# Why is the capacity of the air conditioner (AC) measured in tons?

One of the most confusing terms in the air conditioning industry is “ton”. For an air conditioner, the word does not refer to weight. Instead, a ton of ice refers to the amount of heat required to melt completely. Shows how many British Thermal Units (BTUs) can remove heat from an air conditioning system.

1 ton is equal to 2000 lb (lb is the symbol for the pound). The latent temperature of ice is 144 BTU / lb (BTU is the British thermal unit). This means that when 1 pound of ice starts to melt, it will absorb 144 BTU of heat.

So 1 ton of ice or air conditioner absorbs 2000 Γ 144 = 2,88,000 BTU of heat in 1 day.

Divide the above by 24 to absorb the heat within 1 hour.

2,88,000 24 = 11,917 Btu / hr
Rounding up gives you 12,000 Btu / hr, or 12,000 BTU / hour.

This means that 1 ton of air conditioner or ice absorbs 12,000 BTU in 1 hour.

Similarly, a 4 ton air conditioner absorbs 4 Γ 12,000 = 48,000 BTU of heat per hour.

Therefore, as the ton of air conditioner increases, it can absorb more heat and cool more air.

Before Willis Carrier invented the modern air conditioner, people used to cool buildings in the summer with ice collected from rivers and lakes.
Ice Harvest West is a business that originated in the United States in the 1800s. This means that many lakes freeze during the winter. The resulting ice is cut into large blocks with large swords and stored in a warehouse insulated with sawdust, which is then sold to warmer areas. This ice was used to cool homes and hotels in hot weather. By the 1920s, machine-assisted refrigeration was in vogue, and by the 1950s, the business was almost complete.