This may be old news for some of you - I just was experimenting with the plug-in cold weather heater after replacing the electrical cord this fall (it burned through a part of the plastic grille before shorting out last winter). So I was reluctant to plug the new one in overnight when the temp went South (should be North) this winter. What I do now is plug it in in the morning when I first go out to feed the horses and it starts real easy when I'm ready to head to work in about an hour. No smoke or rough idling. This has worked well in temps around zero - hasn't gone below that yet - and saves a lot on the electrical bill.