thanks Kevin - Is it intended to be used over night when cold, prior to a day of use?
If you like spending money on electricity, plug it in overnight. I have a block heater in my Diesel, and I use a timer to turn it on about 3 hours before I want to go somewhere, but only when it's cold enough to make your nose hairs freeze (happens below about 0F). A few hours should do it for you. Gas engines are usually pretty easy to start when it's cold out - Diesels not so much.