I suspect that I'll never see "summer-like" MPG, but it will be better than starting at ambient temp in the winter! I've been told to heat it for 3-4 hours, so we're setting a timer to go on about that amount of time before the anticipated morning drive time. My car can get 30MPG in the summer, but was at about 19 in the winter so I hope to bring it up into the 20's with the heater.

I'm a "worst-case" driver - no garage, and only about a 5-mile commute. I never even got the car warmed up last winter on the drive into work, so I think this will help. I'll let you all know!