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Why Does My Air Conditioner Smell Bad?

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While it's a common problem to have, it isn't normal to have a smelly air conditioner.

Typically, there is an underlying issue that needs your attention any time your AC smells bad. Just like unusual noises get your alarm bells ringing, funky smells should also be red flags to users.

If your air conditioner smells like it's burning or rotten eggs, you need an expert HVAC technician to conduct a thorough inspection and render a professional diagnosis.

Is It Normal for My Air Conditioning System to Produce Strange Smells?

A strange smell coming from your cooling or heating systems isn't normal, but it is common for poorly maintained air conditioners. Additionally, your air conditioning unit might need some repairs.

Reasons why your AC smells bad include:

  • Mold
  • Gas leaks
  • Dirty air filters
  • Clogged pipes
  • Poor indoor air quality
  • Electrical issues

Any one of the issues listed above requires professional attention. Users shouldn't dismantle and tinker around with their AC system.

Dirty Filters

If your air conditioner comes with accessible air filters, the most you should do is to dislodge them carefully and abide by its instruction manual on how to give it a thorough cleaning safely.

However, there are worse things to worry about besides dirty filters. More serious problems include a refrigerant leak, ruptured sewer vent pipe, and faulty wiring.

What Should I Do If My Air Conditioner Smells Like It's Burning

A burning smell reminiscent of gun powder, fireworks, or burnt hair may indicate electrical issues. A fried circuit board releases fumes into the entire system and may be distributed into your indoor air.

Wiring issues pose significant threats to your health. Simply inhaling electrical fumes can trigger allergies and asthma attacks. More worrisome respiratory problems may arise from prolonged or chronic exposure to hazardous fumes.

Additionally, the mismanagement or improper handling of coils and wires can cause severe injuries and damage the rest of your air conditioner. If sparks and buzzing sounds accompany a burning smell, make no attempts to inspect or resolve any possible problems.

Contact your local HVAC technician and fire department immediately.

Faint or Fading Burning Odor

However, if you are turning on your air conditioner for the first time in a long time, what smells like burning might be. Your unit burns off dust or particles collected on its components responsible for heat management.

It isn't unusual for your AC unit to release a slight burning smell when it's moving and shaking again for the first time, but it should go away just as quickly as it came.

Is There a Gas Leak

According to Portland's fire department, homeowners and building occupants often call in about gas leaks due to the stench of burning exhaust fumes from their air conditioner.

An HVAC system doesn't typically run on gas. Therefore, it has no links or storage of it anywhere. While a burning odor from your personal air conditioner or the building's central air conditioning systems should always be reported, it rarely entails a leak in your gas supply.

If it isn't coming from your air conditioning, you should call the gas company in charge of your residence's gas consumption.

Natural Gas Leak

There are plenty of reasons why your conditioned air is coming out funkier than you are accustomed to. However, you shouldn't write off any bad smell that's slightly acidic as harmless spoilage.

Sulfur from natural gas leaks may be what your nose is picking up. If it smells like stinky eggs, skunks, or burnt matches and it's coming from more areas than your air conditioner, there are high chances of a natural gas leak somewhere in your home.

It is dangerous to inhale in large amounts, causing nausea, headaches, disorientation, loss of consciousness, and possible carbon monoxide poisoning.

Open any natural ventilation (i.e., doors, windows), turn off all appliances, vacate immediately, and call your local emergency hotline.

If it's solely coming from your air conditioner and legitimately smells like rotting food, it's a less urgent matter that still needs your attention.

What if My Air Conditioner Smells Like Rotten Eggs?

Before blaming your air conditioner for the rotten egg smell, ensure you don't actually have any lying around your home or a backed-up sewer line releasing stenches and disrupting your perfectly air-conditioned home.

If a bad smell that reeks of rotten eggs comes from your central air conditioner, the problem may be hidden in its air ducts, and a simple duct cleaning should resolve the issue. A central air conditioner smells of rot or decomposition for those reasons exactly.

There might be a dead animal decomposing within its ductwork.

Air conditioning systems have tight filtration systems built-in, but an air filter is no match for scheming animals with opposable thumbs.

Rodents can somehow bypass blockages and crawl through air ducts and disrupt airflow. If they are smart enough to get in, they aren't always smart enough to get out.

