Quick Tip if your windows and doors open – at the VERY LEAST, open during breaks and lunches. Source:
“If its cold, crack the windows rather than opening them fully and then open them wider to air the room periodically say at break times. The colder it is, the smaller the gap you need for ventilation. And let them layer up too.
Ventilation is driven by pressure differences and they are created by temperature differences (hot air rises) and wind. So for the same size gap you get more flow when there is a bigger temp difference between indoor and outdoor or there’s a higher wind speed.
So a fairly small gap in winter can give you as much ventilation as fully open window in summer. It is hardest to ventilate when its a warm still summer day with no difference in temperature and no wind.”
Some recommended ways to help with natural ventilation from the CIBSE Natural Ventilation Chair.
Original Source is here – 41 pages of great information. But if you have no time, here’s the most relevant 4 pages to you or me, the common person. Some samples below:
“Openable windows and vents should be used more than normal, as long as security is
considered and the open windows do not cause a hazard to anyone moving outside. If
possible windows should be open at least 15 minutes prior to room occupation.“
“In cooler weather even a small opening can deliver significant ventilation flows, and this can minimise risk to occupants of the space.”
“Where there are both high-level and low-level openable windows in a room, it is
recommended to open the high-level windows during cooler weather in the first instance; incoming air will be warmed as it flows down into the room, thereby reducing cold draughts.”