Free calculator
What size air conditioner do I need?
Enter the room and get the split system size we would expect to quote, worked out the way we size on site. Guide only; the free measure confirms it.
A split system is sized to the room's floor area, ceiling height, sun exposure and insulation, not to the number of people in it. In South East Queensland most bedrooms need 2.5kW, most living rooms 3.5 to 6kW, and a large open-plan kitchen and living area 7kW or more.
Your size will appear here
Enter the room, answer the five questions and press the button.
How we size on site
The calculator gets you close. The measure gets it right.
- The room, not the brochure
- We measure the floor, check the ceiling height, look at which way the glass faces and whether the roof space is insulated. The same inputs as the calculator, verified.
- The switchboard
- A 7kW unit needs a dedicated circuit and a board with the capacity to take it. We check before we quote so there is no surprise on install day.
- The outdoor unit
- Where it can go, how far the pipe run is, and whether it needs a coastal coating. All three change the price and sometimes the model.
- Two or three options
- You get a written quote with units around the calculated size, so you can compare brands and budgets rather than being sold one box.
Common questions
How accurate is this calculator?
It uses the same inputs we use on site: floor area, ceiling height, sun exposure and insulation, with a South East Queensland cooling load of roughly 130 to 175 watts per square metre. It will land you on the right size or one step either side. The free site measure settles it, because it also looks at the switchboard, the outdoor unit position and the pipe run.
Is a bigger air conditioner better?
No. An oversized unit cools the air quickly, switches off before it has pulled the humidity out, and cycles on and off all afternoon. In Queensland that leaves the room cold and clammy. An undersized unit runs flat out, never reaches temperature on a 35 degree day, and wears out early. The right size runs long, steady cycles.
What do the kW numbers mean?
The cooling capacity of the unit, not the power it draws. A 5.0kW split system removes 5kW of heat from the room while typically drawing 1.2 to 1.6kW of electricity. Heating capacity is listed separately and is usually a little higher.
Do I need a different size for Toowoomba?
Usually a step larger. Heating capacity drops as the outside temperature falls, and Toowoomba mornings in July are often near zero. We size Toowoomba units for heating, not just cooling, and choose models rated for low-temperature performance.
One big unit or two smaller ones?
Above about 8 to 9kW a single wall-mounted split system struggles to push air across a large open-plan space evenly. Two units, a multi-head system with one outdoor unit, or ducted with zones will give better coverage. We will tell you which after the measure.
Does the brand change the size?
Slightly. Sizes are nominal and vary by brand: Daikin and Mitsubishi Electric use 2.5, 3.5, 5.0, 6.0 and 7.1kW steps; Mitsubishi Heavy Industries and Fujitsu use similar steps with small differences. We quote two or three units around the calculated size so you can compare.
What our customers say
Reviews are pulled live from our Google Business Profile. Nothing here is edited or hand-picked.
Book a free measure and quote
Send the calculator result and the suburb. We'll come out, measure and quote in writing. No charge.
Or call 07 3108 4872, Mon–Fri 7am–5pm.