What Is Aircon Jelly and Why Is It Clogging Your Unit?

Key Takeaways

• Aircon jelly, also known as bio-slime, is a sticky residue that forms when moisture, dust, and bacteria accumulate inside the drainage system.
• This buildup can block water flow, cause unpleasant odours, and lead to leaks from the indoor unit.
• To keep your system in good condition, regular servicing, good ventilation, and periodic deep cleaning by professionals are essential.

Spotting the Signs of Slime Build-up in Your Aircon

If your air conditioner is leaking water or you’ve noticed strange slime coming from the drainage pipe, you might be dealing with a case of aircon jelly. This gooey substance is one of the most common causes of water leaks and odours in air conditioning systems, particularly in Singapore’s humid environment.

While it may seem harmless at first, ignoring this problem can lead to expensive repairs and unhealthy indoor air. Let’s explore what the jelly is, why it forms, and how to prevent it from taking over your cooling system.

What Is Aircon Jelly?

Aircon jelly, also known as bio-slime, is a thick, slimy buildup that forms inside your air conditioning unit’s drainage system. It’s made up of dust, moisture, bacteria, and organic debris that accumulate over time.

In Singapore’s humid climate, the combination of condensation from cooling coils and trapped dirt creates the perfect environment for microbial growth. This is why even well-maintained systems can eventually develop jelly if they go too long without deep cleaning.

Over time, this sticky residue clings to the inner walls of drainpipes and pans, reducing water flow and allowing more bacteria to thrive.

Why Is It a Problem?

While the jelly might look like harmless sludge, it can cause several serious issues if left untreated:

1. Clogged Drainage

One of the first signs of a drain clog is water pooling or dripping from the indoor aircon unit. When jelly blocks the drainpipe, condensation water cannot escape properly, leading to leaks and potential water damage.

2. Foul Odours

A strong musty or sour smell coming from your unit is another warning sign of slime buildup. Bacteria and mould inside the system produce unpleasant odours that circulate throughout your home when the aircon is switched on.

3. Mould and Allergens

The jelly provides a breeding ground for mould spores and allergens, which can affect indoor air quality and trigger respiratory discomfort in sensitive individuals.

4. Reduced Performance

When drainage and airflow are restricted, your air conditioning system has to work harder to maintain cooling efficiency. Over time, this added strain increases energy consumption and can shorten the lifespan of your components.

How to Prevent and Remove Aircon Jelly

Once the jelly takes hold, a quick wipe or drain tablet won’t be enough to eliminate it. Here’s how professionals typically deal with the issue and how you can prevent it in the future:

1. Schedule a Professional Chemical Wash or Overhaul

A professional aircon chemical wash is the most effective way to get rid of aircon jelly. During this process, technicians dismantle key components such as the evaporator coil, fan blower, and drainpipe, then flush them with a specialised chemical solution that dissolves hardened bio-slime and kills bacteria. For severe or recurring cases, a full chemical overhaul may be required. This deep-cleaning procedure restores the system to near-original condition, ensuring smooth water flow and preventing future blockages.

2. Use Antibacterial Drain Tablets Between Servicing

While a chemical wash is the only way to completely remove the jelly, antibacterial drain tablets can help slow its return. When placed in the drain pan, these tablets release cleaning agents that control bacterial and algae growth, keeping the drainage line clearer for longer. They are best used as preventive maintenance between professional servicing sessions.

3. Maintain Good Ventilation

Humidity is one of the main factors that encourages jelly formation. To reduce moisture buildup, keep rooms well-ventilated and avoid setting your air conditioner to extremely low temperatures for long periods. Ensuring steady airflow and proper insulation also helps minimise excess condensation within the unit, making it harder for bio-slime to form.

A Clean Aircon Is a Healthy Home

In Singapore’s tropical climate, the formation of aircon jelly is a sign that your air conditioning system needs attention. Left untreated, it can lead to issues like aircon leaks, foul odours, and poor air quality. Regular aircon servicing, including periodic chemical washes or aircon overhauls, can help your system remain free from build-up and performance problems all year round. 

At Cool Channels Engineering, we help homeowners and businesses resolve air conditioning issues with professional cleaning and maintenance services. With over 15 years of industry experience, our team ensures your system remains clean, efficient, and reliable—so you can enjoy lasting comfort without disruptions.

Book a consultation with us today.