Why is my new aircon not cooling well?
A new aircon that cools poorly rarely has a fault in the unit or its R32 gas. The usual causes are an outdoor unit that cannot get fresh air, a dirty condenser, or a refrigerant charge not set back correctly after a leak repair. A technician can confirm which by checking the outdoor unit and the gas charge.
Key takeaways
- R32 is not the excuse: a correctly installed and charged R32 system should cool a room as well as an older one.
- The outdoor unit needs air on all sides: boxed-in units run too hot and cool less.
- Leak repairs are a common trigger: systems that are not re-evacuated and recharged properly afterwards never cool as they should.
- Ledges get dirty fast: bird droppings and nesting can clog a brand new condenser coil.
In the video above, Uncle Eric shows a first servicing visit on a brand new R32 aircon. The outdoor unit was running too hot, its ledge was covered in bird droppings, and the unit had been installed in a position that blocked its fresh air intake.
Is it true that R32 aircons are less cold?
No. Some vendors tell customers that new R32 systems are simply not as cold as older ones, and some owners hear the same from the manufacturer's engineer after a check finds "nothing wrong". Yet many of those owners notice a big difference compared with the aircon they had before. When a new system underperforms, the unit itself is often fine. The problem sits around it: where the outdoor unit is, how clean it is, and how the refrigerant circuit was set up.
How can I tell what is causing it?
Work through these checks in order:
- Check the remote. Set cool mode at 24°C to 25°C with the fan on high, not auto. If it was on dry or fan mode and now cools well, the system is fine.
- Clean the indoor air filters. If cooling recovers, the filters were the problem.
- Compare the rooms. On a System 2, 3 or 4, if only one room is weak, the cause is likely in that indoor unit. If every room is weak, look at the outdoor unit and the gas charge.
- Look at the outdoor unit from a safe position. If it is boxed in, pushed tight against a wall or its fins are coated in droppings, airflow is the likely cause.
- Check the outdoor fan. If it is not spinning while the aircon is cooling, the fan motor or its control has a fault.
If step 4 or 5 points to the outdoor unit, or the gas was repaired recently, book a cooling check. Never climb onto a ledge or open the outdoor unit yourself; working at height is a job for a technician with safety equipment.
What does a technician check?
Finding | Likely cause | Fix |
|---|---|---|
Outdoor unit running very hot | Outdoor unit starved of fresh air, or a dirty condenser coil | Clean the condenser, clear or reposition the unit |
Weak cooling that started after a leak repair | Refrigerant charge not reinstated correctly | Find and fix any remaining leak at the pipe joints or valves, evacuate, recharge to the maker's specification |
Ice on pipes or the indoor coil | Low charge or very poor airflow over the evaporator | Leak check, clean the coil and blower fan, recharge |
One room weak on a multi-split | Indoor unit or its expansion valve (EEV) | Clean or repair that indoor unit |
We measure the gas charge with proper tools, so it is set to the manufacturer's specification rather than guessed.
Why does the outdoor unit matter so much?
The outdoor unit (condensing unit) pushes heat out of your home, and it needs fresh air on all sides to do it. If its hot exhaust is drawn straight back in, the system runs hotter and cooling drops. As Uncle Eric says in the video, always position the unit so fresh air can enter from all sides.
Singapore ledges add another problem. On the job in the video, the first step was cleaning the heat exchanger. We found a baby bird and an unhatched egg and worked carefully around them. Bird spikes had not kept the birds away; in our experience they rarely do. For more, read our post on outdoor unit problems in Singapore homes.
Why do leak repairs leave new systems weak?
From 2023 to 2025 we have seen a pattern: a new system develops a gas leak soon after installation, the installer comes back to fix it, and the system is not reinstated to the condition it should be in. After any repair that opens the circuit, the pipes should be tested for leaks, evacuated to pump out the air and moisture, and recharged with the correct amount of refrigerant. Skip a step and the aircon runs, but never cools as it should. Our post on why evacuation matters explains why the vacuum stage is so important.
If your aircon was fine at first and only became weak after a servicing, see serviced but still not cold. For older systems, start with the most common reasons an aircon is not cold. Uncle Eric follows up on this job in watch: Part Two, new aircon with poor cooling.
When to call a technician
Call a technician if your new aircon:
- never reaches the set temperature, even with clean filters and correct settings
- feels much weaker than the old system it replaced
- had a gas leak repaired and has not cooled properly since
- has an outdoor unit that is boxed in, very dirty or running unusually hot
- shows ice on the pipes or a blinking error light
We check outdoor unit placement, clean the condenser, check and correct the gas charge as part of our aircon repair and troubleshooting. Book online in under a minute, or chat with Luna on WhatsApp any time.
Frequently asked questions
Is my new aircon still under warranty if it is not cooling well?
Most new systems come with a manufacturer warranty on parts and an installer warranty on workmanship, so contact your installer first. If the brand's engineer finds nothing wrong with the unit itself, ask for the installation to be checked: outdoor unit placement, gas charge and pipework.
Will installing bird spikes on my aircon ledge help?
In our experience, bird spikes on aircon ledges rarely solve the problem. Birds still nest around the outdoor unit and the droppings clog the condenser coil. Proper bird control and regular cleaning of the outdoor unit work better.
How soon after installation should a new aircon be serviced?
Follow your warranty terms, but do not wait for a problem. The first servicing visit is a good chance to check the outdoor unit, the drain and the cooling performance while the system is still new, which is when installation faults are easiest to raise with the installer.
Is it safe to keep running a new aircon that cools poorly?
For a short time, yes, but it is not good for the system. An outdoor unit that runs too hot, or a system with the wrong gas charge, puts extra strain on the compressor, which is the most expensive part to replace.
Can moving the outdoor unit fix poor cooling?
Sometimes. If the unit is boxed in or blowing its hot air straight back into its own intake, repositioning it so fresh air reaches all sides can bring its cooling back to normal. Moving an outdoor unit means handling the gas and evacuating the pipes again, so it is a job for a technician.
Eric Lim, aka Uncle EricFounder of iAircon.Repair, now in its 10th year servicing aircons in Singapore. Every job is filmed, so you can watch the work on YouTube.
