On non-Inverter ACs, I only need to use the power input (e.g. 800W) to calculate my energy cost for a 12-hour usage. (800*12/1000 = 9.6kW-hr)
On Inverter ACs though, I know they don’t operate at 100% all the time, and most of the time the only information I get is their cooling capacity (e.g. 1hp ≈ 746W) and their EER (e.g. 12.2 kJ/hW).
How do I use these to get a rough estimate of the energy cost?
Depends on your cooling requirements? Full blast it is the same as before. Anything less proportionally less.