As a rule of thumb: small bedrooms suit around 2.5kW, large bedrooms and studies around 3.5kW, open-plan living areas anywhere from 5kW to 8kW depending on volume, glazing and orientation.
Newcastle's humidity matters too - on muggy February nights an oversized unit that short-cycles will leave the room cold but damp. Right-sizing gets temperature AND comfort right.
Not sure? Send us your room sizes through the free online quote and we will do the maths with you.