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Cooling load calculator

Get a quick estimate of the cooling capacity a room needs — and a suggested air-con size — from its area, occupants, equipment and sun exposure.

The room
Size, use, occupancy and sun exposure.
Estimated cooling load
5.2 kW
For 30 m² of living / lounge with 3 people — a unit around 6.0 kW would typically suit.
Base load (area)4,200 W
People360 W
Appliances600 W
Total cooling load5.16 kW
Suggested unit size~6.0 kW

Rule-of-thumb estimate only. A proper cooling load calculation accounts for climate, insulation, glazing, orientation, ceiling height and infiltration — size critical jobs with a full method.

Quoting the install? traqR turns your sizing into a quote, job and invoice, with the unit and materials on the one job card.

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How it works

1

Start with the room

A base heat-load allowance per square metre, set by the room’s use, gives the bulk of the cooling load.

2

Add the gains

People and equipment each add heat. Occupants contribute around 120 W each, and appliances and lighting add their own load.

3

Adjust for sun

Rooms with lots of glass or direct sun need more cooling, so the total is scaled up for exposure before suggesting a unit size.

Frequently asked questions

How do I size an air conditioner for a room?

A quick estimate multiplies the floor area by a heat-load allowance per square metre for the room type, then adds heat from people and equipment and adjusts for sun exposure. For a typical 30 m² living room that lands around 5–6 kW. This is a starting point — proper sizing uses a full load calculation.

What is cooling load measured in?

Cooling capacity is measured in kilowatts (kW) of heat removed. Air conditioner nameplates quote their cooling capacity in kW; matching that to your calculated cooling load is how you avoid an undersized or oversized unit.

Why not just go bigger to be safe?

An oversized unit cools the air quickly but short-cycles, so it doesn’t run long enough to remove humidity, leaving the space cold and clammy, and it wastes energy and wears faster. Right-sizing gives better comfort and efficiency than simply going large.

Is this accurate enough to design a system?

No. It’s a rule-of-thumb estimate for budgeting and sanity-checking. Detailed system design should use a recognised load-calculation method accounting for climate, building fabric, glazing and ventilation.

This calculator is a rule-of-thumb estimate for guidance only. Accurate cooling load and equipment selection require a full calculation accounting for climate, insulation, glazing, orientation and ventilation, carried out by a competent HVAC designer or installer.

Quote the install in minutes

traqR turns your sizing into a quote, job and invoice with the unit and materials on one job card. Try it free for 14 days.

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