We have a summer home on the NJ coast that sits on top of an unheated crawl space, (2' high). There are 4 vents into the crawl space. The copper plumbing pipes run throught the crawl space. No heating duct work at all is in the crawl space.
We have NEVER kept the house open in the winter, (i.e. water off, pipes drained, etc.). This winter we will need to keep the house open. I have been making several modifications to prevent the water pipes from freezing in the crawl space.
So far I have installed a new gravity flow wall furnace, (not the best for keeping floors warm), and insulated all water pipes in the crawl space. I plan on keeping the house temperature at 65 degrees minimum to hope that the hard wood floors will transmit enough heat to the crawl space to prevent pipes from freezing. I will also close off the vents once the cold weather approaches.
** HERE IS MY NEXT THOUGHT: I was thinking about installing a bathroom ventillation fan on the main level in the living room and venting it through the floor into the crawl space below. I could place this fan on a timer so that it goes on sporadically throughout the day and night to "push" some additional living space heat into the crawl space. I don't think that this loss of room heat would be a waste as the floor would benefit from the heat in the crawl space.Any thoughts, ideas, or additional comments are appreciated.