In several recent energy audits of older elementary schools in Utah we found out why we froze to death as a child sitting in those classrooms. No wonder we wore jackets while sitting at our desks.
Even before we started the huge blower door fans to depressurize the building we noticed how cold the entire windowed walls were. These schools are retrofitting and installing new triple pane energy efficient window systems. The results are outstanding - not only is the draftiness gone, but the windows are blocking out the chilling outside temperature. Two particular classrooms had "zero" insulation on the north side walls. The entire block wall was "blue" or cold.
In the thermal images - the blue is cold and red colors warm.