How to remove mold in air conditioners

Black mold in air conditioner

Air conditioners provide relief from the summer heat and, more importantly, helps create unfavorable conditions for mold growth within your home. However, the inside of your unit can be a mold breeding ground. If this is the case, spores blow out and spread throughout your home whenever you run it, which causes allergy symptoms in family members and pets. We will reveal some black mold in the air conditioner telltale signs, how to remove it, and what you can do to prevent it.

Topics Covered

  • What are the risks of mold in air conditioners?
  • What are the signs of mold in air conditioners?
  • The best AC cleaning tools
  • How to clean mold from the air conditioner
  • How to clean the AC styrofoam
  • How to prevent mold in the air conditioner

What are the risks of mold in air conditioners?

Mold growth in air conditioners can pose several risks to both your health and the performance of the unit. It’s important to be aware of these risks and take necessary actions to address mold issues promptly. Here are some key points to consider:

Increased allergy symptoms

Mold releases spores into the air, which can be inhaled and cause various health issues, especially for individuals with allergies, asthma, or weakened immune systems. Common symptoms of mold exposure include respiratory problems, coughing, sneezing, itchy eyes, and skin irritation. Also, prolonged exposure to mold can lead to more severe health complications.

Reduced cooling efficiency and performance

Mold growth can interfere with the proper functioning of your air conditioner. The presence of mold on the evaporator coils, vents, or other components can obstruct airflow, reducing the cooling efficiency of the unit. This can result in increased energy consumption, higher utility bills, and an overall decline in the performance of your AC.

Potential system damage

Mold can cause damage to various parts of your air conditioning system. It corrodes metal surfaces, degrades insulation, and clogs drain lines, leading to water leaks and potential water damage. If left untreated, mold growth can contribute to the deterioration of the AC unit, resulting in costly repairs or even the need for a complete replacement.

What are the signs of mold in air conditioners?

Detecting mold growth in your air conditioning system is essential for taking timely action and preventing further contamination. Here are some common signs that indicate the presence of mold in your AC:

Musty or Unpleasant Odors: One of the most noticeable signs of mold in air conditioners is the presence of musty or unpleasant odors when the unit is running. These odors can be strong and distinct, often resembling a damp or earthy smell. If you consistently notice such odors coming from your vents, it’s likely that mold is growing within your AC system.

Visible Mold or Mildew: In extreme cases, you may be able to see visible mold growth on the vents, air registers, or inside the air conditioner unit itself. Mold can appear as dark patches, black or green spots, or fuzzy growth. Check the visible parts of your AC system, such as the filter, coils, and drip pan, for any signs of mold or mildew buildup.

Allergy Symptoms or Respiratory Issues: Mold spores released by the air conditioner can trigger allergic reactions in sensitive individuals. If you or your family members experience frequent allergy symptoms like sneezing, coughing, watery eyes, or worsening asthma symptoms when the AC is running, it could be a clear indication of mold contamination.

Water Leaks or Excess Moisture: Mold thrives in moist environments, so if you notice water leaks, condensation, or excessive moisture around your air conditioner, it increases the likelihood of mold growth. Check for signs of water accumulation, such as wet spots, damp insulation, or water stains near the unit or in the surrounding areas.

The best AC cleaning tools

Here we review a split air-conditioning cleaning waterproof cover bag, a coil cleaning portable pressure washer, and a condenser fin cleaning brush set.

Split air-conditioning cleaning waterproof cover bag

Split Air Conditioning Cleaning Waterproof Cover Bag

The HVAC Yellow Hat split air conditioning cleaning waterproof cover bag is a practical and efficient solution for protecting your walls and surroundings during the process of cleaning wall-mounted air conditioners.

With its waterproof design and convenient features, it aims to provide full protection and ease of use.

Waterproof Design and Durability

The cleaning bag features a waterproof layer made of high-grade jacquard fabric. This not only adds to its practicality but also enhances its visual appeal. The tight stitches and sealing strip ensure durability and high-quality construction, allowing for repeated use without compromising its effectiveness. The solid outlet is perfectly connected with the aqueduct, which provides a secure and firm connection that won’t fall off during use.

Full Protection and Water Management

It also prevents splashing and splattering of dirt and water during the cleaning process. It comes with a large piece of waterproof curtain and three small pieces of waterproof films, effectively shielding your walls and surrounding areas from any potential mess. Additionally, the drain outlet and water pipe allow for easy and efficient water drainage into a bucket, making the cleaning process more convenient.

Size and Compatibility

The cover bag with dimensions of 10.63 x 10.63 x 39.37 inches (270 x 270 x 1000mm). This size is suitable for most split air conditioners commonly found in homes, offices, hotels, shops, and other similar environments. Its versatility ensures that it can be utilized in various settings, providing a reliable solution for cleaning wall-mounted air conditioners.

