2.5 kW class
2.5 kW split systems, compared on the figures that matter.
A 2.5 kW unit typically suits a bedroom, study or home office — roughly 11 to 23 square metres depending on which way it faces, how well it is insulated and how many people use it. 96 models in this class are registered for sale in Australia across 8 brands.
Quick answer
A 2.5 kW split system air conditioner suits a room of roughly 11 to 23 square metres — typically a bedroom, study or home office — with the exact figure depending on orientation, insulation, ceiling height and occupancy. 96 distinct 2.5 kW-class models are registered with the Australian Government's GEMS database across 8 brands: Carrier, Daikin, Fujitsu, Hisense, Mitsubishi Electric, Mitsubishi Heavy Industries, TCL, Teco. In this class the best cooling efficiency figure is AEER 6.25 and the best heating efficiency figure is ACOP 5.95, and the lowest declared indoor noise level is 47 dB. Thunderman Electrical and Air Conditioning Services supplies and installs units in this class across Greater Melbourne under ARCtick certification, with electrical work by REC 28523.
What this size means on the job
The part a showroom won't tell you.
The 2.5 kW class is the most crowded on the register, and for a reason: it is the size that suits a bedroom, a study or a home office, and it is usually the first split system a household puts in. Electrically it is also the easiest — a unit this size will generally run on a dedicated 10 amp circuit, so on a board with a spare way and reasonable capacity it is a straightforward job. The trap at this size is not the unit, it is the assumption that a small unit means no switchboard work. A 1960s or 1970s board with ceramic fuses and no spare ways still needs attention before anything gets added to it, and that is worth knowing before the unit is chosen rather than on installation day.
Quietest in this class
Ranked by declared indoor noise.
In this class the declared indoor noise levels run from 47 dB to 59.2 dB — a spread of 12 dB between the quietest and the loudest, which is a difference you would hear plainly in the same room.Capped at three models per brand so one range cannot fill the table.
| 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 |
| 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 |
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.
Cheapest to run — cooling
Ranked by AEER.
Cooling efficiency in this class runs from AEER 3.55 to 6.25 — the best unit here delivers about 76% more cooling per unit of power than the weakest. That gap is what you are choosing between, and it does not show up on the star sticker, because stars are banded.
| Model | Cooling | Heating | Indoor noise | AEER | ACOP | Stars | Registration |
|---|---|---|---|---|---|---|---|
| Mitsubishi Heavy IndustriesSRK20ZSXA-W | 2 kW | 2.7 kW | 53 dB | 6.25 | 5.63 | 4.5 / 4 | AAC8729 |
| Mitsubishi Heavy IndustriesSRK20ZSXA-WF | 2 kW | 2.7 kW | 53 dB | 6.22 | 5.61 | 4.5 / 4 | AAC7747 |
| Mitsubishi Heavy IndustriesSRK25ZSXA-W | 2.5 kW | 3.2 kW | 55 dB | 5.56 | 5.33 | 4.5 / 4 | AAC8728 |
| DaikinFTXM25W2VMA | 2.5 kW | 3.2 kW | 57 dB | 5.3 | 4.95 | 5.5 / 3.5 | AAC6754 |
| DaikinFTXM25YVMA | 2.5 kW | 3.2 kW | 57 dB | 5.3 | 4.95 | 5.5 / 3.5 | AAC7604 |
| DaikinFTXM25AVMA | 2.5 kW | 3.2 kW | 57 dB | 5.27 | 5.57 | 5.5 / 4 | AAC10031 |
| TCLVAIH+3 variants | 2.8 kW | 2.65 kW | 47.73 dB | 5.11 | 5.54 | 5 / 3.5 | AAC8101 |
| TCLIH+5 variants | 2.8 kW | 2.65 kW | 47.7 dB | 5.11 | 5.54 | 5 / 3.5 | AAC8485 |
Best for a Melbourne winter
Ranked by ACOP — the heating figure.
Heating efficiency here runs from ACOP 3.78 to 5.95, a spread of about 57%. Because Melbourne runs a reverse-cycle system for warmth far more of the year than for cooling, that spread costs more over time than the cooling one does — and this ranking is rarely the same as the one above it.
| Model | Cooling | Heating | Indoor noise | AEER | ACOP | Stars | Registration |
|---|---|---|---|---|---|---|---|
| DaikinFTXM20AVMA | 2.2 kW | 2.7 kW | 55 dB | 5.25 | 5.95 | 5.5 / 4 | AAC10030 |
| Mitsubishi Heavy IndustriesSRK20ZSXA-W | 2 kW | 2.7 kW | 53 dB | 6.25 | 5.63 | 4.5 / 4 | AAC8729 |
| Mitsubishi Heavy IndustriesSRK20ZSXA-WF | 2 kW | 2.7 kW | 53 dB | 6.22 | 5.61 | 4.5 / 4 | AAC7747 |
| DaikinFTXM25AVMA | 2.5 kW | 3.2 kW | 57 dB | 5.27 | 5.57 | 5.5 / 4 | AAC10031 |
| TCLVAIH+3 variants | 2.8 kW | 2.65 kW | 47.73 dB | 5.11 | 5.54 | 5 / 3.5 | AAC8101 |
| TCLIH+5 variants | 2.8 kW | 2.65 kW | 47.7 dB | 5.11 | 5.54 | 5 / 3.5 | AAC8485 |
| Carrier42QCE020N8+3 variants | 2.15 kW | 2.45 kW | 55.11 dB | 4.83 | 5.37 | 5 / 3.5 | ZAC0838 |
| DaikinFTXM20W1VMA | 2.2 kW | 2.7 kW | 55 dB | 5.22 | 5.33 | 5 / 3.5 | AAC6481 |
Not sure this is the right size?
Look either side.
All figures from the GEMS registration database (Australian Government). Every model above carries its registration number so you can check it atthe register.
2.5 kW air conditioners — common questions
Is a 2.5 kW split system enough for a bedroom?
For a typical Melbourne bedroom, usually yes. The published sizing rule of thumb is around 150 watts per square metre, adjusted for which way the room faces, how well it is insulated and how many people are in it — which puts a 2.5 kW unit somewhere between roughly 13 and 23 square metres depending on those factors. A west-facing, poorly insulated room sits at the small end of that range; a south-facing, well-insulated one at the large end.
How many 2.5 kW models are sold in Australia?
96 distinct models in this capacity class are currently registered with the Australian Government's GEMS database, across 8 brands: Carrier, Daikin, Fujitsu, Hisense, Mitsubishi Electric, Mitsubishi Heavy Industries, TCL, Teco. That count is registrations rather than shelf listings — a single registration often covers several colourways of the same unit, which is why a retailer's catalogue looks larger.
What is the quietest 2.5 kW air conditioner?
The lowest declared indoor sound level in this class is 47 dB. Noise figures are declared by the manufacturer at a stated fan speed, so they compare like with like between models but will not match what you measure in a room — where the mounting position, the wall and the furnishings all change what you hear. A unit that is quiet on paper and badly positioned will still be the loudest thing in a bedroom.
Does a 2.5 kW unit heat as well as it cools?
Not necessarily, and in Melbourne that is the question worth asking. In this class the best cooling efficiency figure (AEER) is 6.25 and the best heating figure (ACOP) is 5.95, and they usually belong to different models. Because a reverse-cycle system here runs for warmth far more of the year than for cooling, the heating figure generally deserves more weight than the cooling star rating a showroom will point at.
Right size, wrong switchboard is still the wrong job.
Yiannis will confirm the capacity against the actual room, check the board can carry it, and quote the whole job rather than the easy half. Free quote, ARCtick certified, REC 28523.