Navien Vs Rheem: The Ultimate Guide

Selecting a tankless water heater unit for your home is significant decision. At a minimum you’ll be spending a few thousand dollars on the purchase which means you’ll want a hot water heater that will not only meet your hot water usage needs, but will last for a long time.  

Among the brand options you have are Navien and Rheem. Both brands can be found in millions of households around the United States and beyond which speaks to their reliability. But there are differences between both brands that may make you select one of the other.

In this post, we will explore both tankless water heater brands and help you chose the one that will work best for your application. 

Photo Courtesy Hebron Stores

Navien or Rheem Which has the better Tankless Heater Brand?

The Rheem Manufacturing Company was founded in 1925 by two brother, Richard and Donald. Rheem makes much more than tankless hot water heaters. The company also manufactures tank hot water heaters,  boilers, air handlers and humidifiers. In fact, in many homes, the Heating and Air Conditioning systems are made by Rheem.

 The diversity in Rheem’s product line has made it a staple in almost every home in the United States. The company also has significant global presence which allows it to take advances made in technology as regulations change, especially when it comes to energy efficiency from one market to the next. 

Navien, Originally founded in Japan in 1978 has been selling tankless water heaters in the United States since 2006. Navien’s specialty in the water heater segment is with Tankless Heater units. Navien does not make residential heated water tanks. 

Navien also makes boilers and sells its products across the globe. 

From a brand recognition perspective, Rheem has the edge over Navien. Rheem’s products can be found in multiple areas of the home. Whether you have a tank or tankless models, or an AC system it is more likely that you are familiar with Rheem than you are with the Navien brand. 

Navien vs Rheem Which is More Energy Efficient?

Tankless heating units whether they are powered by gas or electricity require a lot of power to deliver the hot water needed in a short period of time. This makes choosing the more energy efficient option an important consideration. 

Rheem makes a variety of tankless units from Condensing Gas Tankless Water heaters to Electric and even Hybrid Units. This variety means that you can find a product that meets your energy efficiency needs, depending on the price of the unit.

For instance, the Performance Tankless Electric 24-27kw  has an impressive efficiency rating of 99.8%, while the Tankless Mid Efficiency 95 Direct Vent Indoor has an efficiency rating of 82%.

Navien’s tankless unit also boast a strong efficiency rating of up to 96%. 

Rheem Tankless Units have an advantage over Navien’s units when it comes to efficiency.  Rheem’s units boast a wider efficiency range from 0.82 UEF to 0.99UEF (99.8%). Navien’s units have a top end range of 0.96 UEF.

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

Navien water heater

Water Heater Price

It can be difficult to do direct comparison on pricing between Rheem and Navien Tankless Water Heater Units. Depending on what features you select pricing can vary widely. Electric water heaters tend to be more expensive than Gas Tankless Water Heaters.

Also, the higher the gallons per minute requirement you have, the more expensive the unit is likely to be. 


The cost to install you tankless water heater will largely depend on if you chose of use a professional or decide to do it yourself. In general, Installing your water heater will cost you between $1,000 and $3,000. You can expect the higher end of the cost range if  you use a professional.

Another factor that influences the cost to install is if you need to adjust the position of gas lines or water lines. From a safety perspective, if you are installing Tankless Gas Water heater, I typically recommend that you use a professional. 

The most important factor influencing the cost to install you hot water unit is product distribution. 

What do I mean? Well, you can only buy Navien Tankless Water heaters through a plumber. The company does not sell directly to the public. Rheem Tankless systems on the other hand can be found on Amazon or at Home Depot or Lowes.

Rheem Tankless systems have a clear edge on cost if you choose to install the system yourself because you can buy them online or at your local home goods store. Navien Tankless Units are only sold through local plumbing and heating companies. 

Operating Costs

The primary determinant of the cost to operate any appliance in your home is whether you are using natural gas or electricity. In general natural gas is cheaper to use for each unit of energy consumption. 

Heating Capacity

Tankless Water Heaters typically have a heating capacity that ranges between 150,000 BTUs and 200,000BTUs. For equivalent BTUs your energy savings will be higher if you chose a Tankless Gas Water Heater over one that is powered by electricity.  

Both Rheem and Navien have tankless units that span the range for heating capacity

Gallons of Water Needed (Gallons per minute)

Tankless Units require continuous water flow since they do not have tanks. This requires energy. The higher the flowrate required, the more the energy cost will be because the internal recirculating pump operates at higher revolutions per minute (rpm) to deliver the hot water supply needed.    The heating capacity and flow rate determine how fast your unit gets to the desired water temperature. Both Rheem and Navien have units that can support whatever flowrates are needed for home use.   


Both Rheem and Navien are Energy Star certified across all of their tankless units. The energy star certification measures the ratio or energy used to energy wasted. 

It is important to note that the higher the efficiency UEF of the unit you chose, the less energy it will require to heat because there is less energy waste. 

Rheem’s tankless water heater units have an advantage when it comes to efficiency. Their efficiencies run as high as 99.8%. Navien’s highest rated units have a high end range of 96%. 

Your yearly energy cost will be lower if you choose a unit powered by gas with a lower flow rate and higher efficiency. 

Life Span and Warranties

Tankless water heaters can last for more than 20 years of maintained properly. Over time, certain components can wear out. But they are replaceable. 

Rheem’s electric tankless water heaters carry 1-year warranty on labor and 5-year warranty on parts. The company’s gas tankless systems also carry the same warranty.

Navien’s warranty on parts and  labor are also 1-year and 5-years respectively. 

But Navien separates itself from Rheem by having a 15-year warranty on its Stainless Steel Heat Exchanger. This makes sense because stainless steel does not corrode and will therefore have a longer life than heat exchangers make from other materials.

Navien Tankless Hot Water Heater Units are built to last longer than Rheem’s because they are made using more durable materials. 

Final Thoughts

Choosing between Navien and Rheem Tankless water heating systems is not an easy decision. Rheem has a more recognizable brand and can be cheaper to install. But Navien’s tankless water units are are built to last longer. 

If you preference is for product variety, you will have more options with Rheem than you will with Navien.

After taking all these factors into consideration, my personal preference would be to chose Rheem over Rinnai due to product availability and the option to install it myself, saving me money on the purchase.