Top 8 Tankless Water Heater Reviews

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Last updated: 
September 6, 2016

Tankless water heaters consume less energy and take up less space. They are longer-lasting than traditional water heaters and are generally easier and safer to use. If you are interested in acquiring such a system, check out our tankless water heater reviews:

Tankless Water Heater Reviews

Tankless water heaters use electricity or gas (natural and/or propane) to heat up the water we use in our household every day. To differentiate between the two, we are going to use color coding: Blue for electric tankless water heater reviews and orange for gas tankless water heater reviews. Electric tankless water heaters are considered safer and easier on the environment, but gas ones usually lower the bills considerably.

8 tankless water heater reviews

Before going through the best tankless hot water heater reviews, we want to note that choosing the type of system (gas or electric) should not only be a matter of personal preference.

Monthly costs widely vary for these two resources across the country, so look into those or ask a local specialist which might be more suitable for your area.

Rinnai Tankless Water Heater Reviews: The RUC98iN Ultra Series

Appliances in the RUC98iN Ultra Series are considerably bigger and heavier than most tankless water heaters, but this shouldn’t scare anyone away since its power is directly proportional to its size. It is ideal for larger homes with multiple consumers and can provide water as hot as 185 degrees Fahrenheit.

Tankless water heaters in the RUC98iN Ultra Series feature a control panel with buttons and an electronic display. Probably because they are aimed at households with many residents, they stepped up the game by introducing a lock function. When activated, this will prevent access to temperature settings from unauthorized residents.

For our Rinnai tankless water heater review to be complete and unbiased, we need to talk about its weak points, too. Although a state-of-the-art tankless water heater in our opinion, any appliance in the Rinnai RUC98iN series comes with a price. Installation is tricky and maintenance can only be performed by Rinnai employees if you want to keep its warranty.

Rheem Tankless Water Heater Reviews: The RTE 13 & the RTG-64XLN

There are plenty of Rheem tankless water heaters available. We selected the most interesting ones from each category, gas, and electric. Here they are:

The RTE 13

Rheem’s RTG-64XLN delivers up to 6.4 gallons of hot water per minute, which accounts for hassle-free simultaneous usage. Unlike other models presented in our article, Rheem’s gas tankless water heater is an appliance that should be installed outdoors. It can be operated manually or remotely and has plenty of safety systems. However, it is not ideal for large homes and commercial or industrial buildings.

To sum up our Rheem tankless water heater review, we want to note that it is efficient, but not extremely reliable when temperatures drop. Given that its unit is to be installed outdoors, temperature fluctuations will strongly influence its functionality.


We want to start off our Rheem RTE 13 electric tankless water heater review by mentioning it only has a peak flow of 4 gallons per minute. Therefore, it is best used for small apartments and houses with a single occupant, as a point-of-use appliance and connected to a maximum of 3 fixtures.  This makes it a great choice for RVs, garages which also serve as workspaces, etc. The RTE 13 is compact, energy-efficient, and long-lasting, but not at all recommended to large homes.

Navien Tankless Water Heater Reviews: The NPE-A Series

The NPE-A Series has an admirable efficiency ratio of 98% and is able to reduce poisonous and harmful emissions to a quarter of those registered by other competitors. The “weakest” model, the 180A, can heat up to 8.5 gallons of water per minute while the NPE-A Series leader, the 240A, can go beyond 11 gallons of hot water per minute.

To put our Navien tankless water heater review in perspective, the average GPM (gallons per minute) output for tankless residential water heaters is between 5 and 6 GPM. The only downside we are aware of is the difficulty of finding an authorized technician. This means repairs usually take longer and are a bit costlier than with other similar appliances.

Noritz Tankless Water Heater Reviews: The NRC661-DV-NG

The basic NRC661-DV-NG can deliver up to 6.5 gallons of hot water per minute if heating the water by 30 degrees Fahrenheit. However, heating up the water with 70 degrees will halve the hot water flow. Noritz’s NRC661-DV-NG has an average efficiency rate of 93%, is durable, and reliable. However, it does have its weak points:

This tankless water heater is only recommended to small houses or flats with about 2 residents, and/or in warmer areas. Low temperatures heavily affect this heater’s performance and serving 2 running showerheads at a time can be a challenge. Another worrying fact on this Noritz appliance is its nitrogen oxide emissions which, although low, surpass industry’s standards.

