Weak airflow and noise issues in window units, and cleaning

One of the most frustrating moments in the hot summer is opening a window-type AC and finding that the unit is making a loud rumbling noise, but the cool air coming out is weak.

Many owners’ first reaction is to suspect insufficient refrigerant or an ageing unit, and even consider replacing it with a new one immediately.

In fact, these three common symptoms—weak airflow, poor cooling and loud noise—are often related to heavy dust buildup inside the unit. A thorough deep clean can often improve the AC's performance.

1. Dust blockage causes a sharp drop in airflow

An AC unit works by drawing in warm indoor air, cooling it through the chilled evaporator fins, and then blowing it back out.

After an AC has been used for some time, the dust filter and the internal heat-dissipation fins can become clogged with thick dust and lint. It is like wearing

Like running with a mask on, air cannot pass through smoothly, causing both intake and output to drop significantly.

Cleaning the filter alone only solves surface issues. Dirt lodged deep between the aluminium fins must be removed to restore strong airflow circulation.

II. Heat exchanger failure causes temperature control malfunction

Many people find that although the air conditioner is running, it never feels cold enough, or the compressor keeps running continuously without lowering the room temperature. This is because dust and dirt on the evaporator surface form an insulating layer, blocking heat exchange between the air conditioner and the air.

If lint is trapped inside the unit and cannot be released, it will not only stop the room temperature from dropping, but also cause icing and dripping inside the unit. Cleaning can remove this insulating layer of dirt, allowing the aluminium fins to contact air again and restore precise temperature control performance.

3. Unbalanced fan is the main cause of noise

Vibration and noise during operation in a window unit often come from the internal cross-flow fan, commonly called a squirrel-cage fan. This cylindrical fan blade easily collects dust and mould. When dust is unevenly distributed, the fan becomes unbalanced while rotating, causing strong vibration and noise similar to a washing machine spinning.

Dust buildup on the fan may affect operation, but abnormal noise may also involve mounting, blades or other parts. First confirm the source of the noise and the condition of the parts. Do not describe cleaning as the fastest or guaranteed solution for all noise problems, and residents should not reach in to handle the fan themselves.

Why is professional help needed?

Deep cleaning a window-type air conditioner involves complex dismantling and reassembly work.

A professional AC cleaning team uses specialised high-pressure cleaning guns that produce a powerful water jet, directly breaking up and washing away stubborn mould hidden deep in the aluminium fins and fan blades. This effect cannot be achieved with a household spray can.

Professional technicians are strictly trained and know how to properly wrap the circuit boards and capacitors inside the unit to prevent moisture from getting in and causing short circuits or burnouts. For window units installed in hazardous locations or with exceptionally heavy weight, the professional team has the capability and safety equipment for working at height, ensuring the cleaning process will not soil your home or cause falling-object accidents, so owners can regain a quiet, cool space safely and worry-free.

When a window unit shows signs of abnormal operation, it is recommended to check whether cleaning is needed. Regular deep cleaning can solve weak airflow and noise caused by dust buildup, help reduce extra load on components, and maintain everyday operating performance.