My school district switches to 4 ten-hour days over the summers; we save a ton of money on utilities just letting the buildings stay uncooled for three days ins

My school district switches to 4 ten-hour days over the summers; we save a ton of money on utilities just letting the buildings stay uncooled for three days instead of two. Nobody has suggested doing that when classes are in session, though. Probably because most of my administration is relatively sane.