Rheem Tankless Water Heaters
Review and Buying Tips

Explore how Rheem tankless water heaters can deliver hot water on demand and fast, without storing hot water or taking too much of your space, while utilizing advanced electronics, precise temperature control, and smart home integration technology.

Rheem tankless water heaters are designed for homeowners who prefer small, compact, but powerful units equipped with cutting-edge technology.


Because customers will get a space-saving model that can provide ultra-efficient water heating with the continuous supply of hot water, resulting in lower operating costs and reduced gas emission. All that, plus advanced diagnostics for troubleshooting.

All today's tankless models from Rheem can be connected to EcoNet, which will allow homeowners to take advantage of the smart features.

This review covers Rheem tankless water heaters designed for residential applications, with the main focus on gas-powered models.

If you require professional assistance, contact a local water heater expert today!

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Models review

There are two groups of Rheem gas-powered tankless water heaters for residential use and whole-house water heating: condensing (Prestige series) and non-condensing (Classic series).`

Prestige condensing series

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Rheem gas tankless water heaters with the condensing technology are ultra-efficient and ultra-low NOx models that are equipped with two quality stainless steel heat exchangers and high-power eco-friendly gas burners, delivering sufficient amount of hot water no matter the climate or temperature fluctuation.

The energy factor of up to 0.96, high power, and water flow of up to 11 GPM makes condensing models ideal for busy homes, also large homes with luxury baths, and families that are in need of an increased supply of hot water.

These tankless heaters are coming from the Prestige series and can be further divided into two groups - with the recirculation pump, which is the best of all, and the group without the recirculation system.

Rheem Prestige series with the built-in recirculation pump is designed to deliver hot water instantly, saving you time, energy, and water. They come in two sizes and are powered by natural gas and propane.

These tankless models are designed for indoor use only, utilizing the 2-pipe direct venting system with lengths of up to 100 ft, while using either indoor or outdoor air for combustion.

The best tankless water heaters from Rheem are:

Model/Specs Venting Gas Input
Flow Rate
EF # of showers
RTGH-RH10DVL (N/P)* Indoor
Direct Vent
0.26-10 0.94 3
RTGH-RH11DVL (N/P)* Indoor
Direct Vent
0.26-11 0.94 4

N – natural gas
P – propane gas

As opposed to the rest of tankless water heaters from Rheem, the Prestige series with the built-in recirculation comes with the large temperature controller that is built into the front panel, allowing easy navigation from programming to problem diagnostics.

Both tankless models use a circulation pump to deliver hot water to the fixture fast and can be activated at specific times for enhanced comfort and convenient use. Also, the auto-learning programming system can "see" and learn about the pattern of water usage so it can meet your hot water needs when it is needed.

The units are very safe. They are equipped with the sealed combustion direct vent system and direct electronic ignition, and include many safety elements, from the flame rod to temperature sensors and freeze protection.

And, as an additional safety factor, built-in water and gas leak detection system shuts down the unit and provides the error code, keeping your family safe anytime.

Rheem Prestige series without the built-in recirculation pump comes in four sizes that can be installed indoors or outdoors, using natural gas and propane. Those models are designed with the modulating gas valve so the heater can operate from its minimum to its maximum power. The maximum power is in the range from 120,000 to 199,900 BTU while the water flow is from 6.8 to 9.5 GPM (depending on the model), making them ideal for use in homes with up to four showers.

Indoor models are using a direct venting system with the pipes up to 150 ft. in length, which is longer than the pipes from the above models.

These tankless models do not have the remote controller built-in but are pre-wired, so you can conveniently use your device.

These are the available models listed from the smallest (least powerful) to the largest (highest gas input):

  • RTGH-68
  •  RTGH-84
  •  RTGH-90
  •  RTGH-95

Due to the ultra-high energy factor (EF) and low gas emission, all Rheem condensing water heaters are "green" and Energy Star compliant that provide significant savings.

Top features of the condensing water heaters - Highlights

  • The best condensing models are equipped with two stainless steel heat exchangers delivering ultra-high thermal efficiency and longer life.
  • Some models are equipped with the recirculation system for faster hot water delivery.
  • Auto-Lear programming ensures efficient water usage.
  • Intelligent electronic controls guarantee improved performance, reliable, and safe operation.
  • Hot start programming reduces the fluctuation in hot water temperatures, which increases comfort.
  • High flow rates, with the maximum delivery of 11 GPM, allow sufficient hot water supply for houses with more than four showers.
  • The Guardian overheat film wrap is used for additional safety.
  • The EZ-Link cable connects two units into one system for the higher flow rates and power.
  • Option to manifold up to 20 units to deliver more hot water.
  • Flexible installation where the indoor models can use horizontal or vertical venting with up to 150 ft. in length. Outdoor models are ventless, so there is no venting work required. Indoor units can use PVC vent pipes for more savings.
  • The self-diagnostic system allows easy troubleshooting.
  • A remote control enables temperature adjustments to up to 185 F on some models.
  • 12-year warranty on the heat exchanger and 5 on parts.

