The question is a double edge.
1. How hot is the room when you start the aircon.
2. What other heat sources are there in the room generating heat. Electrical lighting, electrical equipment, electronic apparatus, direct sunlight on walls and through windows.
3. What temperature is 'cool'?
4. What materials are in the room made from, as they could be absorbing the cool air, and not passing it on to the room. Typical is mortar
5. What is the relative humidity, as this affects the efficiency of the aircon
6. What is the ambient temperature of the outside evaporator, as this affects the efficiency ability of the aircon

Human bodies generate approximately 300w of heat per hour, so must be taken into consideration

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