A tankless water heater performs well in winter months but even it has some limitations. Tankless water heaters make use of a condenser that pre-warms the water, so it does not take you very long time to reach the pre-set temperatures for using. Approximately, the water reaches the temperature set by the home owners at the rate of 1.6 gallons per minute . In the beginning it may flow with less pressure, so that the water heater has time to heat the water, but it is as hot as desired when it gets to its destination. Contrary to common belief, the hot water temperatures produced by the tankless water heater are not restricted by the temperatures outside. However, the tankless hot water heater can freeze if certain precautions are not taken when the temperatures drop below a certain level.

The majority of indoor and outdoor tankless water heaters have built-in freeze protection against short-term winter temperatures ranging from -7 degrees Fahrenheit to -21 degrees Fahrenheit. This protection cannot resist long term below freezing temperatures. To avoid your tankless water heater from freezing in the winter there are several steps you should take. To begin winterizing your tankless water heater you should take the follow steps:

1. First turn the unit off and unplug its power source.

2. Next, turn off the water supply and drain the water from the water heater.

3. Minimize the water pressure and disconnect the water pipes from the water heater.

4. Place a cover over the vent termination for intake and exhaust to hold debris out.

5. After that, when setting up a concentric or dual vent system face vent pipes away from the wind to prevent freezing.

6. Set up drain pipes in areas not subject to freezing such as inside a wall.

7. Enable ample combustion air for gas powered appliances to prevent negative draft from freezing the water in a tankless unit or use a backdraft reducer which closes the backdraft flapper.
These procedures can protect your water heater through the entire winter withstanding freezing temperatures in your local area. We of course recommend that call an expert to winterize your tankless water heater in you house. Especially if it expected that the current weather will remain cold for an extended period of time of this winter.