There is no silver bullet answer this problem, however it is very important to ensure that the correct base, little research can save a lot of money.
First of all, the ability of air conditioning is cool room or living space. Capacity in the United States, usually in British thermal units (BTU) or "tons", according to the climate of your area, building design, facing the direction and material, choose the capacity of the air conditioning unit.
What is the BTU?
British thermal unit or BTU is the basic unit of the HVAC and other industries. A total of 12000 BTU per hour the refrigerating capacity is equal to 1 ton refrigerating capacity.
What is the cooling tons?
Before refrigeration, ice maker usually use BTU to measure their energy demand, an estimated 288000 BTU within 24 hours, to produce 2000 pounds or one ton of ice.
Therefore, every tons of ice need 12000 BTU per hour (288000/24 = 12000 BTU).Therefore, the word "tons" is usually used in refrigeration or air conditioning performance.
Therefore, when we talk about a rated for 1 ton or 2 tons or 3 tons of air conditioning unit, means the BTU energy required, so that the cooling volume reached 12000 times of the rated capacity.You may see that you buy air conditioning the ratings are printed on the nameplate, whether it's with a ton or BTU.