An air conditioner British thermal unit, or BTU, chart typically includes the square footage of the area to be cooled and the recommended number of Btu required. The chart may also include information on refinements to the base capacity to arrive at a more accurate estimate.
Based on the size in square feet of the area to be cooled, an air conditioner BTU chart suggests the recommended air conditioner capacity in British thermal units. In addition to suggesting a base capacity, some charts include information to help homeowners make adjustments specific to their environments. These adjustments can include the amount of sun or shade the area receives, the number of people that generally occupy the area and whether the area is a kitchen.