Did you know that hot water freezes faster than cold? A tenant called today to say that her hot water wasn’t working in a few sinks and that neither hot nor cold water were working in one sink. At first I thought it might be a failed hot water heater, except that the non-functioning cold water didn’t make sense. I called a plumber who told me that hot water pipes freeze faster than cold ones because there is more air in hot water. Here is the longer explanation: https://medium.com/the-physics-arxiv-blog/why-hot-water-freezes-faster-than-cold-physicists-solve-the-mpemba-effect-d8a2f611e853. My solution to this problem may be to install an electric wall heater to the left of the plumbing above this door to keep the area warm.