Top 3 Energy-Efficient Tankless Water Heaters

Switching to energy-efficient tankless water heaters can help you save money on utility bills while doing your part to be environmentally friendly. With different brands of tankless water heaters available, it can get tricky trying to narrow down a list of the top energy-efficient tankless water heaters available.

For almost two decades, our technicians at Monkey Wrench have worked with all of the top brands of tankless water heaters to better match homeowners with a unit for their homes. After installing and servicing tankless units all over Los Angeles and the surrounding areas, we understand how hard it can be to research different tankless water heaters. 

Although there are plenty of energy-efficient tankless water heaters, these three are among the best of the best. 

• Rinnai Sensei RX Series
• Navien NPE-A2 Series
• Noritz EZ Series 

This article will review some of the highlights of these tankless water heaters and why they’re an excellent choice for homes seeking an energy-efficient water heater. Once you read through this article, you’ll gain a better understanding of what each tankless water heater offers and if it’s the perfect fit for your home. 

Let’s get started!

Which Tankless Water Heater is Most Efficient?

One thing that all of the best energy-efficient tankless water heaters have in common is that they’re Energy Star certified.

Energy Star-certified tankless water heaters meet criteria set by the United States Environmental Protection Agency (EPA) and the Department of Energy (DOE). One requirement is a Uniform Energy Factor (UEF) rating equal to or higher than 0.95, among other criteria. 

When comparing energy-saving tankless water heaters, it’s important to consider their UEF rating, which measures how effective a water heater is at converting energy into heated water. The higher the rating, the more potential energy cost savings you can take advantage of. 

The first model we’ll look at is the Rinnai Sensei RX Series, which has the highest UEF.

Rinnai Sensei RX Series

• 0.97 to 0.98 UEF rating
• Up to 11.1 gallons per minute (GPM)
• Built-in pump with Smart-Circ Intelligent Recirculation available
• App compatible through Rinnai Central
• 15-year warranty on heat exchanger, 5-year parts warranty, 5-year warranty for labor (if registered within 90 days of purchase)

As of this article’s publication, Rinnai boasts the tankless water heater with the highest UEF rating available. 

For every dollar spent on energy consumption, this Rinnai tankless water heater uses .98 cents to convert it into hot water. Rinnai’s Sensei RX line of tankless water heaters can last 20 years with routine maintenance, providing hundreds of dollars in energy savings. 

The Sensei RX has six models to choose from. Three of them have a 0.97 UEF rating, and the other three have a 0.98 UEF rating. 

Out of all the units in the Rinnai series, only two come with the built-in pump with Smart-Circ Intelligent Recirculation. The recirculation features cut down on the time it takes for hot water to reach a desired fixture, which can be scheduled through the Rinnai Central app.

Even if your home doesn’t have a return line, the other four tankless water heaters from the Rinnai Sensei RX Series can have recirculation if a pump accessory kit is installed with it. 

All Rinnai Sensei RX tankless water heaters are compatible with the Rinnai Central app, which allows you to adjust the water temperature, receive maintenance alerts, and activate vacation mode to save energy when you’re away from home for an extended time. You can even automate these features with your Amazon Alexa smart home device.

The next tankless water heater we’ll review comes from a reputable brand, Navien. 

Navien NPE-2A Series

• 0.96 UEF
• 4.3, 5.1, and 5.3 GPM available
• Has patented ComfortFlow System (internal and external recirculation pump)
• App compatible through NaviLink 
• 15-year warranty on heat exchanger, 5-year parts warranty, 1-year warranty for labor

The Navien NPE-2A Series of tankless water heaters are three different condensing units designed to provide hot water efficiently and quickly, thanks to their built-in recirculation pump. They are also Navien’s most energy-efficient tankless water heaters. 

Navien is often regarded as one of the best brands in the industry because of its reliability and many of the features it includes in its tankless water heaters. 

One unique feature is its ComfortFlow system, which has internal recirculation and an interior buffer tank that can recirculate hot water within the tankless water heater and cut down on the time it takes to reach a desired fixture.     

It also has external recirculation for homes with a return line and an accessory kit for homes without a return line. The Navien NPE-A2 has settings that allow you to schedule the recirculation based on your home’s hot water usage patterns. 

This feature can also be accessed through NaviLink, Navien’s smartphone app. The app also allows you to monitor your tankless water heater and check its water temperature, flow rate, and gas usage. You can even get a summary of your tankless water heater’s energy management by day and month. 

The freedom to monitor your tankless water heater is a feature common with the Noritz NRCR series, another eco-friendly water heating unit on this list.

Noritz NRCR Series

• 0.95 to 0.96 UEF rating
• Up to 11.1 GPM
• Includes hot water recirculation line
• 15-year warranty on heat exchanger, 5-year parts warranty, 1-year warranty for labor

Engineered in Japan, the Noritz NRCR tankless water heaters are some of the most popular in the industry. Their North American headquarters are located in Fountain Valley, southern California. 

The Noritz NRCR tankless water heaters consist of two units, which you can choose from depending on your home’s size, number of fixtures, and hot water usage. These units have integrated recirculation technology so that you can have hot water access quicker than tankless water heaters without it. 

Noritz tankless water heaters have three different recirculation modes. Learning mode schedules recirculation based on your home’s unique hot water usage, whereas the scheduling mode allows you to set the recirculation based on your needs. You can also purchase a button switch separate from the tankless water heater that lets you activate the recirculation pump on demand.

Like Navien and Rinnai, Noritz NRCR tankless water heaters are app-compatible, with the freedom to change your unit’s set water temperature, check usage, receive alerts, and more.

Which Energy-Efficient Tankless Water Heater Is Right for Me? 

Tankless water heaters are seen as more energy efficient, but even among their ranks, some units are more eco-friendly than others. Now that you know the top 3 energy-efficient tankless water heaters, you can start to narrow down your choices. With the information you gain, you can more confidently decide which one is best for you.

Since 2007, we’ve worked with dozens of different tankless water heaters from the top brands in the industry. After installing and servicing hundreds of tankless water heaters throughout Los Angeles and the surrounding areas, we’ve seen which units are the best at being energy efficient.

If you’re interested in having an energy-efficient tankless water heater installed in your home, contact us using one of the buttons below. You can also book an appointment directly through our online tankless water heater installation scheduler. 

As you weigh out which tankless water heater to choose from, take advantage of available rebates if you decide to move forward with a tankless water heater investment.