How To Keep Tankless Water Heater From Freezing?

To prevent tankless water heaters from freezing, properly insulate the unit and the piping. By insulating the tankless water heater and the pipes, you can keep the water flowing and prevent freezing during cold temperatures.

This ensures that your tankless water heater operates efficiently and avoids any potential damage that freezing can cause. Additionally, it is important to keep the heater in a warm and enclosed space, away from extreme cold temperatures. By following these steps, you can effectively protect your tankless water heater from freezing and maintain its optimal performance.

How To Keep Tankless Water Heater From Freezing?


Why Tankless Water Heaters Are Prone To Freezing

Tankless water heaters are a popular choice for homeowners due to their energy efficiency and unlimited hot water supply. However, they do come with a drawback – they are more prone to freezing compared to traditional tank water heaters. Understanding the reasons behind this vulnerability is crucial in preventing freezing and potential damage to your unit.

Let’s take a closer look at some key factors that contribute to the freezing of tankless water heaters.

Lack Of Water Circulation In Standby Mode

  • When a tankless water heater is not in use, it enters standby mode, waiting for a demand for hot water. During this period, water circulation may be limited or even stagnant, making it more vulnerable to freezing.
  • Lack of water movement allows low temperatures to affect the unit’s internal components, including the heat exchanger and water pipes.
  • The absence of regular water flow increases the likelihood of freezing, especially in colder regions or during frigid winter months.

Exposure To Cold Outdoor Temperatures

  • Unlike traditional tank water heaters that are usually stored indoors, tankless water heaters are often installed in exterior locations or unheated areas.
  • Exposure to cold outdoor temperatures can significantly increase the potential for freezing. The lack of insulation and direct contact with icy air can cause the unit’s components to freeze up.
  • Even if your tankless water heater is installed indoors, if it is in a cold basement or attic space with inadequate insulation, it can still be susceptible to freezing.

Inadequate Insulation

  • Insulation plays a crucial role in protecting tankless water heaters from freezing.
  • Proper insulation not only helps maintain a suitable temperature for the unit but also prevents the infiltration of cold air.
  • If your tankless water heater is not adequately insulated, heat loss may occur, making it less efficient and more prone to freezing.
  • Additionally, lack of insulation in the water pipes connected to the unit can cause them to freeze, leading to potential damage.

Understanding why tankless water heaters are prone to freezing is essential for taking preventive measures. By ensuring adequate water circulation during standby mode, protecting the unit from exposure to cold outdoor temperatures, and improving insulation, you can minimize the risk of freezing and keep your tankless water heater working optimally.

Stay tuned for our upcoming tips on how to prevent tankless water heaters from freezing.

The Importance Of Preventing Freezing In Tankless Water Heaters

Freezing temperatures can wreak havoc on tankless water heaters, causing them to malfunction or even break down completely. It is crucial to take preventive measures to avoid costly repairs and replacements, ensure uninterrupted hot water supply, and increase the lifespan of the water heater.

Avoid Costly Repairs And Replacements:

  • Insulate the pipes: Properly insulating the pipes connected to your tankless water heater can prevent freezing. Use foam insulation sleeves or heat tape to protect the pipes from extreme temperatures.
  • Install a freeze protection system: Consider installing a freeze protection system that automatically turns on when temperatures drop. These systems use internal heaters to keep the water heater components warm and prevent freezing.
  • Drain the water heater: If you anticipate freezing temperatures and won’t be using hot water for an extended period, drain the tankless water heater to avoid any stagnant water freezing inside.
  • Check for leaks: Regularly inspect your tankless water heater for any leaks or cracks that may allow cold air to enter. Repairing these issues early on can prevent freezing.

