You will find that in Thailand, even if you own your own house, the biggest monthly expense will be electricity.
Some expats are able to live without air conditioning by using fans, however, if you want to remain cool the same as you did in the west, the electric bill will be driving the cost.
If you run the air conditioning all day, as well as all the other western conveniences such as a washer and dryer, double refrigerator, freezer, electric stove, big screen tv, computers, etc. it is not uncommon to have an electric bill over 6,000 to 8,000 a month. (Still cheaper than the west for the same conveniences).
There is also lighting and any outdoor amenities such as well pumps and even pool pumps.
If cost is a factor to you, there are low-cost single solar solutions to power an item such as a well pump.
There are also entire house solar solutions (Do the research over the long term including the cost of replacing the solar components at some point in the future and if the replacement costs will be higher).
Each household has their own electric requirements, however, to maintain the same standards, the cost will be in range mentioned above.