount because it cut the price to make it a little bit more affordable
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Mary Floyd
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James was wonderful. He suggested all the plumbing that needed to be replaced he showed me where it was why it needed to be replaced he was very clear professional.
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