How To Stop Musty Smell From Air Conditioner

There’s nothing quite like escaping the sweltering hot weather and unwinding in your air-conditioned house. However, if you detect a weird, musty odor, you must act quickly. 

What does a musty odor from your air conditioning unit indicate? Does that mean you may have to shell out money for repairs? 

If your air conditioner smells musty, the most common culprit is a buildup of water in the drainage pan or drip pipes, which can lead to the growth of bacteria or mold. There are various ways you can get rid of these, such as cleaning or installing filters.

In this article, we’ll go through some of the most prevalent causes of why your air conditioning system may be emitting a foul odor and what you can do about it. 

Why are Strange Smells an Issue?

Whether the odors coming from your duct stink like rotten eggs, dirty socks, or fungus, all of them point to a problem with your air conditioner. As dirt accumulated in your AC unit starts burning off, it could generate a burning odor at the outset of the heating or cooling season. 

You may have a deceased animal or gas leak in your ducts if you smell rotting eggs. A moldy or dirty sock smell indicates that you may have a fungal problem. 

The presence of impurities in your AC system can also make your air conditioner smell musty. Your unit is a seedbed for germs since it is damp and dark.

It signifies that your air conditioner is spewing harmful mold spores throughout your home. These germs can create serious health problems, especially if someone in your family has allergies. You should never ignore peculiar odors emanating from your home’s HVAC unit.

Why Does My AC Smell Musty? 

Musty smells are often caused by the growth of fungi, like, for example, black mold. That is why your air conditioner can also emit such odors. 

Another explanation is that the coils in your air conditioner have begun to rust. In any instance, an accumulation of excess moisture in your air conditioning unit is probable, and musty smells are a red flag that this is the issue.

Reasons Why Your AC Smells Musty

While you wait on your air conditioner expert, investigate to help them pinpoint the source of the problem. That will expedite the procedure and guarantee that your HVAC unit is serviced correctly in a short while and that your home smells pleasant again. 

Here are five frequent causes of a musty odor in air conditioners and where you can check to see if this is the case.

The Drain Pan is Overflowing

Water drops drip into the drain pan when your AC eliminates humid air from your house. Because this component of your AC unit is susceptible to mechanical damage, its effectiveness will diminish over time. 

Whenever the unit is operating, an inefficient drain pan collects mold, which can make your air conditioner smell musty. Have your local HVAC technician replace the drip pan with a fresh one to get rid of the smell. The drip pan is placed just beneath the evaporator coils of your unit.

Evaporator Coils That Have Been Frozen 

Your air conditioning system takes warm air, cools it, and circulates it via return vents. However, this process requires free circulation; therefore, you should clean air filters regularly. 

Since dust accumulation obstructs the airflow, water drops from the moist indoor air collect on the evaporator coils. When the refrigerant in the AC system cools the air, these droplets will solidify. 

Your air conditioner expert will have to let the condenser coil defrost and replace the filters to restore optimal airflow. The evaporator coils are found inside or around the air handler; that is where your unit’s blower fan is placed.

Moisture Buildup in Vents or Air Ducts 

Rising moisture levels or a drain leakage cause excess moisture to build inside your system’s condensate line, valves, and air ducts. If you notice a musty odor as soon as you switch on the air conditioner, mold and mildew may have found their way inside your air ducts. 

Mold inhalation has been linked to upper respiratory problems, so contact a professional HVAC expert immediately. 

To permanently eliminate the unpleasant odor, you’ll need to clean and mend your vents and air ducts. Your ducting is connected to your home’s vents. Because some ducting is hidden in the ceiling or a basement, a specialist will need to examine it to resolve the mold problem.

Blocking of the Drain Line

The condensate line is a tiny PVC pipe positioned beside the condenser unit. The condenser unit is a component of your AC placed outside your house. Its function is to drain the pan’s water into your landscape or a rain gutter.

Due to its tiny size, the condensate drain line is perhaps a very common breeding ground for mold, fungus, and gunk. It causes clogs in your pipes, as well as musty odors in your residence.

Incorrect AC Size for Your Home

Your air conditioning system must be the appropriate size for your house to function correctly. If it’s too big, the air is circulated too fast, resulting in a shortage of dehumidification as well as a rise in humidity. It will repeatedly switch on and off if it is too small, resulting in early failure. 

