When It's Cold Outside, Will My Outdoor Tankless Hot Water Heater Still Work? - McLay Services, Inc.
Your water heater isn’t the only thing water runs through. Your pipes are also at risk of freezing, and they don’t have the freeze prevention mechanisms that most tankless water heaters have.
If you’re unfamiliar with pipe insulation, here are a few materials you can use to protect your pipes from freeze damage effectively:
Heat tape insulation
Polyethylene insulation
Fiberglass insulation