BTU in practice: sizing the air conditioner for a room

Before you buy an air conditioner, you need one number: how much heat enters the room per hour. This course teaches that number without memorizing. You will understand how the split unit takes heat from inside and throws it outside, what BTU/h, kW and TR mean on the label, and how to calculate the heat load of a room with a simplified, step-by-step method and a complete worked example. Then you use the free BTU calculator on the e-nogueira.com.br website with judgment: you see the calculation it does inside, read the electrical and consumption estimate it returns, and recognize what it cannot see. Finally, you compare inverter and fixed-speed units, high-wall, cassette and floor/ceiling types, read the efficiency label and understand the refrigerants R-410A and R-32. The course closes with the real cost of undersizing or oversizing and a list of what to ask the installer. It is for people who are about to buy and for people starting out in refrigeration. It does not replace the design of a large HVAC system or professional qualification.