10 Most Common Aircon Problems In Older Singapore HDB Flats

Living in an older HDB flat has its charm, mature estates, spacious layouts, and a great location. But when it comes to appliances like your aircon, time isn’t always on your side. Older HDB units often experience more aircon issues due to outdated wiring, worn-out infrastructure, and years of daily use.

Whether you’re a long-time homeowner or just moved into a resale flat, here are the 10 most common aircon problems in older HDB homes—and how to fix them before they escalate.

1. Weak Cooling or No Cold Air

This is one of the most common issues in older flats. Over time, your aircon may struggle to cool the room as efficiently as it used to. Possible causes include dirty filters or condenser coils, low refrigerant gas, poor ventilation or insulation, or a clogged drainage pipe.

You could fix that by cleaning or replacing the air filters. If the issue persists, schedule a chemical wash or check for gas leaks. Consider improving room insulation to reduce heat gain.

2. Aircon Leaking Water

Water dripping from your indoor unit is never a good sign. In older HDB flats, this problem is more frequent due to wear and tear. They can be caused by clogged or damaged drainage pipes, dirty filters leading to coil freezing, or even improper installation.

However, you don’t have to worry that much. All you can do is clear the drainage pipe and clean the filters regularly to maintain optimal performance. For recurring leaks, have a technician inspect the pipes for cracks or alignment issues.

3. Unusual Noises During Operation

If your aircon sounds like it’s hosting a rock concert — buzzing, rattling, or grinding — it’s probably time for a check. So, what’s the cause behind all the noise then? Well, it could be due to loose internal parts (like fan blades), worn-out motors or belts, or debris stuck inside the unit.

What should you do should you hear weird noises then? The wise thing to do is to switch off the aircon and call a professional immediately. Continuing to use a noisy aircon may lead to internal damages which would definitely be costlier to repair.

4. Foul Smell From The Aircon

In older flats where aircons haven’t been maintained regularly, unpleasant smells can spread throughout the room. Root causes for the smell often leads to mould or mildew buildup, clogged drainage or stagnant water, or dead pests inside the unit (yes!).

You may opt for an aircon chemical wash. This deep-cleaning service kills bacteria, removes mould, and freshens the entire unit.

5. Frequent Power Trips When Using the Aircon

Some older HDB flats aren’t designed to support high electrical loads, especially with multiple aircon units running. All you have to do is check for old or faulty circuit breakers, overloaded power circuits, or short circuits within the aircon unit. Then hire a licensed electrician to inspect your electrical panel. Possible recommendations would include rewiring or isolating the aircon circuit to prevent future trips.

6. Remote Control Malfunctions

Sometimes, the issue lies not with the aircon but with the remote. If you’re pressing buttons and getting no response, it’s worth checking. Common issues would include dead batteries or faulty sensors, disconnected signal receivers, or the remote’s incompatibility with older models.

The first thing you should do is replace the batteries. If that doesn’t work, try using a universal aircon remote. Otherwise, get the receiver checked or replaced.

7. Short Cycling (Turns On and Off Repeatedly)

Short cycling causes inefficiency, stress on the compressor, and higher utility bills. Likely reasons could be overheating components, an incorrect thermostat placement, or clogged filters or blocked airflow.

If this happens, immediately schedule your aircon for servicing. Technicians can clean internal components, check the thermostat location, and ensure your unit isn’t overheating.

8. High Electricity Bills

Older aircon models are often less energy-efficient, especially when combined with poor insulation or infrequent servicing. The main energy draining culprits are old compressors or fan motors, lack of maintenance, or running on outdated energy settings.

Consider upgrading to an inverter model with an energy-saving rating. Meanwhile, regular servicing can reduce strain and lower energy use.

9. Mould & Dust Accumulation

In humid climates like Singapore, mould grows fast. In older HDB flats, where ceilings may have minor leaks or hidden dampness, aircons are particularly vulnerable. Signs to look out for are visible black spots on vents, musty smell when switched on, allergy flare-ups or sinus irritations.

Go for a chemical wash every 6–12 months. Additionally, use a dehumidifier if the room tends to retain moisture.

10. Outdoor Unit Malfunctions

In older blocks, the compressor unit is usually mounted on a metal bracket or on the ground, where it’s exposed to heat, rain, and corrosion. Frequent issues include, rust and corrosion, compression overheating, and dirt or debris clogging airflow.

Clean the outdoor unit regularly and ensure it’s placed in a well-ventilated area. If it’s making strange noises or not functioning properly, call a professional for an inspection.

How Often Should You Service Your Aircon in an Old HDB Flat?

For older units, the general recommendation is:

• General servicing: every 3–4 months
• Chemical wash: every 6–12 months
• Overhaul: once every 1–2 years (especially for units over 5 years old)

You can book these services online through platforms like StringsSG, which offer instant quotes, trusted reviews, and same-day support.

Final Thoughts

An aircon is a staple in every Singapore home. However, in older HDB flats, aircon problems tend to appear more frequently due to years of use and outdated systems. Don’t wait until it breaks down completely—regular servicing and prompt action can save you money and headaches in the long run.

By identifying these 10 common issues early, you’ll ensure a cool, clean, and comfortable home throughout the year.