my 10 x 12 shed is not insulated, I also keep a fan up against an open window for exhaust. It was un workable to wet grind 20 deg. or below. I bought a cheap little heater that connects to the top of my grill's propane tank. I just bundle up and use the heater to keep my hands warm...It is fine now even for grinding wet. I turn my grinder on low speed with no belt to let it warm up a bit before I go full blast. I have no idea if this is necessary or not. A nice insulated thermos of black coffee helps too. Two pairs of wool socks and thinsulate ll bean boots gives me about 2 hours before the toes are too cold

I will take this over grinding in the heat of summer. It can be awful difficult holding steady with steel and fresh ceramics at high speed, while sweat is dripping into your eyes and mosquitoes are biting any bit of bare skin...lol