Winter Prep 101: Protect Your Tankless Water Heater During a Freeze

South Louisiana winters are usually mild, but occasionally we experience a hard freeze that has the potential to cause serious damage to outdoor tankless water heaters if they are not properly protected.

The good news is that a little preparation goes a long way in preventing costly repairs and unexpected loss of hot water.

✅ What is Built In Freeze Protection?

Most outdoor tankless water heaters include internal freeze protection. While this feature is helpful, it does have important limitations homeowners should understand.

Built in freeze protection:

• Only works if the unit has power
• Protects internal components only
• Does not protect exposed exterior piping
• May not prevent damage during extended freezes or power outages

Think of freeze protection as a safety net, not a winter coat.

🧤 How to Protect Your Tankless Water Heater During a Freeze

When temperatures approach freezing, following these steps in order of importance can help protect your system.

🔑 Key Step: Let Water Drip

When freezing temperatures are expected:

• Run a small, steady drip of both hot and cold water
• Use the fixture farthest from the water meter

This keeps water moving through the entire plumbing system and through the tankless heater.

This is the single most effective way to prevent freeze damage.
Do not drain the system. Draining often leaves water trapped inside the heater, and when that water freezes it can cause serious internal damage.

✔ Keep Power On

• Do not turn off electrical power to the tankless unit during cold weather
• Internal freeze protection systems require power to function

✔ Insulate Exposed Pipes

Wrap any visible or exposed water lines with:

• Foam pipe insulation
• Insulating tape, especially around fittings and valves

✔ Use an Approved Cover if Needed

If temperatures are expected to stay below freezing for an extended period:

• Install a manufacturer approved tankless water heater cover
• Do not use plastic bags, tarps, or improvised wraps, as these can trap moisture and cause damage

🚨 Signs of Freeze Damage to Watch For

After a freeze event, contact a professional if you notice any of the following:

• No hot water
• Error codes displayed on the unit
• Water leaking around the heater or piping
• Reduced water pressure

Taking a few proactive steps before a freeze can help protect your outdoor tankless water heater and keep your home comfortable all winter long.