Yes, when cold out we just plug it in when returning from a drive and it keeps cyl head warm to the touch and the temp gauge will go up 1/4 way when starting but when started it comes rite back down as the coolant does not get heated,shorter warmup like one block compared to a mile unplugged. have seen wind chills in the -20 below for a week. I just think it is easier on the ICE.

TCH-43mpg
VW TDI--48
08 LS 600 HL-20
08 LX 470-16