What size air conditioner do you need for a 625 SQ FT room?

Answer 1

how cold do you want it? 9,000 btu minimum, and about 18,000 maximum. higher btu=colder temperature, shorter cycles to cool a room down, but more energy usage while running. hotter environments or poor insulation, or hot running electronics will make the unit work harder, so if anny of these conditions apply, go for a bit higher than the 9,000 minimum

Answer 2

A room size of this size would take a 5600 BTU air conditioning unit. This can be purchased at most home improvement retailers.