12 Mar 2018
It's a good habit to open windows regularly every day to let in fresh air. The best time to do so is believed to fall between 9 and 11 am, or 2 and 4 pm. Usually, an hour or so would be long enough to change the air indoors for the whole day. Some people keep the bedroom window slightly open even at night, and this is certainly not a bad habit, since most bedrooms are more of a tight enclosure during sleeping time.