I know the pains.

I installed a roof ventilator (whirly bird - a small dome-like spinner which draws hot air out and the eaves under the roof let cool air come in). The whirly bird works by air circulation --no electricity--. A couple units  cost much less than an air conditioner and electricity (in Aus a DIY unit costs < $50). But my high pitch roof and ceiling are well suited for the this type of cooling. Some roofs have no air circulations and they act like thermal storage -- keeping heat in the house.

BTW, try grow one or two หองอุไร --away from the house--. They are hardy, fast growing, semi-shade trees. Their roots will break up hard soils --and even produce sucklings--. They have beautiful flushes of yellow flowers. And they may even keep termites and mossies away. ;-)