What does an air conditioner fan wheel do?

Air conditioners work by using refrigerant as a heat exchange medium.

The heat is exchanged by passing air over an evaporator coil through which cooled refrigerant is flowing, the air is cooled as it passes over the coil and is then blown into the room \ space being air conditioned.

It is the air conditioner fan wheel (ac blower fan) which is responsible for moving the air on the indoor unit of an air conditioner.

How does an an air conditioner fan wheel get dirty?

In a high wall split system (the one where the indoor unit is mounted on the face of a wall) the fan wheel (blower wheel) gets dirty through the following process:

  1. when the air conditioner is in operation the fan wheel gets moist
  2. when the air conditioner stops any dirt in the air settles on the moist fan wheel and sticks to it
  3. as the dirt builds on the fan wheel, this creates an environment that is conducive to the growth of mould
  4. once the mould starts growing you need a full clean to get rid of it

This is most often seen in a high wall split systems. It is not as common in ducted air conditioners as the filtration on a ducted system prevents most of the dirt from reaching the fan wheel.

What is the impact of a dirty air conditioner fan wheel?

  • Reduced air flow. The most immediate impact of a dirty fan wheel (dirty blower wheel) is a reduced volume of air being moved by the fan wheel. The effectiveness of the fan wheel is highly dependent on the profile on the leading edge of the fan – which if it is covered in dirt and mould – will be compromised.
  • Increased power consumption. As the fan is not as effective, impairing air flow, the air conditioning system has to work harder to achieve the same outcome. It is like driving you car around with the hand break on.
  • Water leaks. If the air conditioner fan wheel (ac blower) is dirty, heat transfer in the ac unit is reduced. If the air flow is very low, it can cause the air conditioner coil to ice up. When that ice melts it can offer cause water leaks that run down your wall.
  • Increased wear and tear on fan wheel motor. As the fan is moving less air, and the fan wheel weighs more (due to the dirt and mould), the fan motor is working harder and will wear out faster.
  • Air con will go into fault. If the heat exchange is sufficiently reduced the air conditioner can go into fault due it sensing a pressure issue.

You should also read: You Could Be Suffering From a Refrigerant Leak

When do you need to clean an air conditioner fan wheel?

You can normally see when a fan wheel needs cleaning. The easiest way to do this is as follows:

  • Gently open front louvres on air conditioner – you should not need to use any force to do this.
  • Shine a torch into the space behind the louvres and you will see the fan wheel
  • If there is any dirt \ mould on the fan wheel it should be cleaned. Once the deposited matter starts, it usually builds quickly.

How do you clean a dirty air conditioner fan wheel?

There are two ways to effectively clean a dirty air conditioner fan wheel:

  1. Strip Clean: This involves removing the fan wheel from the indoor unit and cleaning it outside the system. This is not our preferred method of cleaning as repeated removal of the fan wheel increases the risk of breaking components of the air conditioner. These components are normally plastic – and become increasingly brittle with age.
  2. Hydro Clean: This involves partially disassembling the indoor unit. Once this is done a catch bag is placed under the indoor unit. The indoor coil and fan wheel are then sprayed with a cleaning agent. The cleaning agent (and the dirt and mould) are then removed with a low pressure water washer. Whilst there is still some risk of breaking plastic parts of the ac unit, the risk is reduced as we remove less parts.

How often should you need to clean an air conditioner fan wheel?

There are two main determining factors when it comes to the frequency you need to have your air conditioner fan wheel (ac blower wheel) cleaned:

  1. How frequently do you use your air conditioner: the more you use it the more often it will need to be cleaned.
  2. How much dirt is there in the air: the more air borne dirt there is the more frequently it will need to be cleaned. For example if you live beside a busy road there will be more air borne dirt. Whereas if you live on the 20th level of an apartment block there will be hardly any air borne dirt.


If your conditioner fan wheel (blower wheel) is dirty it should be cleaned to improve the hygiene and efficiency of your air conditioner.

As part of a standard service of your air conditioner the technician can tell you whether you need your fan wheel cleaned or not.

At AbelAir Services we carry out over 2,500 jobs per year. Our combined experience, together with our trained and knowledgeable tradesmen mean we are perfectly placed to diagnose and repair your air conditioner in Maryland.