[77newell]

I always leave mine on overnight as the heater isn't that big and the block really is. I was also advised to turn it off prior to attempting a start to prevent any surge of air from passing over the heater and causing it to overheat and burn out. I will admit there have been times I forgot to turn it off and it still works. Still, I plan to turn it off as advised === when I remember, which gets less often the older I get.