If my memory serves me right, our previous bills were very similar. Back in May, the last full month before my main 18,000 BTU ac went down, the bills were 5842 and 5340 for you and me respectively. However, with the 2 new inverter ac's in the living room and mancave, I am detecting a significant advantage in my favour. Last month you were 4,661 against my 3,461 baht. Assuming our usage of electricity remains similar, and that this trend continues, it would suggest that my new 17,000 BTU + 10,000 BTU inverter aircons are cheaper to run than the 13 year old 18,000 BTU that they replaced. The mancave leads off the living room and previously did not have a discrete aircon. Cooling was indirect through the open door from the living room. Now both rooms have a discrete air conditioner.
My own elec bill was nearly halved once my own monster air con died. Also moved my bedroom from the huge room where the monster air con was into a smaller room with much newer air con. That old restaurant sized air con was very inefficient and was basically trying to cool off a double size room as well. So went from 6000 baht a month to 3000 baht a month. Big f**king difference and savings.