To conclude the Noritz tankless water heater review, we want to note another aspect that might matter for some. The unit comes with a basic temperature control panel which allows users to choose among 3 temperature options. However, the separate remote features a display and 9 temperature options.

tankless water heater reviews for gas and electric systems

Takagi Tankless Water Heater Reviews: The T-KJr2-IN-NG

This model’s smartest feature is the air-to-fuel sensor which calculates and implements the best air/fuel ratio. This improves its efficiency, yet it still only has an 82% efficiency rate – much lower than other tankless water heaters mentioned in our article. Other than this, Takagi’s appliance has all the required protection and safety mechanisms – and a few extras.

Its temperature settings are standard: 9 temperature steps between 100 to 140 degrees Fahrenheit. It works best in warm climates where it doesn’t have to heat up the water more than 35 degrees over its initial temperature. Under these conditions, it is able to provide over 6.5 gallons of hot water per minute.

We want, to sum up our Takagi tankless water heater review by mentioning that, although of average performance, it can only serve two bathrooms at a time when the weather is warm. When temperatures drop, this will be a challenge if not impossible.

Bosch Tankless Water Heater Reviews: The Therm 520 HN

The Bosch tankless water heater makes good use of its patented hydropower ignition system to make a system that functions during power outages. Its top flow rate can be registered at a little over 5 gallons per minute and with a minimum water pressure of 30 PSI. Its efficiency peaks when heating up water no more than 35 degrees over its current temperature.

However, our Bosch tankless water heater review would not be complete if we didn’t mention its downsides. Although the Therm 520 HN has a modern, metallic exterior, some of its inner components do not enjoy the same luxury and can have significantly shorter lifespans. The plastic water valve housing can freeze up when temperatures significantly drop outside if the unit is placed in colder rooms, and so can its hydrogenation unit. This can become a major problem since the hot water supply can be completely cut off.

EcoSmart Tankless Water Heater Reviews: The ECO 27

EcoSmart’s ECO 27 is the most customizable tankless water heater on the market at the moment. Customers can adjust the water temperature through a digital panel in 1-degree increments. If used in warmer climates, the ECO 27 can be as efficient as 99.8%. Even though the model is not Energy Star certified, its self-modulating and permanent readjusting function can save considerable amounts of resources in the long run, even in the coldest climates.

The unit is compact (18 x 17 x 3¾ inches) and weighs less than 14 pounds. Nevertheless, its contemporary design allows customers to place the unit in full view without disrupting the aspect of a room. Another relevant aspect for our EcoSmart tankless water heater review is its maximum flow rate of 6 to 7 gallons per minute. This enables the ECO 27 to serve up to four showers and a sink at a time when working at maximum capacity.

Marey Tankless Water Heater Reviews: The 16L NG ETL

Although compact (14 inches wide and less than 22 tall), Marey’s 16L NG ETL can heat up to 5.5 gallons of water per minute. It has a rustproof, leak-resistant water heater system which also features a smart gas pressure buildup protection and an anti-combustion mechanism. This makes the system efficient and safe. The design is simple and modern, but this doesn’t matter much since it can be installed behind a cupboard or in other discreet places.

The 16L NG ETL can be set to automatic or manual mode, the latter being excellent at conserving resources. Although a bit sensitive and more difficult to get accustomed to, using the manual settings is a must if you want to lower gas consumption. We want to conclude the Marey tankless water heater review with its stronger feature: The price. The 16L NG ETL is considerably cheaper than its competitors while still performing more than decently.

tankless water heater reviews 2016


There are no general rules when it comes to heating; It all boils down to your location and cost of the available resources. Tankless water heaters can be a good for residential, commercial, and industrial buildings. However, they can also be inefficient in colder areas or in large homes.

As you probably noticed, we included much more tankless electric water heater reviews than of tank  less gas water heater reviews – and there is a logical explanation for this. Methane and propane water heaters are generally cheaper to operate in the long run and can be more efficient. However, electric power is more available than gas – in fact, electric water heaters can also be used on boats, RVs, etc.

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