Ensure Uninterrupted Hot Water Supply:

  • Maintain a constant flow: To minimize the risk of freezing, keep a slow trickle of hot water flowing from a faucet connected to the tankless water heater. This continuous flow helps prevent the water inside from freezing.
  • Keep the surrounding area warm: Ensure the area around the water heater is adequately insulated and free from drafts. This helps maintain the ambient temperature and prevents freezing.
  • Consider an external enclosure: If your tankless water heater is located in an area prone to freezing, investing in an external enclosure can provide added protection against freezing temperatures.

Increase The Lifespan Of The Water Heater:

  • Schedule regular maintenance: Routine maintenance and inspections by a professional can help identify and resolve potential issues before they escalate. This can extend the lifespan of your tankless water heater.
  • Flush the system annually: Flushing out sediment and mineral buildup from the tankless water heater once a year can help maintain its efficiency and reduce the risk of freezing.
  • Avoid extremely low temperatures: If possible, avoid exposing your tankless water heater to extremely low temperatures. Locate it in a conditioned space or take appropriate measures to protect it during freezing weather.

Preventing freezing in tankless water heaters is essential for their longevity and consistent hot water supply. By following these preventive measures, you can minimize the risk of costly repairs, ensure uninterrupted hot water, and increase the lifespan of your water heater.

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Stay ahead of freezing temperatures and take proactive steps to protect your tankless water heater investment.

Insulating The Water Pipes

One of the key ways to keep your tankless water heater from freezing is by insulating the water pipes. Insulation can help prevent heat loss and protect your pipes from freezing temperatures. Here are a few effective methods to insulate your water pipes and ensure they stay safe:

  • Wrapping pipes with insulation sleeves: Insulation sleeves are an easy and affordable way to protect your water pipes. These sleeves are made of foam or rubber and can be easily installed by sliding them over the pipes. They provide a barrier that helps to retain heat and prevent freezing.
  • Using heat tape or cable for added protection: Heat tape or cable is another excellent option for preventing freezing. This self-regulating electrical tape can be wrapped around the pipes and plugged into an electrical outlet. The tape generates heat to keep the pipes warm and prevent freezing during cold weather.
  • Sealing gaps and cracks in the walls or floors around the pipes: In addition to insulating the pipes themselves, it’s important to inspect and seal any gaps or cracks in the walls or floors around the pipes. This will help to prevent cold air from seeping in and affecting the temperature of the pipes. Use caulk or weatherstripping to seal these gaps and ensure maximum insulation.

Remember, it’s crucial to follow the manufacturer’s instructions and guidelines when insulating your water pipes. Additionally, consider consulting a professional if you’re unsure about the process or have specific requirements. Proper insulation will not only help prevent freezing but also improve the overall efficiency and performance of your tankless water heater.

Insulating The Water Heater Unit

Keeping your tankless water heater from freezing is crucial to avoid costly damage and ensure uninterrupted hot water supply, especially during the colder months. One effective way to achieve this is by insulating the water heater unit. There are several methods you can use to insulate your tankless water heater and protect it from freezing temperatures.

Here are the key points to consider:

  • Adding an insulation blanket to the unit:
  • An insulation blanket is a simple and cost-effective solution for preventing your tankless water heater from freezing.
  • It helps to retain heat and maintain the desired temperature, even in colder conditions.
  • Make sure to choose an insulation blanket that is specifically designed for tankless water heaters.
  • Follow the manufacturer’s instructions carefully when installing the insulation blanket to ensure proper coverage and avoid any safety hazards.
  • Installing a freeze protection kit:
  • A freeze protection kit is an ideal option for areas with extremely cold temperatures.
  • It includes features such as electric heating elements and temperature sensors that prevent freezing.
  • Consult a professional plumber or the manufacturer’s guidelines for the proper installation of the freeze protection kit.
  • Regularly inspect the kit to ensure it is functioning correctly and replace any faulty components.
  • Placing a thermal cover over the unit during colder months:
  • A thermal cover or insulated enclosure provides an additional layer of protection against freezing temperatures.
  • It helps to keep the surrounding air warm and shields the water heater unit from the cold.
  • Choose a cover that is designed specifically for tankless water heaters and ensure it fits securely.
  • Remember to remove the cover during warmer months to prevent overheating and allow proper ventilation.

