thisplace.com.au - Getting the Right Size Air Conditioner

Bedroom

A bedroom of 15 square metres ( 160 sq ft ) will need an air conditioner with a cooling and heating capacity of around 1650 watts (5600 Btu/hr).

An air conditioner that is to be used only in bedrooms overnight can be calculated on the basis of 110 watts pre square metre ( 35 Btu/hr) of floor area.

a rough guide for South East Queensland is - 140 watts per square metre ( 45 Btu per sq ft ) of floor space in daytime living areas - remember this is only a guide, seek professional advice when considering your air conditioning options

Living Room

An average living area of 25 square metres ( 270 sq ft ) will need an air conditioner with a cooling and heating capacity around 3500 watts ( 12150 Btu/hr ).

Air conditioners are rated by their cooling or heating capacities in watts or kilowatts. This, the rate of heat transfer, is not to be confused with the energy input to the air conditioner ( 1 watt = 3.412 Btu/hr ).

Source : from Advair website