I have a 150 gallon glass tank in my garage in Fremont. I have 750 watts of heating capacity and have never had a problem with the water temperature. If you kick it up to 5 watts/gallon during the winter, I really don't think you need the foam. Also, bear in mind that the filter motor will add some additional heat. 5 watts/gallon consumes very little power.
Because it doesn't get REALLY cold here we dont have central heating, so when we do get cool weather we just tough it out. Might get ice on the inside of the windows a few times a year. No problemo.