My modest Bangkok electric bill

At about ten cents US per kilowatt hour the electric bill for our condo was less than forty dollars US last month, a cool one. Our hot June bill (750 kw-hrs) was nearly double; even then our nightly use of aircon for a single shaded bedroom amounted to only about $1 extra a day -- not too bad. On the other hand, this would amount to perhaps ten percent of the income of most Thai workers -- making aircon a threshold luxury for them. 

This is also consistent with the observation that aircon amounts to roughly half the electric power use in Bangkok.