I am not in a market that freezes so I am truly asking out of curiosity...Why 55? 

I can put the hot water heater in vacation mode and it will keep it at 50F to prevent freezing.

I've had some pipes freeze before, they burst and leak. 

@Sean MillsI see nothing in that link as concerning...All it details is that the CRA can freeze the assets of tax evaders, including real estate in Canada and abroad.What isn't mentioned and is concerning is the "how" not the "what". 

With cold weather, pipes may freeze up.

@Stephen E.Your garage must be heated, otherwise your lucky the water left in the dishwasher didn't freeze.  

Winterizing is cheaper but when you show a vacancy in the winter you want it to be warm inside not freezing cold.  

I think the holiday lull and elevated interest rates are freezing the market in my area. 

Heaven is expensive:) When they are freezing up in the north we will be riding around in our convertibles wearing shorts and drinking iced tea:) When the right deal comes along, I can pull 100% out of the house posted above if needed and yes, returns are infinite. 

I would probably put a strong blower fan down there for a few days or a week just to dry things out at first but see no reason why you would need a fan down there permanently.I'm in a cold climate so my vents have to be closed in the winter or pipes can freeze.