Size the air conditioner correctly

A rough guide to make sure you fit the correct size air conditioner to the area which you want to cool is to apply the 500btu's per square metre formula. This is provided the ceiling height is standard 2,4 metre in height, and there are no north facing windows or glass doors. Other heat producing elememts must be taken into account, ie computers, lights, machinery and amount of people (working or at leisure) By installing the wrong size air conditioner may be cheaper initially but will cost more in the long run. Electrical running costs will be more because the compressor will run indefinitely trying to cool or heat an area that is too big. The units will often freeze up and cause damage or excessive compressor wear. Also consider that if you size an air conditioner for a certain area, the doors and windows need to be kept closed as much as possible. In cases where it is not possible to keep doors closed an air curtain should be used. Running costs of air conditioning in buildings generally equates to 30% so it is worth considering the sizing carefully to optimize your energy consumption and maintenance costs. 

A rough guide is as follows:

 9000btu - 18M2

12 000btu - 24M2

18 000btu - 36M2

24 000btu - 48M2

30 000btu - 60M2

 General Air Conditioner Information