Shower head

Shower head (Photo by Pixabay on Pexels)

Between dishes, showers, and laundry, busy homes need a reliable source of hot water. Caught between the desire to increase sustainability and having enough hot water when you need it, some homeowners have turned to tankless water heaters as their solution. Without adequate hot water, enjoying a nice long shower just isn’t the same. The best tankless water heaters provide numerous benefits, including on-demand hot water, energy efficiency, space savings, and a longer lifespan compared to traditional tank-based heaters.

Switching to a tankless water heater offers compelling reasons for homeowners to consider this upgrade. Firstly, they eliminate the need to wait for a storage tank to refill and ensure a continuous supply of hot water whenever it is needed. They are also more energy-efficient, as they heat water only when necessary, avoiding the standby heat loss associated with traditional tank-based heaters. This not only reduces energy consumption but also translates into lower utility bills. Furthermore, tankless water heaters take up considerably less space, making them ideal for homes with limited square footage. Their compact design allows for flexible installation options, such as mounting on walls or even outdoors. Plus, tankless units often boast a longer lifespan compared to their tank-based counterparts, providing years of reliable hot water without the need for frequent replacements. Making the switch to a tankless system could be a worthwhile investment for homeowners.

Why not enjoy a nice hot shower? After all, some of our best ideas come about when we hop in the shower. In fact, many people have been in the shower when that brilliant, light bulb moment suddenly strikes! It can seem like a strange place to have great ideas, but researchers say “shower thoughts” are pretty common. So, why do so many people get a spark of creativity while washing up? Study authors say the mind actually works better when there’s a moderate level of engagement. Simply put, doing something that’s truly “boring” and doesn’t require any thought does not spark more creativity than a simple task which requires a small amount of the person’s attention. “Say you’re stuck on a problem,” says Zac Irving, a University of Virginia assistant professor of philosophy. “What do you do? Probably not something mind-numbingly boring like watching paint dry. Instead, you do something to occupy yourself, like going for a walk, gardening, or taking a shower. All these activities are moderately engaging.”

Apart from the folks that like a cold shower, hot water is absolutely essential for washing up. Plus, it is needed in busy modern homes in particular for tasks like laundry, running the dishwasher and more. That’s why StudyFinds compiled a list of the best tankless water heaters to upgrade your home. Let us know your opinions in the comments below!

The List: Best Tankless Water Heaters, According to Experts


1. Steibel Eltron

For consumers in the know The Steibel Eltron is a highly regarded unit. Forbes offers up details, “The Stiebel Eltron DHC Trend Point-of-Use Electric Tankless Water Heater is just what it sounds like. It provides nearly instant hot water at a single location, and it’s great at doing so. It takes the top spot on our list, and with its selling cost, it won’t break the bank. There are many models to choose from to meet your needs. The one we reviewed is the DHC 10-2. Offering 32,757 BTUs of heating capacity, it can provide up to six gallons of hot water per minute. Stiebel Eltron has been creating water heating solutions since 1924 and they back up their products with 10 years of warranty protection against leaks, and three years against defects. This model requires 240 volts and a 40 amp circuit breaker to deliver 9,600 watts of heating power. To protect itself from burnout, it features a flow rate monitor that cuts power to the heating element in the event of a water supply disruption.”

Stiebel Eltron Tankless Heater – Tempra 36 Plus – Electric, On Demand Hot Water, Eco, White Style:Tempra 36 Plus (36 kW)
Stiebel Eltron Tankless Heater

According to This Old, “We liked that this tankless water heater has a high flow rate for an electric unit, delivering 1.5-4.5 gallons per minute (GPM) of water. Additionally, its intelligent self-modulating technology and compact size ensure ongoing energy savings with no venting required.”

Modern design and thoughtful functionality are described by Family Handyman: “If you’re looking to go electric and wondering about the best tankless water heater for the money, consider the Stiebel Eltron Tankless Water Heater. This model has an advanced flow control feature to keep water consistently hot during ongoing use, so your shower won’t fluctuate in temperature or go cold. Plus, its digital display lets you see the accumulated cost savings, so you can see how much money you’ve saved by installing a tankless water heater. The 36 Plus model has a flow rate of seven and a half gallons per minute in warmer climates, which is plenty for most homes.”

2. Rheem Tankless RTEX-18

Offering a balance of quality and value, Popular Mechanics rates Rheem as follows: “Packing 240 volts, this electric water heater can put out as much as 4.4 gallons of water per minute. This tankless water heater allows you to adjust the water temperature yourself, thanks to its sleek LED display. And it can be easily installed on an inside wall, which means it likely won’t take up as much space as your standard tank heater.”

Rheem 18kW 240V Tankless Electric Water Heater
Rheem 18kW 240V Tankless Electric Water Heater

According to Bob, “Rheem has tremendous experience with both gas and electric tankless water heaters. The high-quality RTEX-18 is rated for up to 4.4 GPM and offers advanced self-modulation, helping it achieve an efficiency rating of 99.8 percent. It can raise water temperature for one or two showers well beyond the recommended 110 degrees Fahrenheit level, making it an impressive yet economical choice for modest homes. It is widely recognized as being easy to install. Operation is simple, with a clear display and large dial offering control in single-degree increments. Brass-topped heating elements offer high durability and are easy to replace should the need arise. This Rheem model is an 18kW unit requiring a 240V supply and two 40A breakers.”

