How to Clean Ducted Air Con Filter: A Quick 5-Step Guide

Here is an imaginary scenario. You switch on the AC on a summer day, but even after a few minutes, it doesn’t feel cold enough. 

Sounds familiar? That can make you wonder – what’s wrong with my aircon?

In theory, there can be several reasons for this, and one of the more common is the aircon filter being dirty. Besides reducing cooling efficiency, a dirty system can harm indoor air quality too.

Thankfully, cleaning ducted air conditioner filters is a DIY task and can be done safely. Here, we will discuss how to clean a filter on a ducted air con in a few simple steps.

How to Clean a Ducted Air Conditioner Filter In 5 Steps

In most ducted air conditioning systems, you will find a duct outlet on the ceiling, covered with a metal box and a return air grille. The mesh-type filter is located inside the frame of the grille.

Firstly, check the user’s manual to note if there are any specific filter cleaning instructions. Not to forget that not all filters are designed to be cleaned. Some air conditioners use a filter pack made from more rigid cardboard material. These filters cannot be cleaned like the more common mesh-type filters. They need to be replaced after fixed intervals. Checking the manual will give you a clear idea about the type of filter in the aircon unit.

If there are no specific cleaning instructions, you can use a vacuum cleaner. Otherwise, here are a few things that you will need.

• Warn water,
• A soft bristles brush,
• Mild soap or detergent (you can use a solution of vinegar, and baking soda in water as a substitute).

Note that some manufacturers may advise against using any chemicals on the filter. However, in most cases, they’ll even recommend a mild detergent for cleaning air conditioner components.

Step 1

Needless to say, you need to switch off any electrical appliance before working on it to ensure safety. So, turn the aircon off before rolling up your sleeves.

Step 2

Place a step ladder beneath the return air grille to reach it safely. Some ACs may have multiple filters. So make sure that you take out all of them. It is best not to be too aggressive to remove the filters. Most return air grilles are fixed to the ceiling with thumbscrews below the air duct outlet. 

You may have to remove the grille completely or let it swing down and dangle if it has a hinged connection. Then you can remove the filter media from the frame connected to the grille. Make sure to remember the correct orientation of the filter so that you can place it back properly. Incorrect orientation will reduce the filter performance.

Step 3

To start with, you can use a vacuum or a brush to remove the top layer of dust from the frame. Alternatively, a microfibre cloth or a feather duster can also be used. Take the filter outside and brush it to remove the accumulated dust as much as possible. Or else, you can use a garden hose to hose it down with clean water. Make sure to use gentle water pressure. Filters are too delicate to withstand high water pressure.

To remove the stubborn grime, soak the filters in the soap solution for 15-20 minutes. This will help in removing the stubborn debris sticking to the surface. If the filter is too large for soaking, use the brush to spread the cleaning solution all over the surface. Brush gently to prevent any damage to the filter mesh.

Step 4

Once cleaned, rinse the filters in clean water to remove any residue. Remove the excess water and place it on a clean surface for drying. Note that if the filter has a plastic frame, it’s best not to leave it under the sun. Place it in a warm shaded area for drying. 

While the filter is drying out, you can use the vacuum cleaner to clean the inner surface of the return air grille and the lower end of the duct outlet box. Check for any signs of damage to the box and the duct. In case you detect any damaged surfaces or rips, call the installer for support.

Step 5

Once the filter is clean and dry, it’s time to place it back and fix the grille with the thumbscrews. The aircon filter cleaning is complete. Repeat the process with all the return air grilles in your home. Since ducted air conditioning is an integrated system, any dirt left will quickly whoosh through the entire house. In other words, not cleaning all the grilles more or less amounts to not cleaning any.

How to Know That Your Ducted Aircon Filter Needs Cleaning

The best way to tell whether your aircon filters are ripe for cleaning is to check for dust or grime buildup around the grille. Other signs include strange odours in the house and worsening allergy symptoms. You may also notice an increase in the cooling or heating time and a spike in your energy bills.

In general, the filters should be cleaned before the start of the cooling or heating season. If the AC unit has been lying unused for a few months, clean the filter before use.

Why You Should Not Keep the Aircon Filter Dirty

The fact is, keeping the aircon filter clean is not a choice but a necessity. Take a look at the main reasons for that.

• A blocked filter will obstruct the airflow, forcing the air to seek a different route. This will reduce overall efficiency and cooling effect.
• Dust accumulation on the filters can increase the growth of mould and mildew. The incoming air will carry these contaminants and microorganisms into the room which can result in health risks. The effect can be severe for individuals with respiratory infections or conditions like asthma. In addition, this can also result in the room air smelling musty.
• Keeping the filters clean will reduce the wear and tear of the system. This will help in keeping down the operational, as well as the maintenance costs.

Frequently Asked Questions

What happens if the AC filter is not cleaned?

An unclean filter in a ducted AC will result in poor airflow. Cleaning is necessary to ensure a fresh and clean airflow and keep the system working at the highest efficiency.

How to clean Daikin ducted air con filter?

To clean a Daikin ducted air con filter, check for any specific manufacturer’s instructions in the manual. (Here’s a list of many of their manuals available for download.) If there are no specifications, you can follow the steps we have mentioned for cleaning. The same goes for any other brand!

How long can I use AC without a filter?

Ideally, you should not use an AC without a filter at all. While the unit will run without a filter, there will be a significant drop in the indoor air quality. Plus, the unfiltered dust can damage the mechanical components like the motor and compressor.