divide rated cooling output by rated power input, in pak, we generally use w/w, in some regions, btu/w is used
like incase of 2 Ton T3 pro cooling.
rated btus are, 24000
convert but to watts, 12000 btus= 3517 watts
hence 24000 btus= 3517*2= 7034 watts
so the cooling capacity is 7034 watts
rated power is 2000 watts
7034/2000= 3.517 w/w
attaching sticker for better understanding
if someone is confused about why we are using watts rather than btus, at the end of day, it's energy, you can use units like BTU, watts, Kw, Hp or Kj/h
in fact all these units are globally used in different regions for acs