Remember, insulating your tankless water heater is a proactive measure that can save you from the hassle and expense of dealing with frozen pipes and a malfunctioning water heater. By following these steps and taking the necessary precautions, you can ensure a reliable and efficient hot water supply throughout the year.

Maintaining A Steady Water Flow

When it comes to keeping your tankless water heater from freezing, one of the most important aspects is maintaining a steady water flow. In colder weather, it’s crucial to take extra precautions to prevent any potential freezing issues. Here are some key points to consider:

  • Running hot water periodically during colder weather: Running hot water through your tankless water heater at regular intervals can help prevent freezing. The flowing water helps keep the internal components warm and prevents any ice formation. Aim to do this at least once every few hours during extremely cold temperatures.
  • Adjusting the temperature to prevent overheating: Maintaining the right temperature setting on your tankless water heater is essential. While you don’t want your water to freeze, you also don’t want to risk overheating the unit. It’s recommended to keep the temperature setting above 40 degrees fahrenheit to prevent freezing without risking excessive heat.
  • Checking for any blockages or restrictions in the water line: Regularly inspect your tankless water heater’s water line for any blockages or restrictions. Even a minor obstruction can disrupt the water flow and increase the chances of freezing. Pay close attention to ensure there are no kinks, leaks, or debris hindering the smooth flow of water.
  • Ensuring proper insulation: Properly insulating your tankless water heater and its pipes helps maintain a steady water flow and prevents freezing. Insulate both the unit itself and the exposed pipes using insulation sleeves or wraps. This extra layer of insulation acts as a barrier against the cold temperatures.
  • Regular maintenance and cleaning: Keeping your tankless water heater well-maintained and clean is essential for optimal performance and preventing freezing issues. Follow the manufacturer’s maintenance guidelines, which typically include descaling and flushing the unit to remove any mineral buildup or debris that can obstruct the water flow.
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Remember, maintaining a steady water flow is crucial in preventing freezing and ensuring the longevity of your tankless water heater. By following these key points and taking necessary precautions, you can keep your unit safe even during colder weather conditions.

Promoting Water Circulation

Installing A Recirculation System

  • A recirculation system can help promote water circulation in your tankless water heater, preventing freezing and ensuring constant hot water supply.
  • Here are key points to know about installing a recirculation system:
  • Recirculation pumps are typically installed near the water heater, creating a loop that maintains a constant flow of warm water through the pipes.
  • This constant circulation keeps the water temperature above freezing and eliminates the risk of freezing pipes.
  • By installing a recirculation system, you can enjoy instant hot water at any faucet in your home without waiting for it to heat up.

Adjusting The Settings To Encourage Continuous Water Flow

  • Adjusting the settings of your tankless water heater can be another effective way to encourage continuous water flow and prevent freezing.
  • Consider these key points when adjusting the settings:
  • Check the temperature settings on your water heater. It’s advisable to set it at a slightly higher temperature to maintain a consistent flow of hot water.
  • Increase the flow rate to ensure that water moves through the pipes more quickly, reducing the chances of freezing.
  • Some tankless water heaters have freeze protection settings, so make sure to enable this feature to prevent freezing during colder temperatures.
  • Regularly check and maintain the water heater to ensure it is functioning correctly and the settings are adjusted accordingly.

Using A Hot Water Demand System To Reduce Standby Time

  • A hot water demand system can significantly reduce the standby time between hot water usages, making it an effective solution to prevent freezing in tankless water heaters.
  • Take note of these points when using a hot water demand system:
  • This system uses a pump and sensor to detect when hot water is needed, instantly delivering hot water to the desired faucet or appliance.
  • By reducing the standby time, the chances of freezing are minimized, as the water is constantly flowing through the pipes.
  • The hot water demand system provides convenience and energy efficiency, ensuring hot water is available when needed while reducing water waste.
  • Consult a professional plumber to install the hot water demand system correctly and ensure it integrates seamlessly with your tankless water heater.

