Air conditioning
Wednesday, April 28, 2010
1:02 PM
Cooling
Air conditioners are rated in BTU/hour (i.e., in power units!).
For a machine room to be at a stable temperature, 
the rating of the air conditioner (in cooling BTUs) must be greater than the rating of the equipment (in heating BTUs).
HVAC (Heating, Ventilation, Air Conditioning) people use the power input to a room to measure what cooling it needs: if it has 40 amps coming in, then it needs at least 120V*40A= 4800 W = 16,378 BTU/hour.