Why Your Aircon Has Condensation & How to Stop It

We see water dripping from cooling units almost daily in our line of work. Our team of 26 technicians at Billy Aircon has been providing aircon servicing in Singapore since 2003, and we know that the local average relative humidity of nearly 84% forces your system to constantly pull buckets of moisture out of the air.

Most people panic when they see water on their walls.

A little internal moisture actually shows the system is working properly. Let us explore the main reasons why your aircon has condensation and exactly how to stop it from ruining your paintwork.

Why Condensation Happens

Our technicians often explain this process using a cold glass of water. A cold drink taken outside on a hot Singapore afternoon will instantly form water droplets on the outside of the glass.

Your air conditioning system does the exact same thing.

The indoor unit pulls warm room air over a cold evaporator coil. This internal metal coil typically runs at a chilly 4 to 7 degrees Celsius, and moisture from your room rapidly condenses on this cold surface.

Under normal conditions, these water droplets fall safely into a drainage tray. The water then flows right out of your property through a dedicated PVC drain pipe. Issues only appear when a part of this delicate drainage ecosystem fails.

1. Clogged Drain Pipe

We find that blockages cause nearly 80% of the leaking issues we fix across residential properties. Singapore’s tropical climate creates the perfect breeding ground for biological slime.

Technicians commonly call this thick buildup “aircon jelly,” and it forms rapidly inside the standard 16mm PVC drain pipes used in most local installations.

The condensation water suddenly has nowhere to go once this sludge blocks the exit, so it simply fills up the drainage tray and spills over onto your floor. Booking regular servicing allows technicians to flush out this jelly using high-pressure vacuums before it causes an overflow.

2. Dirty Evaporator Coil

Our maintenance teams frequently encounter coils completely choked with pet hair and household dust. A thick layer of dirt acts like a suffocating blanket on your system.

It restricts vital airflow across the metal fins by up to 30%.

This lack of warm air moving across the surface causes the coil to become exceptionally cold, and the condensation literally freezes into sheets of solid ice right inside your indoor unit. A massive puddle forms quickly when the compressor turns off and that ice rapidly melts into the tray.

3. Low Refrigerant Gas

We always check pressure readings because low refrigerant creates a freezing effect similar to a dirty coil. Most modern residential units in Singapore use R32 refrigerant gas.

Pro Tip: An aircon running with optimal R32 gas levels will display a suction pressure between 110 and 130 PSI on a standard gauge.

The temperature of the evaporator coil drops well below freezing if a tiny leak causes that pressure to fall below 70 PSI. Ice inevitably builds up while the motor runs, and the drainage system gets completely overwhelmed once the room reaches the target temperature and that accumulated ice thaws.

Arranging a proper gas top-up will restore the correct pressure and resolve this freezing cycle entirely.

4. Damaged Pipe Insulation

Our installers wrap the copper pipes connecting your indoor and outdoor units in thick foam to keep the cold in. This material degrades over time due to heat and natural wear within your HDB or condo trunking.

Exposed, freezing copper pipes instantly react with the warm, humid air trapped in your ceiling or walls.

This reaction causes heavy condensation directly on the outside of the pipes, which you will usually spot as mysterious damp patches appearing along your plasterboard. Upgrading to a thicker 1/2-inch Class 1 Armaflex material offers much better protection than the standard 3/8-inch foam builders often use.

You can read more about selecting the right materials in our complete aircon insulation overview.

How to Stop Condensation

We highly recommend taking a proactive approach to system maintenance. The Housing and Development Board takes dripping water very seriously.

Neighbours can report your unit, and repeat offenders face fines of up to $1,000 under the Environmental Public Health Act. You must address pooling water immediately to protect your property and avoid neighbourly disputes.

Condensation Issue	Immediate Action Required	Professional Solution
Water dripping from indoor unit	Turn off the system to prevent electrical damage.	High-pressure vacuum flush of the drain pipe.
Ice forming under filters	Switch to fan mode only to melt the ice safely.	Chemical wash or refrigerant pressure test.
Damp patches on ceiling	Place a bucket underneath and call a technician.	Replace degraded copper pipe insulation.

Following a structured maintenance checklist is the easiest way to keep your walls perfectly dry:

1. Schedule regular servicing: Book a standard clean every 3 to 4 months to stop jelly formation before it blocks the exit.
2. Get a chemical wash: Choose a deep chemical wash if your coils look heavily soiled or if the standard wash no longer improves airflow.
3. Check gas levels: Request a pressure check immediately if you notice cold spots or ice forming along the copper connections.
4. Replace damaged insulation: Ask your technician to inspect the foam wrapping inside your trunking during their annual visit.
5. Ensure proper drain slope: Verify that your drainage pipes angle slightly downward so gravity can effectively pull the water outside.

We urge you to act fast if you notice your system leaking water onto your floors. Delays often turn a minor drainage clog into expensive water damage repairs for your custom carpentry and flooring. WhatsApp us today to arrange a same-day inspection and keep your home cool and dry.