Mid-Efficiency models

Rheem tankless water heaters from Mid-Efficiency series (available online) are found as RTG series 70, 84 and 95, and are recommended for those homeowners who do not want to spend a lot of cash but want to take advantage of the tankless technology and advanced electronics. Those models can also be used for smaller vacation homes with one bathroom and larger homes with several bathrooms, delivering hot water up to 9.5 GPM.

As the condensing series, this group also contains indoor and outdoor models, while the main differences are that they do not use two stainless heat exchangers as condensing, but one, which is made of copper, and the efficiency is significantly lower – around 0.82.

The mid-efficient heaters are designed as non-condensing but are still able to heat water with the high energy factor (when compared to tank-type) and provide low cost and environment-friendly operation.

The digital remote controller ensures computerized operation with better accuracy and self-diagnostics.

As it can be using the cable connection, two models can be connected into one and deliver more power and hot water, making it great for high demanding households.

The best models from Mid-Efficiency series

The largest models from the Mid-Efficiency series of tankless water heaters are RTG-95, which are designed with the direct venting for indoor installation, ventless for outdoor installation, with the included EcoNet and recirculation pump (RTG-RC95DVLN).

All the models are having the same maximum power of 199,900 BTU, heating water with a maximum temperature of 140 F and deliver hot water with the flow of up to 9.5 GPM. This is sufficient for homes with up to 4 baths.

And if you need to control your new Rheem tankless water heater online using the WiFi, buy an RTG-95DVELN (indoor) or RTG-95XELN (outdoor), so you can enjoy smart home features, such as the water leak detection, mobile reminders, and reports.

If you require professional assistance, contact a local water heater expert today!

Feature highlights

  • On-demand water heating uses one copper heat exchanger that provides excellent resistance to the corrosive water action.
  • Ultra-Low NOx burner reduces the emission of greenhouse gases.
  • Intelligent electronic controls ensure accuracy and safety.
  • Three sizes available providing the water flow from 0.26 GPM to a maximum of 9.5 GPM - plenty of hot water for houses with 4 bathrooms.
  • Small, compact size that saves the floor space as it installs on the wall.
  • Self-diagnostic helps in problem-solving.
  • Digital display of the hot water temperature and the error codes.
  • Hot start programming increases comfort by reducing the "cold water-sandwiches".
  • The Guardian overheat film wrap (OFW) protects from overheating and element failure.
  • The EZ-Link cable allows the connection of two units into one system, therefore providing more hot water, which is excellent for houses with luxury baths, spas, oversized tubs...
  • Option to manifold up to 20 units.
  • Flexible vent installation.
  • Remote control allows temperature adjustments up to 185 F on some models.
  • 12-year warranty on the heat exchanger and 5 on parts, in residential applications.

Rheem electric tankless water heaters

Rheem tankless electric units (available on amazon.com) Rheem tankless electric units are used for point-of-use service and are usually installed under the kitchen sink or in the bathroom.

These models can also be used in the garage, barns, workshops or offices, or distant sinks.

Rheem manufactures several models, from as low as 3 kW to large 27 kW units designed to provide up to 5 gallons of hot water per minute.

The main features include the low-flow activation, modulating power, LED power indicator, and a 10-year warranty.

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Rheem tankless water heaters are an ideal solution for large homes and high demanding families, as this technology provides a continuous supply of hot water, efficiently and only when it is needed. The great things about tankless are the use of sophisticated technology, advanced features, and professional-grade quality.

Homeowners can now use multiple showers, do the laundry and dishes without worrying about the supply. The best models come with the recirculation and can even provide hot water instantly, so there are no unpleasant cold water bursts.

The state-of-the-art design offers flexible installation that can accommodate two gas pipe sizes and longer PVC venting. Rheem tankless is safe and smart.

And when the tankless is combined with condensing technology, users will save a lot of energy and money, where the operating costs are below $200 per year (according to the manufacturer).

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