Customer stated that they had no hot water whatsoever. At one point today the kitchen started to get hot but it would take a while to get there. Master bathroom had nothing when any of the hot faucets were opened. Upon arrival opened up hot faucet in master bathroom sink and found water trickling out then it went to full pressure. When coming out, hot water in master bathroom sink was ice cold then got real hot real fast. Tested shower in master, and the same thing. Explained that it was possible the master may have froze but since thawed out. Spoke to customer about insulation and they will see if it happens again.