How to Install a Navien Tankless Water Heater?

  • Installing a tankless water heater is a simple process that needs to be thoroughly understood. We’ll explore this step-by-step guide on installing a Navien tankless water heater to make the process seamless.
  • We’ll also examine the safety measures you must consider before embarking on this installation journey.

Tankless water heaters have gained tremendous popularity in recent years due to their energy efficiency, space-saving design, and the luxury of having an endless hot water supply on demand. If you’re tired of running out of hot water or dealing with bulky traditional water heaters, it’s time to consider upgrading to a Navien tankless water heater.

Navien is a leading brand in the industry, renowned for its innovative technology and commitment to providing reliable and high-performing tankless water heaters. Installing a Navien tankless water heater in your home allows you to experience the convenience and comfort of never-ending hot water while reducing energy consumption and utility bills.

This guide will walk you through the step-by-step process of installing a Navien tankless water heater in your home. From preparing for installation to connecting the necessary lines and ensuring safety, we’ll cover everything you need to know to complete the installation successfully.

Understanding Navien Tankless Water Heaters

Before diving into the installation process, it’s crucial to understand how Navien tankless water heaters work and the advantages they offer over traditional tank-based water heaters. Unlike conventional models that store and continuously heat a large volume of water, tankless water heaters heat water on demand as it passes through the unit. This approach eliminates the need for a storage tank and provides hot water instantaneously whenever needed. Navien tankless water heaters utilize advanced technology to deliver precise temperature control, energy efficiency, and an uninterrupted hot water supply.

Preparing for Installation

To ensure a smooth installation process, take a few essential steps beforehand. Gather the necessary tools and materials, including pipe wrenches, adjustable wrenches, pipe cutters, gas tape, a screwdriver, and a drill. Familiarize yourself with the electrical and plumbing requirements outlined in the Navien tankless water heater’s installation manual.

It’s crucial to have the appropriate electrical and gas connections in place before beginning the installation. Additionally, choose a suitable location for your Navien tankless water heater that allows for proper venting and access for maintenance.

For safety reasons, turn off the gas and electricity supply to your home before starting the installation. Once you have completed these preparations, you can begin installing your Navien tankless water heater.

Steps for Installing a Navien Tankless Water Heater

Shut off the water supply

Before beginning the installation process, shutting off the main water supply to your home is crucial. Locate the main water valve and turn it off to prevent any water from flowing into the system while you work. This step ensures a safer and more efficient installation.

Disconnect the old water heater

If replacing an existing water heater with a Navien tankless unit, you must first disconnect the old one. Begin by turning off the power supply to the old heater and shutting off the gas line or disconnecting the electrical connections. Drain any remaining water from the old unit by opening the drain valve and allowing the water to flow out. Once the old heater is disconnected and drained, it can be safely removed.

Mount the Navien tankless water heater

With the old water heater removed, it’s time to mount your new Navien tankless water heater. Follow the manufacturer’s instructions carefully to ensure proper installation. Choose a suitable location that allows easy access for future maintenance and meets the clearance requirements specified in the installation manual. The unit should be mounted securely and level to ensure its stable operation.

Connect the water and gas lines

Connect the water lines to the Navien tankless water heater. Use appropriate fittings and ensure tight connections to prevent leaks. It’s essential to follow the manufacturer’s instructions regarding the type and size of pipes for the water lines. Connect the gas line to the unit if your model requires it. Use gas tape or pipe joint compound to seal the threaded connections, ensuring a secure and leak-free connection.

Vent the exhaust gasses

Navien tankless water heaters produce exhaust gasses during operation, which need to be safely vented outdoors. Install the venting system according to the manufacturer’s specifications and local building codes. Pay attention to the venting requirements, such as the type of vent pipe, maximum vent length, and proper slope for condensate drainage. Proper venting is essential for the safe and efficient operation of the unit.

Install a condensate drain line

Navien tankless water heaters generate condensation during operation, especially in high-efficiency mode. Installing a condensate drain line is important to remove the condensate from the unit safely. Follow the manufacturer’s instructions to route the drain line properly, ensuring it has the necessary slope and terminates at an appropriate drainage point.

Connect the power supply

Depending on the model of your Navien tankless water heater, it may require an electrical connection. Refer to the installation manual for specific electrical requirements and instructions. If you’re not experienced with electrical work, it’s best to consult a licensed electrician to ensure a safe and compliant installation. Connect the unit to the appropriate power source, following all local electrical codes and regulations.

Test for water and gas leaks

Once the installation is complete, testing the system for any gas or water leaks is crucial. Start by checking all gas connections using a gas leak detection solution. Apply the solution to all joints and connections and observe for any bubbles which indicate a gas leak. If you detect a leak, immediately shut off the gas supply and consult a professional. Similarly, inspect all water connections and fittings for any signs of leaks. Tighten any loose connections and address any leaks before proceeding.

Turn on the water supply

With the installation complete and no leaks detected, it’s time to turn on the main water supply. Slowly open the valve and allow the water to flow into the system.

Safety Considerations

Safety should be a top priority when installing a Navien tankless water heater. Follow these important safety considerations to ensure a secure and problem-free installation:

Follow manufacturer instructions

Carefully read and follow the installation manual provided by Navien. It contains detailed instructions specific to your tankless water heater model.

Handle gas lines and electrical connections safely

If you’re not experienced with gas or electrical work, hiring a professional technician to handle these aspects of the installation is recommended. Gas leaks and faulty electrical connections can be dangerous.

Test for gas and water leaks

After completing the installation, thoroughly inspect all gas and water connections for leaks. Apply a gas leak detection solution to joints and connections to ensure no leaks. Check for water leaks around connections and fittings.


Installing a Navien tankless water heater is a great way to upgrade your home’s water heating system and enjoy the benefits of energy efficiency and endless hot water. By following the step-by-step installation guide provided in this article and adhering to the safety considerations, you can successfully install a Navien tankless water heater and experience its exceptional performance. Consider the installation manual for model-specific instructions, and seek professional assistance if you’re unsure about handling gas or electrical connections.

Frequently Asked Questions

How long does it take to install a Navien tankless water heater?

The installation time can vary depending on factors such as the complexity of the installation, existing infrastructure, and the installer’s experience. On average, a professional installation can be completed in a few hours.

Can I install a Navien tankless water heater myself?

While it’s possible for skilled homeowners to install a Navien tankless water heater, hiring a professional plumber or technician is recommended to ensure proper installation and compliance with local building codes.

Are Navien tankless water heaters more energy-efficient than traditional tank-type water heaters?

Yes, Navien tankless water heaters are highly energy-efficient compared to traditional tank-based water heaters. Since they only heat water on demand, they eliminate standby energy losses associated with storing hot water in a tank.

How long do Navien tankless water heaters last?

Navien tankless water heaters can last 20 years or more with proper maintenance. Regular maintenance, such as flushing the unit and inspecting/cleaning the intake air filter, is essential to prolong its lifespan.

Can Navien tankless water heaters supply hot water to multiple outlets simultaneously?

Yes, Navien tankless water heaters are designed to simultaneously provide hot water to multiple outlets. To ensure optimal performance, the unit’s capacity should be selected based on your household’s hot water demands.


Do you think Navien manufactures some of the best tankless water heaters?

  • Yes
  • No
  • Maybe