Consult your HVAC expert to see if your air conditioner is the right size. More than your house’s square footage goes into determining the size of your AC unit. Your service specialist will also consider the number of individuals who live there, the kind of insulation in your house, and your requirements depending on the climate in your area.

How to Stop the Musty Smell Coming from the Air Conditioner? 

Turn off your cooling system and gently unscrew the access panel to uncover the coil. Using a delicate brush attachment, carefully suction the coils and fins. In case a fin is twisted, straighten it using a screwdriver. Employing a mix of 10 parts of water to 1 part of bleach, spritz the coils and delicately wipe them clean.

Ways to Remove Musty Smell from an Air Conditioner

Let us examine a few techniques of getting rid of germs and fungus in your air conditioning unit now that you know what causes it.

1. Turning Off the Power to the Unit 

When servicing a home air conditioning system, it’s better to switch it off at the source, as with any form of upkeep. There will be a designated shut-off point, and this is required to prevent significant physical harm.

2. Cleaning or Changing the Air Filter(s) 

The air filter is always the first item you examine for almost any AC issue, as replacing or cleaning the air filter will help resolve many AC issues. Furthermore, if a clogged air filter is the source of your issues, it should be evident: the clogged filter will smell strongly of mold and have visible fungal growth. 

If this is the scenario, remove it immediately. In an hour or two, you will notice a difference in the scent emanating from your air vents. Based on the kind and grade of filter, most homes must replace their air filters every one to six months. 

3. Thoroughly Cleaning the Evaporator Coils 

After changing the filters, use a foamy coil cleaning solution to cleanse each evaporator coil. These can frequently become dirty during regular functioning, causing a strange smell and lowering effectiveness.

4. Cleansing the Drain Line 

The condensate drain line is for draining moisture from your air conditioner. If it becomes obstructed, moisture will accumulate over time, leading to fungus and rust. You’ll notice water collecting around your cooling system if your condensate drain line is blocked up. If this is the case, you must unblock the drain line to remove odor avoid mold growth, and harm the device in the future.

5. Installing Duct Filter Pads in the Vents for Controlling the Odor

If the bad smell wasn’t emanating from the air conditioner, it might have come from anywhere in the ductwork. Unfortunately, finding the problem without a snaking camera network may be challenging. Employing duct filter pads is the next effective option for eradicating the odor. 

These hypoallergenic filter pads can be found at most retail establishments and are designed to fit all kinds of horizontal and vertical ducts. Remove the duct vent cover and insert the filter pad into the grates. Reinstall the cover and allow the filter to catch the errant granules.

6. Seeking Professional Help

If none of the preceding solutions have helped, you can try cleansing your ventilation tubes more thoroughly yourself. If this option doesn’t work too, or if the odor appears to be emanating from a dead animal, you’ll need to hire an air duct cleaning agency. Remember to schedule routine inspections for your air conditioner to avoid musty odors in your house.

Benefits of Routine AC Maintenance

As summer approaches, many individuals have started routinely turning on their air conditioners. Therefore, it is essential to have your AC system tested and repaired frequently, be it new or a ‘vintage’ that has provided dependable services for numerous years.

Improves the Quality of the Air 

Dust and dirt granules that accumulate within the AC unit are removed by a highly skilled expert acquainted with your system. If these fine particles build up, they could enter your duct system and disseminate throughout your house. 

Provides a Higher Level of Efficiency 

The servicing procedure includes cleaning and inspection of fans, cooling coils, the drain line, and other essential unit sections. Cleaner coils are likely to produce cooler temperatures while conserving more power than coils not maintained at least once a year. So as the weather warms up, reduce your bills and keep cooler!

Extends the Lifespan of Your AC Unit

Regular maintenance ensures that your system performs at its best throughout its lifespan. It is particularly true in places where winters can be bitterly cold and summers can be scorching and steamy. Routine maintenance aids in the safe and smooth operation of one of your significant financial investments. 

Other Air Conditioner Smells You Should Be Aware of

Foul AC odors are one of the most important issues that consumers face. However, you can’t be sure if the bad smell is coming from your AC unit, what sort of odor indicates which issue, or what Freon smells like.

So, before you can fix the issues, you must first understand them! We’ve gone over each type of odor you can encounter if you have an air conditioner in great detail.

