Why BTU and EER matter
BTU per hour describes cooling capacity. EER compares that cooling output with electrical input at a specified test condition. Dividing BTU/h by EER gives a useful estimate of running watts for a room or window unit.
Runtime is not the same as compressor time
An air conditioner may be available for eight hours without drawing full compressor power for all eight. The runtime percentage lets you model cycling. Hot weather, direct sun, air leakage, poor sizing, and a dirty filter can increase that percentage.
For central and inverter systems
Variable-speed and central equipment needs a more detailed model using seasonal efficiency, capacity stages, climate, and measured consumption. Use this result as a planning estimate, not a load calculation or equipment-sizing recommendation.