What Size Air Conditioner Do I Need? Free Sizing Calculator
Undersized air conditioners run flat-out and chew through power. Oversized units short-cycle, wear out faster and leave rooms clammy. Getting the kilowatts right is the single most important decision in any aircon purchase — and it takes less than a minute. Enter your room measurements below and our calculator will recommend the right split system, multi-split or ducted size using the same capacity rules our installers apply on every Efficient Energy Group quote..
Air Conditioner Sizing Calculator
Enter your room sizes and get a recommended system size in seconds — split, multi-split or ducted. Free, no signup.
How to measure your room: measure length and width in metres at floor level and multiply them — a 5m × 4m bedroom is 20m². For L-shaped or open-plan spaces, split the area into rectangles and add them together; if your kitchen flows into the living room with no door, the air does too, so measure the whole connected space. As a rule of thumb, allow roughly 130 watts per square metre: a 16m² bedroom suits a 2.5kW unit, a 30m² living room around 4.2–5kW, and a 50m² open-plan area 6–7kW. High ceilings, west-facing glass and poor insulation push the number up — the calculator adjusts for all three.
The right size also means the right rebate. Government energy schemes in NSW, VIC and SA take hundreds to thousands off high-efficiency reverse cycle systems — and higher-efficiency units earn bigger discounts. Check what your postcode qualifies for in 30 seconds with our air conditioning rebate checker — then talk to our team about a fixed-price installed quote.