OK- For the ones who have experienced the flood disaster-the time it took to fix everything-THEN replace the unit........well, forget about the time again.........here is your CHEAP insurance against your ON DEMAND WATER HEATER from freezing and leaking !! These super quality ceramic mini-heaters will save your bacon !! High winds or a negative pressure [caused by a bath fan or range hood or wood stove or [you get the picture]] in the house can cause cold air to infiltrate thru the water heater. What temp does water freeze? The stainless steel clips hold the heaters on to the piping that goes around the heat exchange coil. Does it run all the time ? NO !! It has a thermostat that turns the heaters on ONLY when the temp gets dangerously close to freezing. No waste here! Operates on 110 volts ac. NEW !! Postage is $5 . Paypal is OK. Thanks for looking !! 320-8224 Location: Alaska it's NOT ok to contact this poster with services or other commercial interests alaska