Planning to close down the house for the winter months

Q: My father has a 30 year-old, nailed down hardwood floor. This winter is the first time he is planning to close down the house for the winter months (drain water pipes and shut down the heat). He is concerned that if he does not leave any heat on in the house that his hardwood floors will be damaged.

The outdoor temperatures can vary from highs of 9 to 12C during the day to lows of -30C at night. The house would be closed between January and April probably. Is my father right to be concerned about his hardwood floors? If yes, what minimum temperature should he keep in the house?

A: I’m not as concerned with the cold temperatures per se as I am with the lack of any exchange of fresh air in the house. I would be worried about possible condensation eventually occurring throughout the house. Perhaps he could leave the heat set for around 40F-50F to keep things above freezing. Draining the pipes is still a good idea just in case something went wrong with the furnace.

It would be interesting to monitor the RH in the house under real world conditions, both when it is very cold inside and when it is above freezing. One thing I am sure of: Unless the house has a lot of windows exposed to direct sunlight, if it gets freezing cold in the house, it will stay freezing cold.