Rheem Tankless Water Heaters: Review and Buying Tips

Rheem RTGH-RH11DVLN tankless water heaterRheem tankless water heater
(photo: amazon)

Explore how Rheem tankless water heaters can deliver hot water on demand and fast, without storing hot water or taking too much 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.

By buying a Rheem tankless, 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 emissions. 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, focusing on gas-powered models.

Rheem tankless water heaters: 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 a 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 make condensing models ideal for busy homes, large homes with luxury baths, and families in need of an increased hot water supply.

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 models with the built-in recirculation pump are designed to instantly deliver hot water, 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, 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

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

Both tankless models use a circulation pump to quickly deliver hot water to the fixture 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 water usage pattern so it can meet your hot water needs when 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 models without the built-in recirculation pump come 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 the maximum power. The maximum power ranges 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 use a direct venting system with 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, providing significant savings.

Top features of the condensing water heaters - Highlights

  • The best condensing models have two stainless steel heat exchangers that deliver ultra-high thermal efficiency and longer life.
  • Some models are equipped with a recirculation system for faster hot water delivery.
  • Auto-Learn programming ensures efficient water usage.
  • Intelligent electronic controls guarantee improved performance, reliability, and safe operation.
  • Hot start programming reduces the fluctuation in hot water temperatures, which increases comfort.
  • With the maximum delivery of 11 GPM, high flow rates 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 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 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 the Mid-Efficiency series (available online) are found as RTG series 70, 84 and 95, and are recommended for 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 for 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 can still heat water with the high energy factor (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 system and deliver more power and hot water, making it great for high-demanding households.

The best models from the Mid-Efficiency series

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

All the models have the same maximum power of 199,900 BTU, heating water with a maximum temperature of 140 F and deliver hot water with a 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 water leak detection, mobile reminders, and reports.

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 are 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-sandwich."
  • 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.
  • A 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 ideal for large homes and high-demanding families, as this technology provides a continuous supply of hot water efficiently and only when 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 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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