Prepping Your Tankless Water Heater for Winter (Demo)

tankless water heating in winter

Things around the house have a nasty habit of freezing during the winter. Unless you decide to move to a warm, southern climate, you’d better take the steps to break that habit. Especially with the icy start to this winter season, one of the last things you want those frigid temperatures to affect is your Noritz tankless water heater.

Although designed to withstand winter’s worst, tankless water heating systems should not be completely neglected during the cold weather, especially when it comes to their external plumbing. Here are some simple tips on ensuring your water remains warm this winter.

Insulate your external pipes:  Although the tankless unit itself contains freeze prevention heaters, the hot- and cold-water plumbing lines leading to and from the heater need protection as well. If freezing does happen, this is where it will occur. Protect these pipes by insulating them with something as simple as aluminum foil. More reliable options include heat tape, electric heaters, solenoids and/or pipe covers.


Make sure you have enough gas: If the gas appliances in your home require more gas than your meter is sized to handle, you run the risk of an insufficient fuel supply, which can hinder performance. Add all gas-appliance Btuh demands and compare to gas meter size. If the meter capacity is less than your total household Btuh load, contact your gas company.


Keep the water flowing: Water flowing through your pipes will lessen the chance of freezing. If you have a recirculation plumbing system, keep it running frequently during the winter. Although this will cost more in energy, it’s preferable to your pipes freezing and a lack of warm water. If you don’t have a recirculation system, let a hot-water faucet slightly trickle (.1 gal./minute) to prevent freezing on extremely cold days.


Stay powered: Your tankless water heater’s freeze prevention heaters need electrical power to operate. Never unplug the power or disconnect electrical flow to the unit during the winter. In fact, consider acquiring a backup generator just in case the power happens to go out.


Consider your venting: In extremely cold temperatures, back draft entering through your unit’s vents might be an issue. To mitigate a back draft’s effects, run your vent vertically instead of horizontally.


Keep your unit in a warm area: If you live in an area with subzero weather conditions, install your tankless unit in a heated part of your home. At the very least, make sure your unit is installed on the walls adjacent to a heated space rather than to the outdoors.

All of these tips are especially relevant if you live in a colder climate. But, as we have seen this season, even warmer climates are at risk for freezing temperatures from time to time. If you properly prepare your tankless water heater, though, you’ll have nothing to worry about.

For more specific freeze-prevention tips regarding your particular Noritz tankless water heater, please find your owner’s manual at

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