AC sizing

Baseline: area × 30–40 W (exposure) + 100–120 W/person + devices. 1 BTU ≈ 0.293 W. Standard sizes: 7k, 9k, 12k, 18k, 24k BTU — take the next size up, an inverter will modulate down. +30% oversizing is fine for an inverter, but for on/off units — short cycles and humidity.