A 3 ton rooftop packaged unit is a self-contained heating and cooling system that is installed on the roof of a building. It is a great option for commercial and industrial applications that require a large amount of cooling or heating power. The unit is composed of a compressor, condenser, evaporator, and other components that work together to regulate the temperature of the building. The unit is typically rated in tons, which is a measure of the amount of cooling power it can provide. A 3 ton unit is capable of providing up to 36,000 BTUs of cooling power, which is enough to cool a space of up to 1,500 square feet. The unit is also highly efficient, with an Energy Star rating of up to 18 SEER. This makes it a great choice for businesses looking to reduce their energy costs.