what do you do when the weather is very hot?
if it is cold it will be very easy to make it warm, but if it's hot it is a little difficult to make it cold. So, what do you usually do?
Based on your premise and example, it seems that you live in a cold weather climate, that's why you seem to have no idea about how it is if you live in a hot or tropical weather climate.
Nonetheless, for hot or tropical weather climate, it's either you turn-on the airconditioning, turn on the electric fan and/or you may use an exhaust fan to further assist letting out the hot air inside your home, or simply open your windows for better ventilation instead.
Bottomline, it all boils down to cost, whether or not you have any of the above options I've mentioned.