AC Smelling Like a Car’s Exhaust

Your HVAC system uses several substances that, when overheated, can smell like vehicle emissions. This odor from an air conditioner indicates a leakage in the refrigerant line. 

If your air conditioner emits a chemical-like odor, you should have it checked by an expert as soon as possible. A Freon leak might be dangerous, but it’s easy to fix with the help of a professional HVAC technician.

AC Smelling like Something Burning

Electrical wires, compressors, a drain line, circuit boards, and fans are just a few of the electrical parts in your air conditioner. If your air conditioner smells like burning plastics or gunpowder, one or more of these elements are likely on fire. In this situation, turn off your air conditioner right away and seek advice from a local expert.

AC Smelling like Rotten Eggs

Dead rats or creatures trapped in the air conditioner frequently cause a nasty or rancid odor. It is a solid and distinctive odor that you can’t confuse for anything else. Flying insects and birds can build nests or take shelter in your ductwork, causing them to become trapped.

These dying creatures create foul odors over time. When you switch on your air conditioning unit, it might emit a nasty odor into your house.

AC Smelling like Gas

The most problematic air conditioner odor on our radar is this one. It most commonly signals a gas leak inside the network, particularly methyl mercaptan. Natural gas has no odor, so gas companies add methyl mercaptan to the unique smell. This guarantees that any gas leakage is detected as soon as possible, preventing any significant harm.

AC Smelling like Vinegar

If the air exiting your air conditioning unit smells acidic, like vinegar, the issue could be caused by an ozone-emitting electric motor. Extra moisture on the coils, a faulty filter, a blocked condensate pan, or mold in the ducting is all possibilities.

AC Smelling like Chemicals 

The refrigerant in your air conditioner is used to extract warmth from the warm air in your house. The refrigerant passes via copper coils that are closed. These copper coils might shatter over time, allowing refrigerants to spill. The refrigerant, which has a slightly pleasant chloroform odor, could be the source of the stench you’re detecting.

AC Smells Musty FAQs 

What causes a musty smell when my AC turns on? 

In essence, a musty smell coming from your AC suggests bacterial development on the drainage, evaporator coil, or drain pan of your air conditioner. Because your evaporator coil is damp, mold and fungus can thrive, resulting in an awful, musty odor.

Can I use vinegar to clean the air conditioner coils? 

Cleaning an evaporator coil with vinegar and water is common at home. On the other hand, vinegar is generally only helpful against lesser dirt accumulation. However, you can maintain your coils by combining white vinegar and water in a spray bottle and squirting the solution onto the coils.

Why does my AC smell musty even when it’s not heated up?  

A filthy evaporator coil or obstructed condensate drain pan is the most common cause of a musty smell coming from your air conditioner. If it is just the former, you can aid by cleaning dirt and debris out of your condenser using a hose. However, for a thorough cleaning, you can consider professional servicing.

Why does my car AC emit a musty smell? 

Dust, dirt, and junk accumulation in the under-hood air intake exhaust retain moisture inside and on the surface of the evaporator, causing these odors. In that damp, trapped waste, all kinds of terrible bacteria can fester and thrive.

How to stop a musty smell from a central air conditioner?  

If your central air conditioner smells musty, it’s because there’s mold, fungus, filth, or other growth within. When looking for the cause of the given problem, there are two crucial locations. The first is the HVAC unit, which is positioned outside the house. The second is the air handler, placed somewhere within the home.

Why does my split system air conditioner smell musty? 

A musty odor coming from a split air conditioner is almost always an indication of mold growth-a smell described as dirty or like stale socks. Your split AC may, in certain situations, smell like pee. That is due to the mycotoxins produced by bacterial proliferation.

How to get rid of the musty smell in AC vents?  

Elevated humidity levels or a drain leakage cause extra moisture to build up within ventilation ducts and air vents. You can clear the duct with a vacuum or hire a specialist to do it for you.

Wrapping Up 

Your air conditioning system is a crucial part of your home, and as such, you must keep it in good working order. Unfortunately, many reasons can make your air conditioner smell not-so-fresh. In this article, we’ve gone over some of the most common causes for foul smells coming from your air conditioning system. 

If your system emits a foul odor, it’s essential to get it checked by an HVAC technician. They’ll determine the exact cause of the odor and make the required repairs.