Ranked by indoor noise
The quietest split systems sold in Australia.
Noise is the specification people regret ignoring. A unit that is 6 dB louder than another sounds roughly twice as loud to the ear, and in a bedroom that is the difference between background hum and the thing that wakes you at 3 am. Every model below publishes a declared indoor sound level on the government register.
Quick answer
On the Australian Government's GEMS register, the lowest declared indoor sound level among wall-mounted single-phase reverse-cycle models is 47 dB, held by the Mitsubishi Heavy Industries SRK20ZTA-WF (registration AAC10044), a 2 kW unit. Sound figures are published for 363 of the models on the register. Bear in mind that the quietest unit overall is only useful if it comes in the capacity your room needs — the quietest model in each size class is listed further down.
The ranking
Top 15 across every capacity.
Drawn from all 380 registered models, capped at three per brand so one manufacturer's range cannot fill the table. Efficiency generally falls as capacity rises, so a list ranked across all sizes leans towards smaller units — which is exactly why the per-size table below it is the one to buy from.
| Model | Cooling | Heating | Indoor noise | AEER | ACOP | Stars | Registration |
|---|---|---|---|---|---|---|---|
| Mitsubishi Heavy IndustriesSRK20ZTA-WF+2 variants | 2 kW | 2.7 kW | 47 dB | 4.69 | 5.03 | 5 / 4 | AAC10044 |
| TCLTPH11IT | 2.64 kW | 4.05 kW | 47.19 dB | 4.34 | 4.06 | 5.5 / 2.5 | AAC7692 |
| TecoTWS-TSO26H3DVJT | 2.64 kW | 4.05 kW | 47.19 dB | 4.34 | 4.06 | 5.5 / 2.5 | AAC7258 |
| TecoTWS-TSO26HVEIT | 2.64 kW | 4.05 kW | 47.19 dB | 4.34 | 4.06 | 5.5 / 2.5 | AAC6384 |
| TCLIH+5 variants | 2.8 kW | 2.65 kW | 47.7 dB | 5.11 | 5.54 | 5 / 3.5 | AAC8485 |
| TCLVAIH+3 variants | 2.8 kW | 2.65 kW | 47.73 dB | 5.11 | 5.54 | 5 / 3.5 | AAC8101 |
| TecoTWS-TSO35H3DVJT | 3.5 kW | 4.5 kW | 47.73 dB | 4.3 | 4.15 | 4.5 / 2.5 | AAC7261 |
| Mitsubishi Heavy IndustriesDXK_20+2 variants | 2 kW | 2.7 kW | 49 dB | 4.75 | 4.73 | 4 / 3.5 | AAC8734 |
| Mitsubishi Heavy IndustriesDXK06ZSA-WF+1 variant | 2 kW | 2.7 kW | 49 dB | 4.73 | 4.71 | 4 / 3.5 | AAC7741 |
| Mitsubishi ElectricMSZ-GS25VFD+1 variant | 2.5 kW | 3.1 kW | 49.5 dB | 4.12 | 3.89 | 3 / 3 | AAC9097 |
| Carrier42QHB090N8-1 | 9.1 kW | 10.1 kW | 51 dB | 3.51 | 3.48 | 3.5 / 2 | AAC8823 |
| Mitsubishi ElectricMSZ-AP20VGD+1 variant | 2 kW | 2.5 kW | 52 dB | 4.32 | 4.14 | 3.5 / 2.5 | AAC8766 |
| Mitsubishi ElectricMSZ-AP20VGD+2 variants | 2 kW | 2.5 kW | 52.4 dB | 4.32 | 4.14 | 4 / 2.5 | AAC9073 |
| Carrier42QAF020N8 | 2.05 kW | 2.37 kW | 52.94 dB | 4.63 | 4.63 | 4.5 / 3 | AAC9368 |
| Carrier42QRF020N8 | 2.05 kW | 2.37 kW | 52.94 dB | 4.63 | 4.63 | 4.5 / 3 | AAC9459 |
Cooling and heating are rated capacity. AEER andACOP are the annual efficiency figures for cooling and heating — higher is cheaper to run. Stars are shown as cooling / heating for a mixed climate zone, which is the one Melbourne sits in. Indoor noise is the manufacturer's declared sound level for the indoor unit. Every figure is as registered with the Australian Government's GEMS register, and the registration number is there so you can look it up yourself.
The useful cut
Quietest in each size class.
Nobody buys the best unit in Australia. They buy the best one that fits the room. This is the same ranking applied inside each capacity class, so you can start from the size you need.
Read this before you decide on it
What the figure does not tell you.
Declared sound levels are measured by the manufacturer at a stated fan speed under test conditions. They compare like with like between models, which is what a ranking needs — but they will not match what you measure in your own room. Mounting height, the wall it is fixed to, hard floors and how close the bed is all change what you actually hear. A quiet unit badly positioned still sounds loud, and that is an installation decision rather than a purchase one.
All figures are read from the GEMS registration database (Australian Government) and each model carries its registration number, so any line above can be checked atthe register. Rankings change when manufacturers register new models.
Compare another way
Quietest air conditioners — common questions
What is the quietest split system air conditioner in Australia?
On the Australian Government's GEMS register, the lowest declared indoor sound level among wall-mounted single-phase reverse-cycle models is 47 dB, held by the Mitsubishi Heavy Industries SRK20ZTA-WF (registration AAC10044), a 2 kW unit. Sound figures are published for 363 of the models on the register. Bear in mind that the quietest unit overall is only useful if it comes in the capacity your room needs — the quietest model in each size class is listed further down.
How much quieter is a few decibels, really?
The decibel scale is logarithmic, so the difference is bigger than it looks. A 3 dB drop halves the sound energy; a change of about 6 dB is roughly what most people perceive as half as loud. So a difference between 47 and 53 dB on a spec sheet is not a detail — it is the difference between a unit you forget is running and one you notice every time it cycles.
Does the outdoor unit noise matter as much?
It matters to your neighbours and to you if a bedroom window faces it, and it is the part most likely to generate a complaint. The register publishes an outdoor sound level too, shown in the tables above. Positioning does more here than the specification does: an outdoor unit mounted on a hard wall that faces a neighbour's bedroom will be a problem no matter how well it rates, which is worth working out before installation rather than after.
The spec sheet picks the unit. A site visit picks the install.
Where the head goes, whether the board can carry it and whether one unit or two suits the room are not on any register. Yiannis will tell you, free of charge — ARCtick certified, REC 28523.