How to Choose the Right Size Split System Air Conditioner

How to Choose the Right Size Split System for Your Brisbane HomeOne of the most common mistakes we see in Brisbane homes is a split system that's the wrong size for the room. Too small, and it runs constantly without ever quite cooling the space. Too big, and it cycles on and off, wasting energy and leaving the room feeling clammy.
Why size matters more than brand
A well-known brand won't fix a poorly sized system. Capacity, measured in kilowatts (kW) of cooling output, needs to match the room — not just its floor area, but its ceiling height, insulation, window size and which direction it faces.
Rough sizing guide for Brisbane rooms

• Small bedroom (10–15m²): around 2.5–3.5kW
• Living room (20–30m²): around 5.0–6.0kW
• Open-plan living/dining (35–50m²): around 7.0–8.5kW

These are starting points only — a west-facing room with lots of glass will need more capacity than a shaded, well-insulated one of the same size.
Why a proper assessment beats a rule of thumb
Brisbane's humidity and long, hot summers mean undersizing is a common and costly mistake. We measure the room, check insulation and orientation, and size the system to run efficiently rather than flat-out all day.
Thinking about a new split system? Manta Ray Electrical installs single and multi-head split systems across Brisbane. Get in touch for a free assessment and quote.