Rinnai Vs Navien: The Ultimate Guide

Tankless water heaters have quickly become a great alternative to regular water heaters for several reasons: They are energy efficient, safer and can provide an unlimited source of hot water for all of your home’s needs.

Rinnai and Navien are amongst the most popular tankless water heater systems on the market. Both brands offer a variety of systems that have been proven to work in various environments. But there are certainly differences between them.

In this post, I will discuss which system I believe is better having installed both systems and evaluated their performance over time.

Navien washington engergy
Navien Tankless System Image Credit: Washington Energy Services

Navien or Rinnai: Which has the better Tankless Unit Brand?

Navien and Rinnai were both founded in Japan. Japan is a country known for it technological capabilities, bringing us several products we use in the United States from automobiles to computers and much more.

Navien was founded in 1978 but has been serving the water heater market in the United States since 2006. Rinnai however has a much longer history than Navien. The company was founded in 1920 and began selling water heaters in the US in 1974.

Rinnai, is a more recognizable name due to its longer presence in homes in the United States. Also, its product line extend well beyond water heaters and boilers to furnaces and radiant heating systems.

Navien has traditionally been more focused on water heating systems though they are beginning to expand their reach.

Both brands are well established in the United States at this point in their histories. But because of its longer history and breath of products, Rinnai has a slight edge over Navien when it comes to brand recognition.

Navien vs Rinnai: Which is More Energy Efficient?

Most modern appliances in home come with an Energy Star Rating. This rating incorporates what is called the Universal Energy Factor (UEF) into the rating system. The higher the UEF, the more efficient the appliance is.

All of Navien and Rinnai water heaters models are energy star compliant. Specifically, Rinnai’s UEF rating for its models range from 0.85 to 0.93. Navien’s UEF ranges up to 0.96

In general these efficiencies are very comparable and will make only a minor difference in your energy consumption based on your hot water usage. Navien achieves slightly higher efficiency ranges. But its brands may deliver less overall heating capability (about 150,000 BTU compared to 199,000 BTU for Rinnai)

Navien has the slight edge here on energy efficiency which translates to more savings over the long term on electricity usage.

Rinnai tankless water heater

Are Navien or Rinnai Tankless Water Heaters more Expensive to buy and Operate?

There are two primary factors that determine the cost of your hot water heater Installation: Unit Price and Installation Cost.

Water Heater Price

Navien and Rinnai have both carried several models of tankless systems which can make it quite a task to determine which brand offers the best value for your money.

In general for both brands, you will pay between $600 and $2,000 for your hot water heater depending on the features you select. Typically, higher gallons per minute (GPM) requirements result in higher pricing.

The UEF and Heating capability measures are not as impactful on pricing.

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The installation costs of a Tankless water heater can vary between $1,000 and $3,000 depending on the amount of plumbing that is required.

If this is the first time that a tankless heater is being installed, it will cost more. In some cases, gas lines or recirculation water lines need to be installed or relocated. In some cases, vent pipes need to be installed as well.

Chosing Rinnai or Navien tankless water heater has little impact on the installation cost if you are using professional help. However there is a big difference between the brands when it comes to installation when it comes to DIY installation.

Navien markets its products to professional plumbers mainly. So it is difficult to get your hands on a system without purchasing it through your local plumber. Even if you were able to get your hands on a unit and installed it yourself, it is likely that if something happened to a DIY installed system, it could void the manufacturer’s warranty.

Cost to Operate

The energy cost to operate your tankless water heater is dependent on several factors

Heating Capacity

Both Rinnai and Navien build units that can deliver significant heating capacity. Navien models have units that can deliver up to 150,000 BTUs while Rinnai has models that deliver 200,000 BTUs. This is more than enough energy to get you all the heated water you need.

However as your need for hot water increases, the temperature must rise to meet the increasing demand, resulting in using more electricity. For equivalent heating capacity ranges, the difference in electricity usage in both units is only a few dollars per month.

Gallons Per Minute

Incoming water enters your tankless heater through an inlet valve. In the absence of a hot water tank, continuous water flow is required. Tankless Units are made with the ability to handle a wide range of flow rates from as low as 5 gallons of water per minute up to 12 GPM.

For higher flowrates, your Internal recirculating pump needs to work harder to deliver the amount of water you need. Neither of the brands have a particular obvious advantage when it comes to flowrate.


Navien Water heaters have an advantage when it comes to being energy efficient. Navien units have UEF ratings of up to 0.96 while Rinnai Units max out at approximately 0.93. The more efficient the unit is, the less energy waste which translates to more energy savings.

Rinnai has the clear edge on pricing because you have the option to buy a tankless system from any retailer you chose and install it yourself.

Life Span and Warranties

Tankless water heater systems have warranties that cover three things: labor, parts and the heat exchanger

Both brands cover installation labor and component parts for 1 year and 5 years respectively.

Heat exchanger warranty coverage however differs for both brands. Navien tankless water heater has a longer heat exchanger warranty coverage period of 15 years while Rinnai covers heat exchangers for 12 years

Rinnai and Navien cover labor and parts for identical periods (1 year and 5-year warranty respectively). But Navien covers the heat exchanger for 15 years, 3 years longer than Rinnai.

Tankless Unit Problems

From a brand perspective, both brands are quite reliable. Both brands are prone to cold water sandwich issues. But that is not unique to them.

In 2018, Navient recalled about 3,400 heaters after discovering that an optional conversion kit for converting some units from using natural gas to propane might result in dangerous levels of carbon monoxide.

This issue involved the Navien NPE-180A and the NPE-180S models

The company urged consumers who had purchased these products to immediately cease use and contact Navient for a free replacement conversion kits.

There have been no issues on record since this event.

Final Thoughts: Does Navien or Rinnai make the better Tankless Units?

You have chosen to go tankless for you Hot water heater needs. The next choice is what brand to chose – In this case, Navien or Rinnai?

For my money, I would chose the Rinnai family of tankless heaters for my hot water needs. Rinnai has been around for a very long time in the United states. Their water heaters provide the right mix of features and cost effectiveness.

When it comes to energy usage and energy consumption, their energy star rated heaters meet whatever water temperature requirements you may have without using excessive amounts of electricity.

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