usually only use fans in windows blowing air in and out at night, most nights still cool off to lower 70's or so. Then in morning close up house and stays fairly cool most of the day.
I think we call those electric heat pumps in the US. They're popular in the South, but not practical where it gets really cold. I had one when I lived in Virginia and it had a backup electric heater for when the temperature got much below freezing outside.
Luckily I stay in a warm country, it only gets cold here at night now here in July mid winter, but the days are really warm we can walk with short and T-shirts during the day and by the middle of August it starts warming up quickly again for spring. Someone told me once that we don't have spring here, it goes straight to summer from winter.
Have a nice day !
Plus, they have box fans.