High-Quality Construction

The construction of this cleaning cover is impressive, with neat and firm stitches that contribute to its overall durability. The use of high-quality Velcro and elastic bands ensures a secure fit and allows for repeated use without fear of damage. This product is designed to withstand regular cleaning sessions, providing a reliable tool to assist you in completing air conditioning cleaning tasks effectively.

HVAC coil cleaning portable pressure washer

HVAC coil cleaning portable pressure washer

The ZPB140 HVAC Coil Cleaning Portable Pressure Washer is a compact and efficient solution for cleaning evaporator and condenser coils, mini-split indoor coils, and outdoor coils.

With its rugged housing, lightweight design, and convenient features, it offers versatility and convenience for both home use and on-the-go mobile cleaning services. In this product review, we’ll explore its key features, benefits, and overall performance.

Rugged Housing and Lightweight Design

This portable pressure washer has a rugged housing that ensures durability and long-lasting performance. Despite its sturdy construction, the unit remains lightweight, allowing for easy portability and maneuverability. Whether you need to clean coils at home or provide mobile cleaning services, this machine is designed to withstand the demands of various environments.

Convenient Onboard Storage Cabinet

The ZPB140 comes with an onboard storage cabinet, providing a secure and organized space for keeping all the necessary accessories. This allows you to have quick and easy access to durable quick-connect hoses, a wand, and a trigger sprayer, ensuring that all components are kept safe and within reach during the cleaning process.

Pressure-Activated Pump and Adjustable Settings

The pressure-activated pump enables the unit to deliver two pressure settings, allowing for versatile indoor and outdoor cleaning. Whether you need to clean stubborn dirt and debris on indoor coils or perform thorough cleaning on outdoor coils, the adjustable pressure settings provide the flexibility to meet your specific cleaning requirements.

Safe and Effective Operation

It is powered by a 120V electric source, ensuring reliable and consistent performance. It is important to note that this pressure washer can only be used with non-acidic coil cleaners. The machine operates at a maximum pressure of 140 PSI and a flow rate of 0.25 gallons per minute (GPM). With a temperature range of 35°F to 120°F (1.66°C to 48.89°C), it offers versatility for cleaning coils in various temperature conditions.


It’s essential to be aware of certain limitations of this portable pressure washer. It cannot be connected to a garden hose and is not battery-powered. Additionally, it is designed to be used with water only and cannot be used to spray air. Understanding these limitations ensures that the machine is used correctly and optimally for air conditioner coil cleaning purposes.

3-piece air conditioner condenser fin cleaning brush

3-piece air conditioner condenser fin cleaning brush

The air conditioner condenser fin cleaning brush set is a practical and efficient tool for cleaning air conditioner condenser fins and coils.

With its combination of a stainless steel air conditioner fin cleaner and two air conditioner condenser fin cleaning brushes, this set provides the necessary tools to effectively remove dirt and debris from your cooling system.

Versatile Cleaning Set

This product includes 1 stainless steel air conditioner fin cleaner and 2 air conditioner condenser fin cleaning brushes. The combination of these brushes allows for efficient and comprehensive cleaning of condenser fins and coils. Whether you need to straighten deformed condenser fins or remove dirt and debris, this versatile cleaning set has you covered.

Sturdy Construction and Design

The air conditioner fin cleaner features a stainless steel handle that provides durability and a comfortable grip during cleaning. The plastic brushes in the set have stiff and smooth bristles that effectively clean the condenser fins and coils without causing damage. The round shape of the brushes allows for easy maneuverability and access to tight spaces, ensuring thorough cleaning.

Effective and Efficient Cleaning

The plastic condenser fin cleaning brushes are specifically designed to clean in-line condensers. By pulling the holder inward and inserting the brush’s curved head inward, you can effectively remove dust and debris or straighten any deformed condenser fins. The stainless steel fin cleaner is suitable for general cleaning purposes, making it a versatile tool for maintaining the efficiency of your air conditioning system.

How to clean mold from the air conditioner

Cleaning your air conditioning unit regularly helps maintain its efficiency and prevents mold growth. Here’s a step-by-step guide to cleaning various components of your AC system:

Turn off the power

Before starting any cleaning or maintenance tasks, ensure the power to the AC unit is turned off. Locate the circuit breaker associated with the unit and switch it off to avoid any electrical accidents.

Clean the vents and registers

Start by removing the vent covers and registers from the walls or ceiling. Use a vacuum cleaner with a brush attachment to remove dust, dirt, and debris from both the covers and the vent openings. If necessary, wash the covers with mild soap and water, and ensure they are completely dry before reinstalling.

Clean the air filters

Locate the air filters in your AC system. Depending on the type, they may be located in the return air grille or inside the air handler unit. Remove the filters and inspect them for dirt and debris. If they are disposable, replace them with new filters. If they are reusable, clean them according to the manufacturer’s instructions using a vacuum or mild soap and water. Ensure the filters are completely dry before reinstalling.

