One consideration is the ice maker line in our 38gk and the shower controls both froze and burst in Texas when it got down in the teens for a couple of days.
in that particular unit the ice maker line ran from under the sink OUT the bottom and was exposed under the slide. Fixed it by draining and turning off ice maker from then on
There also must have been a lot of air infiltration in the shower area as we always noticed cold air coming out the pocket door next to it.