he area where freezing occurs is toward the edge of the house. A smal l electric space heater aimed at the area seems to get them dethawed within 24 hours. The second time was
kitchen, so I aimed a space heater into the bottom kitchen cabinet and with in a day water was flowing again.
r lines should never be run through exterior walls or an attic.
Water lines are run through exterior walls here in NJ in most houses. It frequently gets in the single digits a few times a winter. I've never had the pipes freeze. I have both the kitchen and master bath sinks routed through outside walls on opposite ends of the house. It was below 32F for two weeks, in the single digits many times, the coldest night was -2F. No freezing. A big part of it is if the insulation is put in properly, the pipes on the warm side and that there are no holes where wind can blow in and that the house is heated to a reasonable temperature. For sure routing the pipes without using an outside wall eliminates the chance, but just saying there are a lot of houses with pipes in outside walls in places that get pretty cold without problems.
If I'm leaving the house set way back for a trip, etc, then I leave the cabinet doors open under the sinks so that more warmth gets in.