Remember, promoting water circulation is crucial in preventing freezing in tankless water heaters. Installing a recirculation system, adjusting the settings for continuous water flow, and utilizing a hot water demand system are effective ways to maintain a steady supply of hot water and avoid freezing issues.

Draining And Winterizing The System

Tankless water heaters are a great investment, providing hot water on-demand and taking up less space compared to traditional water heaters. However, during cold winter months, the risk of freezing can cause damage to the water heater and the surrounding pipes.

To prevent this from happening, it is essential to properly drain and winterize the system. Here are some key steps to follow:

Draining The Water Heater And Pipes During Extended Periods Of Non-Use:

  • Before draining the system, ensure that the power and gas supply to the water heater are turned off. This will prevent any accidents or damage while working on the unit.
  • Locate the main water shut-off valve and turn it off to stop the flow of water into the system.
  • Open all the hot water taps in your home to relieve the pressure inside the pipes and water heater.
  • Next, find the drain valve on the water heater and attach a hose to it. Place the other end of the hose in a suitable drainage area, such as a floor drain or outside.
  • Open the drain valve and let all the water flow out of the water heater and pipes. Be patient as this may take some time, depending on the size of your system.
  • Once the water has completely drained from the water heater, close the drain valve and remove the hose.
  • Finally, close all the hot water taps in your home and make sure they are tightly sealed to prevent any air from entering the system.

Adding Antifreeze To The System For Extra Protection:

  • To provide an additional layer of protection against freezing, you can add antifreeze to the system.
  • Choose a non-toxic antifreeze specifically designed for plumbing systems, as regular automotive antifreeze can be harmful if ingested.
  • Begin by turning off the water supply to the tankless water heater.
  • Use a funnel to pour the appropriate amount of antifreeze into the cold water inlet of the water heater. Refer to the manufacturer’s instructions or consult a professional plumber for the recommended quantity.
  • Turn on a hot water tap in your home to allow the antifreeze mixture to circulate throughout the system.
  • Once the antifreeze has run through the system, turn off the hot water tap and close the water supply valve.
  • It’s important to note that if you have a recirculation system, you may need to add antifreeze to that as well. Consult the system’s manual or seek professional guidance for specific instructions.

Remember, proper draining and winterizing of your tankless water heater system is crucial to prevent freezing and potential damage. By following these steps, you can ensure that your water heater stays in good working condition throughout the winter season. Stay warm and enjoy a continuous supply of hot water!

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Monitoring And Regular Maintenance

Regular monitoring and maintenance are essential to ensure your tankless water heater functions optimally and remains protected from freezing. By regularly checking for leaks or signs of freezing, flushing the system annually, and seeking professional inspection and servicing, you can prevent freezing and extend the lifespan of your water heater.

Here are key points to consider when maintaining and monitoring your tankless water heater:

  • Checking for leaks or signs of freezing regularly:
  • Inspect the area around your tankless water heater for any signs of leaks or water accumulation.
  • Check the pipes, valves, and connections for any visible leaks or potential issues.
  • Look for frost or ice formation on the exterior of the heater, which may indicate freezing.
  • Flushing the system annually to remove sediment buildup:
  • Sediment buildup can affect the efficiency of your tankless water heater and increase the risk of freezing.
  • Follow the manufacturer’s instructions to safely flush the system and remove any accumulated sediment.
  • Flushing the system annually helps maintain the heater’s performance and prevents clogs.
  • Seeking professional inspection and servicing:
  • Consider scheduling an annual inspection by a qualified professional to assess your tankless water heater.
  • Professional servicing can identify potential issues, such as damaged components or inadequate insulation.
  • They can advise you on necessary repairs or upgrades to better protect your water heater from freezing.

