Portable air conditioning units are easily moved appliances used to cool a room. British Thermal Units are the amount of heat an AC unit can remove from a room. One BTU is the amount of heat required to raise 1 pound of water by 1 degree Fahrenheit.
It is normally accepted that for an air conditioning unit to remove heat from 1 square foot it must have a capacity of at least 30 BTU. In order to asses whether a 14,000 BTU AC unit is sufficient, multiply the room's square footage by 30. A 14,000 BTU unit can cool a room between 500 and 700 square feet, according to Lowes.