I can see this working - as long as your heat never fails, or you do not get an ice storm that knocks out power for a week. There are periods of time where I live that if you lose power for even a couple of days you can have problems.
Back to the OP situation. What would happen if he got sick or was in an accident and could not check on the house? That is why I said do it all the way or just let the heat on.
In a house that I used to own which was reasonably well insulated I had a couple of pipes freeze that ran up inside of an outside wall when the inside heat was at 70 degrees.
Plus I have come to expect the unexpected, so I prepare for it. As I stated opinions vary. I have learned the hard way what works for me. I got tired of cleaning up messes and getting my pocket book emptied by doing things half a****. To each his own, I have no stake in the game. I was just trying perhaps to save someone from some problems.