When your AC vents reek of rotten eggs, hire a professional cleaning service.

A dead animal in your ducting releases foul stenches, and any liquids their body releases can lead to excess moisture in your systems which may eventually lead to mold.

Air Conditioner Smells Like a Musty Odor

If an air conditioner smells bad, often it's an issue you can deal with easily and quickly. However, the musty smells coming from your HVAC systems will need an expert examination.

Typically, an AC smells musty when there's mold growth somewhere within its draining system. Excess moisture or standing water that doesn't drain properly leads to mold and mildew.

The AC drain pan is where all the ambient humidity extracted by your AC unit settles. A build-up of pollutants and other foreign objects caught in the drain line prevents any liquids from draining properly, which clogs the drain pan. 

A clog in your condensate drain line must be dealt with immediately. It may lead to hazardous contamination and will require extensive repairs.

Clearing out a condensate line requires special HVAC equipment and comprehensive expertise to execute.

Alternatively, your air conditioner might be dealing with a case of Dirty Sock Syndrome.

Dirty Sock Syndrome

You can tell if dirty socks are in play if an air conditioner smells of moldy cheese and sweat when you turn it on the first time after keeping it off for a while.

An air conditioner smell that reminds you of your gym's men's locker room at the height of summer, the evaporator coils on your air handler are shrouded by dust, dirt, and other airborne particles. 

Evaporator coils play a large part in lowering indoor temperatures. The evaporator coil is responsible for extracting heat from indoors and diffusing refrigerants.

It deals with various fluids and is more susceptible to accumulating moisture.

A refrigerant leak or moisture build-up can cause a dirty evaporator coil. A leak in its refrigerants can sometimes smell like chemicals, but all that moisture will eventually produce mold spores.

It can quickly spread through the coil cabinet and contaminate your entire air conditioner.

It's best you contact your HVAC contractor or a reliable specialist for mold remediation.

How to Avoid Causing Unusual Air Conditioner Smells

It can be a drag when your air conditioner smells like something it shouldn't.

If you smoke indoors or improperly adjust your gas stove, you might be polluting your indoor environment.

Even lighting candles and spraying air fresheners can cause indoor pollution.

High volumes of cigarette smoke can quickly fill up an air filter, and your air conditioner can recycle the carbon monoxide it contains into your indoor air cycle.

You must have proper ventilation systems, both the natural and mechanical kinds. An excellent air exchange rate can do your home wonders.

A better airflow between doors, windows, chimneys, and exhaust fans helps reduce airborne contaminants from penetrating your air conditioning system's air vents.

If it isn't purified and filtered well-conditioner air, your air conditioning may negatively impact your Indoor Air Quality (IAQ).

What is Indoor Air Quality?

IAQ determines the quality of the air you are breathing in and around enclosed environments.

You can blame last night's poker game if your home smells like tobacco, butane, or overheating engines.

When smoke gets into your heating and cooling system's air vents, it can stay for prolonged periods and only worsen over time.

Without cleaning or changing your filtration systems, smoke can attract various pollutants. A breeding ground of multiple germs, microbes, and bacteria can add up to a compounded contamination and lead to numerous stenches.

You should take all the necessary preventive measures to ensure you aren't the one subconsciously causing mysterious air conditioner smells.

An HVAC Contractor You Can Trust

One of the best things you can do to prevent weird smells and other troubles is only to entrust all installations, repairs, and routine maintenance of your HVAC systems to a reliable heating and cooling company.

Sunset Heating & Cooling Electrical

The next time your air conditioner smells like something unusual, visit our company website.

You can book your appointment online or reach out to our experts immediately through our hotline.

Call (503) 500-5866

Available 24/7
In business since 1922

What Our Clients Say

Sunset went out of their way to help with my project and David was amazing. Great job and look forward to future projects.

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Roman did an awesome job. I had the trifecta, new AC unit ,furnace and hot water heater. Courteous, and competent service. I highly recommend Sunset Heating & Cooling.

-Charles E.

Eduardo provided excellent service when he repaired our AC. I felt his effort was over and above expected. Polite and professional at all times. Good job!

-William G.

Caring, professional and helpful. Thanks for making things happen quickly and getting my Dear friend's heating back up and running in such a quick manner. You went above and beyond for a family in need and that is very much appreciated. Thanks from the whole group!

-Kristina K.

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