Remember, monitoring and regular maintenance play a vital role in preventing freezing, improving efficiency, and prolonging the lifespan of your tankless water heater. By staying proactive and following these steps, you can ensure a reliable supply of hot water and peace of mind throughout the colder months.

Keeping Your Tankless Water Heater Safe From Freezing

Freezing temperatures can pose a significant risk to your tankless water heater, potentially causing damage and costly repairs. However, by implementing insulation and preventive measures, ensuring proper water flow and circulation, and regular maintenance and monitoring, you can keep your tankless water heater safe from freezing.

Implementing Insulation And Preventive Measures

To protect your tankless water heater from freezing temperatures, consider the following insulation and preventive measures:

  • Insulate the pipes: Insulating the pipes connected to your tankless water heater can help prevent freezing. Use foam insulation sleeves or tape to wrap the exposed pipes.
  • Insulate the unit: Insulating the tankless water heater itself is also crucial. Check the manufacturer’s guidelines for approved insulation materials and methods, as improper insulation may void the warranty.
  • Seal air gaps: Identify any air gaps or leaks around the unit and seal them properly. This will prevent cold air infiltration and keep the surrounding area warmer.
  • Install a freeze protection valve: A freeze protection valve can automatically release water from the pipes when the temperature drops, preventing freezing and potential damage.
  • Maintain a safe temperature: Set your tankless water heater to a safe temperature, even when you’re away from home. A slightly warmer setting can help prevent freezing during periods of extreme cold.

Ensuring Proper Water Flow And Circulation

Proper water flow and circulation are crucial in preventing freezing. Consider the following steps to ensure your tankless water heater operates efficiently in colder temperatures:

  • Use hot water regularly: Regularly using hot water helps maintain a consistent flow and prevents stagnation, reducing the risk of freezing.
  • Check for obstructions: Examine the pipes and fittings for any obstructions or blockages that may hinder water flow. Remove any debris or sediment that could impede proper circulation.
  • Run water during freezing temperatures: During extremely cold weather, it’s advisable to let a small stream of hot water run through one of your faucets. This constant flow can prevent the water from freezing within the pipes and the tankless water heater.

Regular Maintenance And Monitoring For Potential Issues

Regular maintenance and monitoring are essential in ensuring your tankless water heater remains protected from freezing. Consider the following practices:

  • Schedule professional inspections: Arrange annual inspections by a qualified technician who can identify any potential issues before they become major problems.
  • Keep the area clear: Ensure the space surrounding your tankless water heater is clear of clutter and debris, allowing for proper air circulation and preventing overheating.
  • Check for leaks: Regularly inspect the unit and its connections for any signs of leaks. Addressing leaks promptly can prevent water damage and freezing during colder temperatures.
  • Monitor the thermostat: Regularly monitor the thermostat and make sure it’s functioning correctly. Any unusual behavior or inconsistent readings should be investigated promptly.

By implementing insulation and preventive measures, ensuring proper water flow and circulation, and regularly maintaining and monitoring your tankless water heater, you can effectively protect it from freezing temperatures. These practices will not only ensure uninterrupted hot water supply but also help prevent potential damage and costly repairs.


Protecting your tankless water heater from freezing is essential for ensuring its optimal performance and longevity. By following the tips and precautions mentioned in this blog post, you can effectively prevent freezing issues and avoid costly repairs or replacements. Remember to insulate the pipes, use heat tape, and maintain a consistent power supply to keep the water flowing smoothly.

Additionally, regular maintenance and occasional flushing of the unit will help remove debris and prevent clogs. By being proactive and taking preventive measures, you can enjoy the benefits of a tankless water heater without worrying about freezing temperatures affecting its functionality.

Stay warm and worry-free with these simple yet effective strategies for protecting your tankless water heater during winter months.


I am a mechanical engineer and love doing research on different home and outdoor heating options. When I am not working, I love spending time with my family and friends. I also enjoy blogging about my findings and helping others to find the best heating options for their needs.