In air conditioning specifications, the term "1.5 ton" refers to the cooling capacity of the air conditioner. It is a measurement of the unit's ability to remove heat from a space.
Traditionally, the cooling capacity of air conditioners was measured in tons, which originated from the time when large ice blocks were used to cool buildings. One ton of cooling capacity was equivalent to the amount of heat required to melt one ton (2,000 pounds) of ice in 24 hours.
In modern air conditioning systems, the tonnage refers to the cooling capacity rather than the literal weight of ice. A 1.5-ton air conditioner is designed to remove the amount of heat equivalent to what would be required to melt 1.5 tons (3,000 pounds) of ice in 24 hours.
The cooling capacity of an air conditioner is typically expressed in British Thermal Units (BTUs). To convert the tonnage to BTUs, a general rule of thumb is to multiply the tonnage by 12,000. Therefore, a 1.5-ton air conditioner would have a cooling capacity of approximately 18,000 BTUs per hour (1.5 tons * 12,000 BTUs/ton).
It's important to note that the cooling capacity required for a particular space depends on various factors such as the size of the area, insulation, climate, and heat-generating sources. Consulting with an HVAC professional can help determine the appropriate cooling capacity needed for your specific needs.