When Does an Aircon Need a Gas Top-Up?
Is your bedroom unit blowing lukewarm air, even though the remote says 24°C? That’s usually when people start searching for an aircon gas top-up.
A sealed aircon system shouldn’t lose refrigerant. Gas isn’t used up like fuel, so if the level has dropped, it has gone somewhere. Most often, that means a small leak.
Here’s what low gas usually looks like in a Singapore flat:
- Cooling fades slowly over weeks or months, not overnight.
- Ice forms on the copper pipe. Helpling’s aircon pipe guide lists this as a classic sign of low refrigerant, along with hissing sounds.
- The compressor runs non-stop, but the room never really cools.
- The unit trips off on its own. Coogle notes that many modern units have pressure sensors that shut the system down when refrigerant pressure falls too low.
If you have 2 to 4 wall-mounted units, compare them. When one struggles and the others cool fine, the fault is usually local to that unit. We start with its joints and pipes.
What the technician checks
The technician follows the same order on every visit:
- Read the pressure with manifold gauges on the outdoor unit.
- Look for leaks at the joints and along the pipes.
- Confirm the correct refrigerant (R22, R410A or R32) from the unit’s nameplate.
- Top up the correct refrigerant.
A top-up without a leak check often fails again, so we treat the leak check as part of every job. Otherwise you pay for gas that slowly escapes.
Why the refrigerant type matters
Each refrigerant behaves differently, and the label on your outdoor unit decides which one goes in.
| Refrigerant | Usually found in | Good to know |
|---|---|---|
| R22 | Older units | FixMove’s 2026 price guide notes that supply is tightening, so suitability must be confirmed first. |
| R410A | Many units from the 2010s | It’s a blend, so a heavily depleted system may need a full re-gas instead of a simple top-up. |
| R32 | Newer inverter systems | It must never be mixed with R410A. |
Gas top-up starts from S$80, with a fixed quote before work and a 90-day workmanship warranty. You’ll know the price before we touch a gauge.
If your unit is simply not cold, we’ll check whether low gas or another fault is the cause. Send us a photo of the outdoor unit’s nameplate and tell us what your aircon is doing. We’ll tell you straight whether it needs gas or something else.
