Flooding your room with natural light is all well and good – but at what cost? Direct sunlight will heat up your room even more, so by closing the curtains you're blocking off the worst offender. Your next step should be to open up your windows to allow the air in your home to circulate. Nobody wants a stuffy house, and on the off chance that there's a cool breeze outside, you'll want to catch some of it indoors. And, to aid the airflow, keep the internal doors of your house open (not the external doors – you want to avoid being burgled). As long as you trust your housemates, keeping your bedroom door slightly open overnight should help you keep cool while you sleep.
