Why Is My Hot Tub Not Heating in Winter? Central Alberta winters are no joke, and a cold hot tub is more than just an inconvenience. If your hot tub is not heating in winter, it is usually a sign that something is restricting water flow, affecting your heater, or allowing heat to escape faster than it should. Before jumping into deeper issues, here are a few quick things to check first. Quick Things to Check First If your water is cold, start here: Check if your breaker has tripped Make sure...