Fast read
If your air conditioner has a musty smell, it’s likely because of mold or mildew growth. This can happen in the ducts, evaporator coils, or drain pan, where moisture collects.
To fix this, check for moisture in the ducts, ensure the drain pan isn’t overflowing, and see if the condensate line is blocked. Also, verify that your AC unit is the right size for your home and that the evaporator coils aren’t frozen. If the smell persists, it’s best to contact an HVAC professional to inspect and clean the system to prevent further issues.
Why does my air conditioner smell musty?
A musty smell from your air conditioner suggests bacterial development on the drain, evaporator coil, or drip pan or drain line of your air conditioner (AC). As your evaporator coil is in a dark and damp environment, mould and mildew can thrive, resulting in an unpleasant, musty odour. Below are the procedures to figure out what’s causing the musty air conditioner smell and how to cure it, including:
- Examine your ducts and vents for any excessive moisture.
- Check to see whether your air conditioner’s drain pan is full.
- Check to see if your air conditioner is the proper size for your home.
- Examine the evaporator coils for any signs of freezing.
- Determine whether your condensate line is blocked.
The reasons are as follows
Since air from your air conditioner vents shouldn’t have an odor, contact a professional Heating, Ventilation, and Air Conditioning (HVAC) firm if you notice a musty smell after lowering the thermostat.
Please keep reading below which highlights why you should act quickly if you notice a peculiar odour and five frequent reasons why your air conditioner has a musty smell.
Moisture in ducts or vents
High humidity levels or a drainage leak cause extra moisture to build inside air ducts and vents. If you notice a musty odour as soon as you switch on the air conditioner, mould and mildew may have found their way into your ducting.
Mould exposure can lead to upper respiratory problems, so contact a skilled HVAC technician at once. To get rid of musty scents for good, you’ll need to clean and repair your ducts and vents.
Where to Look – Your ducts are connected to your home’s vents. As some ductwork is hidden in the ceiling or in a crawlspace, a specialist will need to inspect to ensure the mould problem isn’t severe.
The size of your Air Conditioner is incorrect for your home
Your air conditioning unit must be the proper size for your home in order to function properly. If it’s too large in size, the air circulates too rapidly, resulting in a lack of dehumidification and an increase in moisture. It will repeatedly switch on and off as it’s too tiny, resulting in early failure.
Check with your HVAC professional to see if your air conditioner is the right size. The square footage of your home has nothing to do with the size of your HVAC unit. Your service specialist will also take into account the number of people who reside there, the kind of insulation in your home, and your demands depending on the climate in your area.
Where to Look – Have your system evaluated by a service HVAC professional.
The drain pan is overflowing
As your air conditioner unit removes humid air from your home, water droplets collect in the drip or drain pan. Over time, the constant exposure to wear and tear reduces the efficiency of this HVAC component.
When the unit is operating, an inefficient drip pan collects mould, which generates the odour in our house. To get rid of this stink, have your local HVAC specialist replace drip pan with a new one.
Where to Look – The drip pan is placed just beneath the evaporator coils of your system.
Blocked condensate line
The condensate line, a tiny PVC pipe, sits next to the condenser unit. The condenser unit, a crucial part of your air conditioning system, is located outside your home. Its duty is to discharge the drip pan’s water into your landscape or a storm drain.
Because of its small size, it’s also one of the most common places for mould, mildew, and sludge to grow. This causes blockages in your pipes, as well as musty aromas in your house.
Where to Look – The condensate drain line is a short pipe that travels from the inside of your home to the outside of your air conditioner.
Evaporator coils have been frozen
Your air conditioner takes warm air from inside, cools it, and then circulates it through return vents. This procedure requires unobstructed circulation, therefore air filters must be clean.
As dirt and debris obstruct airflow, water droplets from the humid interior air collect on the evaporator coils. As the refrigerant in the air conditioner unit cools the air, these water drops will freeze. To restore optimal airflow, your HVAC expert will need to let the condenser coil thaw and change the filters.
Where to look – The evaporator coils are positioned inside or near the air handler, which is where your unit’s blower fan is housed.
