If your aircon used to cool well and is now struggling, low refrigerant is one of the most common culprits — but it’s often misdiagnosed as a cleaning issue or ignored until the unit stops cooling almost entirely. This guide covers how to recognise the signs, why refrigerant levels drop in the first place, and why “just topping it up” repeatedly isn’t always the right fix.
What Refrigerant Actually Does
Refrigerant (commonly referred to as “gas”) is the substance that absorbs heat from indoor air and releases it outside, allowing your aircon to cool the room. Unlike fuel, refrigerant isn’t consumed during normal operation — a correctly sealed system should maintain its refrigerant level indefinitely. If your levels are dropping, something is causing it to leak out, which is an important distinction from a simple “top-up when low” situation.
Signs Your Aircon Is Low on Refrigerant
1. Weak Cooling Despite Normal Airflow
If air is still blowing from the vents but it’s not particularly cold, this is one of the clearest signs of low refrigerant. Unlike a dirty filter (which restricts airflow), low refrigerant usually still allows normal airflow — it’s just not cold.
2. Ice Forming on the Indoor Unit or Refrigerant Lines
Low refrigerant pressure can cause the evaporator coil to get too cold, leading to ice formation. This ice further restricts airflow, making cooling performance worse and creating a cycle that won’t resolve itself without a technician addressing the refrigerant level.
3. Hissing or Bubbling Sounds
A hissing sound near the indoor or outdoor unit can indicate refrigerant escaping through a leak point. This is different from normal operational sounds and is worth having checked promptly.
4. Longer Cooling Times
If your aircon now takes noticeably longer to bring a room to temperature than it used to, reduced refrigerant is a common (though not the only) cause.
5. Higher Electricity Bills for the Same Usage
A system low on refrigerant has to run longer to achieve the same cooling result, which shows up as increased energy consumption even if your usage habits haven’t changed.
Why Does Refrigerant Level Keep Dropping?
This is the part that often gets missed: if your aircon needs frequent gas refills, there’s almost always a leak somewhere in the system. Common leak points include:
- Corroded or damaged refrigerant lines, particularly in older units or coastal areas with salt-air exposure
- Loose or worn flare connections at the joints
- Physical damage to the outdoor unit’s coil
- Manufacturing defects in rare cases with newer units
Simply refilling the gas without finding and sealing the leak means you’ll be back to the same problem within months — and each refill costs money that a proper leak repair would have saved in the long run.
Refill vs Leak Repair: What You Actually Need
- A one-time top-up may be reasonable if the system was recently installed or serviced and lost a small amount during that process
- A leak detection and repair is needed if this is a recurring issue — our technicians use proper leak detection methods to locate the source before refilling, rather than guessing
See our gas refill service for more on how we handle this — leak checks are included as standard practice rather than an optional extra.
Is Low Refrigerant Dangerous to Ignore?
Running a system on low refrigerant for an extended period can cause the compressor — the most expensive component in the unit — to work harder than it’s designed to, potentially shortening its lifespan or causing it to fail entirely. What starts as a relatively inexpensive gas top-up and leak repair can turn into a costly compressor replacement if left unaddressed.
Frequently Asked Questions
How often should an aircon need a gas refill? In a properly sealed system with no leaks, it shouldn’t need refilling at all under normal operation. If you’re refilling every few months to a year, there’s very likely an underlying leak that needs to be found and repaired.
Can I check refrigerant levels myself? Checking refrigerant pressure requires specialised gauges and knowledge of the specific refrigerant type your system uses. This isn’t a DIY task — attempting it without proper training and equipment can be unsafe and may damage the system further.
Is it more expensive to fix a leak than to just keep refilling gas? In the short term, a top-up is cheaper than a full leak repair. Over time, however, repeated refills usually cost more than fixing the leak once, on top of the added strain on your compressor from running low on refrigerant repeatedly.
Does every AC brand use the same type of refrigerant? No — refrigerant type (such as R22, R32, or R410A) depends on the unit’s design and age. Using the wrong type or mixing refrigerants can damage the system, which is why this should always be handled by a technician familiar with your specific unit.
My aircon is cooling fine — do I need a gas check anyway? Not necessarily. If cooling performance is normal and there are no signs listed above, there’s no need to check refrigerant levels as part of routine maintenance unless the unit’s history suggests a past leak.
Get Your Refrigerant Levels Checked Properly
If your aircon is cooling weakly or you’ve noticed ice forming, don’t just keep topping up the gas — let us find and fix the actual cause. Message us on WhatsApp for a diagnosis, call +60 10-593 0730, or check our price list for gas refill and leak repair rates.