As a "rule of thumb", room sizes between 300 to 450 square. ft. can be cooled by portable units ranging from 8000 to 10,000 Btu while room sizes between 350 to 550 sq. ft. can be best satisfied with units your past 12,000 to 16,000 Btu range. Described earlier, in addition to room size, additional heating factors in the room need to become taken into mind. These factors include are usually no