Loading ...So turn your house into an airconditioner. Spray water on the roof and sunniest walls. It doesn’t need much, you aren’t trying to cool the house with cold water, but by evaporation of the water, so ideally you don’t want any run-off. Absorbent tiles like terracotta are best because they will hold water for a while, although it works fine on painted concrete tiles too. If the gutters are easily accessible draping silver tarpaulins from them for shade makes a huge difference too. Just be ready to take them down quickly if a summer storm build up.
If you put in ducted aircon upstairs, the evaporator is in the roof and you can let the cold air percolate down from the bedrooms and stairwell, with the condensor situated almost anywhere outside connected by piping identical to a rainwater downpipe.