If you rely on open windows for good ventilation in your classroom, you will need to keep a few windows cracked open a few inches even though it's getting colder. The good news is you can open fewer windows because of the laws of physics.

The temperature difference between warm air inside and cold air outside actually creates better movement of the air. The colder it is outside, the better the air exchange! 

For best results:

• Open two to four windows from the top about 3 inches.
• Have the custodial engineer check the temperature and carbon dioxide levels in your classroom if it’s just too cold to leave windows open that amount.
• Keep the top and front of radiators clear to allow proper heat circulation.

For questions about building temperature or your school's ventilation system, see your chapter leader or call the UFT at 212-331-6311.