How do I determine the correct size of a rooftop unit (RTU) for my building?

To determine the correct size of a rooftop unit (RTU) for your building, you need to calculate the total cooling or heating load required. This involves considering factors such as the building’s size, occupancy, insulation, window orientation, and climate zone. You can use industry-standard calculation methods, such as the Air-Conditioning, Heating, Refrigeration Certification Board (ACHR) method or the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) method, to determine the required tonnage or BTU capacity of the RTU. Oversizing or undersizing the RTU can lead to energy inefficiencies, comfort issues, and reduced equipment lifespan.