Clear the condensate drain line

Locate the condensate drain line, which is a small PVC pipe usually connected to the indoor air handler unit. Check for any clogs or blockages in the line. You can use a wet/dry vacuum or a pipe cleaner to clear any debris or algae buildup. Alternatively, you can flush the line with a mixture of equal parts water and vinegar to prevent mold growth. Ensure the line is clear and draining properly.

Clean the evaporator coils

The evaporator coils are located inside the air handler unit. Use a soft brush or a fin comb to gently remove any dust, dirt, or debris from the coils. Just be extra careful not to bend or damage the delicate fins. If the coils are heavily soiled, you can use a coil cleaning solution specifically designed for AC units. Follow the instructions on the cleaning solution and rinse the coils thoroughly with water after applying the solution.

Inspect the condenser unit

Head outside to inspect the condenser unit. Clear away any debris, such as leaves, grass, or branches, that may have accumulated around the unit. Ensure that the unit is free from obstructions and has proper airflow. You can use a soft brush or a vacuum cleaner with a brush attachment to clean the exterior fins of the condenser unit.

Check and clean the fan blades

Locate the fan blades inside the condenser unit and inspect them for any dirt, dust, or debris. Use a soft brush or a cloth to gently clean the blades. Be careful and don’t bend or damage the blades while cleaning.

Reassemble and restore power

Once you have completed cleaning the various components of the AC unit, reassemble the vent covers, registers, filters, and condenser unit panels. Double-check that everything is properly secured. Then, turn the power back on by switching on the circuit breaker associated with the AC unit.

How to clean the AC styrofoam

When cleaning an AC unit, it’s important to address the styrofoam insulation that may be present. The styrofoam insulation is typically found around the refrigerant lines and helps prevent condensation and maintain temperature efficiency. Here’s how you can clean the styrofoam insulation:

Inspect the styrofoam insulation

Carefully examine the styrofoam insulation around the refrigerant lines and look for any signs of mold, dirt, or damage. If you notice significant mold growth or damage, it may be necessary to replace the insulation. Consult a professional HVAC technician for guidance on replacement.

Clean the surface

If the styrofoam insulation appears dirty or has light mold growth, you can clean it using a mild detergent and water solution. Mix a small amount of mild detergent with warm water in a bucket. Dampen a soft cloth or sponge in the solution and gently wipe the surface of the styrofoam insulation. Avoid excessive rubbing or applying too much pressure, as it can cause damage.

Rinse and dry

After cleaning, rinse the surface of the styrofoam insulation with clean water to remove any detergent residue. Ensure that you thoroughly rinse the insulation to prevent any residual soap from accumulating. After rinsing, allow it to air dry completely before restoring power to the AC unit.

Inspect for damage

While cleaning, take the opportunity to inspect the styrofoam insulation for any signs of damage, such as cracks, tears, or deterioration. Damaged insulation may compromise its effectiveness and require replacement. If you notice any significant damage, it’s best to consult a professional HVAC technician for proper evaluation and replacement.

It’s also worth noting that styrofoam insulation is delicate, so it’s important to handle it with care during the cleaning process. Avoid using abrasive materials or harsh chemicals that could damage the insulation. If you’re unsure about cleaning or dealing with the styrofoam insulation, it’s always recommended to seek assistance from a qualified HVAC technician who can provide proper guidance and ensure the integrity of your AC unit.

How to prevent mold in the air conditioner

Preventing mold growth in your air conditioning system is key to maintaining a clean and healthy indoor environment. By implementing the following preventive measures, you can reduce the likelihood of mold recurrence in your AC:

1: Proper Ventilation: Ensure proper ventilation in your home, especially in areas where the air conditioner is located. Good airflow helps prevent the accumulation of moisture and minimizes the conditions conducive to mold growth. Keep vents unobstructed and consider using fans or opening windows to promote air circulation.

2: Humidity Control: Maintain optimal humidity levels in your home, particularly during humid seasons or in areas with high humidity. Use dehumidifiers to reduce excess moisture in the air, aiming for humidity levels between 30% and 50%. This will create an inhospitable environment for mold growth.

3: Install UV Lights: UV lights installed in the air conditioning system can help kill mold spores and prevent their growth on surfaces. These lights emit ultraviolet radiation that disrupts the DNA of mold and other microorganisms, which prevents them from reproducing.

4: Promptly Address Water Leaks: Any water leaks or excess moisture around your air conditioner should be addressed immediately. Regularly inspect the system for signs of leaks, such as water stains, wet spots, or condensation. Fix any leaks as soon as possible and ensure proper drainage from the condensate line and drip pan to prevent standing water.

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