3. Rinnai Indoor Tankless

Offering a unique set of functions, the Rinnai Indoor Tankless has a lot going for it. According to The Spruce, “The Rinnai RL75iN is our pick for a natural gas tankless water heater since it offers reliable performance, impressive heating capabilities, and the ability to be installed in just about any indoor space, including an attic or crawl space. The Japanese manufacturer of water heaters is frequently praised for its reliability, and it doesn’t hurt that the heat exchanger on the RL75iN carries a 12-year warranty. This model is capable of a maximum flow rate of 7.5 GPM and generates 180,000 BTU of heating power. For climates with groundwater temperatures from 47 to 67 degrees F, the RL75iN can keep water flowing to three or four fixtures at the same time.”

Rinnai RL75IN Tankless Hot Water Heater, Indoor
Rinnai RL75IN Tankless Hot Water Heater, Indoor

As a gas powered option, “This tankless water heater uses gas instead of electricity for a higher flow rate. It’s installed inside to prevent cold temperatures from affecting its heating efficiency. With its flow rate of 7.5 GPM, we think it’s ideal for medium– and large-sized homes,” writes This Old

For many consumers, gas is a better fit for water heating needs as compared to electric. For them, this may well be the best water heater available. According to Family Handyman: “On the fence about upgrading to a gas-powered tankless water heater? Consider this: You’ll likely never run out of hot water with the Rinnai Natural Gas Tankless Water Heater, which has a capacity of almost 10 gallons per minute. That translates to six running water fixtures at once, which is enough hot water for even the busiest homes. Plus, it’s the size of a small suitcase, so that it can fit almost anywhere and it comes with smart options if you purchase the separate Rinnai module for Wi-Fi connectivity.”

4. Ecosmart 11

The Ecosmart 11 is best suited for smaller homes in more temperate climates. Thomas Net claims: “The EcoSmart ECO 11 tankless water heater may be small and reasonably priced, but it’s definitely not lacking in features that some of the more expensive models have. The 13 kilowatts of power from this electric tankless heater are sufficient to supply an average bathroom or kitchen faucet with hot water. It’s an economical option too, as it only heats water when it’s needed. In addition to providing hot water quickly and reliably, it will also reduce energy use by about 60%, as its patented self-modulating technology gives this tankless water heater the ability to optimize its energy output on its own. EcoSmart offers a lifetime warranty on the element, electronics, and exchanger on this particular model, but only if a professional or certified plumber installs the system.”

EcoSmart ECO 11 Electric Tankless Water Heater, 13KW at 240 Volts with Patented Self Modulating Technology
EcoSmart ECO 11 Electric Tankless Water Heater

This Old also details the following: “This tankless water heater has a low flow rate of 1.3-3.1 GPM, which we think is enough water for a small household of one or two people. The unit is capable of providing consistent performance within just one degree of the temperature you select.”

Bob adds, “Those who live in compact modern homes will want to take a close look at the EcoSmart ECO 11. Rated for a maximum of 3.1 GPM, this affordable unit can provide constant hot water for a shower and low-flow faucet simultaneously. It is one of few electric tankless water heaters that uses the accurate UEF standard, with outstanding efficiency of 99.8 percent. As with all the models in the EcoSmart range, the ECO 11 has self-modulating technology. The DOE estimates it saves around 50 percent on hot-water costs per year. The digital display provides temperature-control adjustment in 1-degree steps, anywhere from 80 degrees to 140 degrees Fahrenheit.”

5. Bosch Tronic 3000

The Bosh Tronic 3000 is a smaller unit that can be placed next to a fixture. Thomas Net states, “Solving the problem of having to wait for hot water at a sink that’s far away from the main heating source, the battery-powered Bosch Tronic 3000 is designed for covert installation, able to go up wherever you like, and as close to the fixture as is convenient. While waiting for the central water heater to heat up, this unit can supply up to four gallons of hot water to a fixture. Water waste is decreased, and wait times are shortened, too. These point-of-use heaters have multiple uses, including as standalone hot water units for a single sink, as supplements to an already-existing tankless water heater that is far from the sink, and as a buffer installed in line with tankless water heaters that experience intermittent cold water. Many buyers use them in their showers, which are often located some distance from the central heating system, while others use them in private sheds, or backyard barbecue areas.”

Bosch Electric Mini-Tank Water Heater Tronic 3000 T 2.5-Gallon (ES2.5) - Eliminate Time for Hot Water - Shelf, Wall or Floor Mounted
Bosch Electric Mini-Tank Water Heater Tronic 3000

According to, “It has a small 2.5-gallon water tank that provides an adequate hot water supply to a point-of-use (POU) fixture, such as a shower, kitchen sink, or faucet. This mini tank electric water heater can be used in a number of ways. It can produce sufficient hot water for a single sink. You may also use it to complement an existing water heater that is placed some distance away from the location where hot water is required. This offers instant access to hot water. Additionally, it may be installed in-line with a tankless water heater, which generally encounters intermittent “cold water sandwiching.” Thanks to this mini tank water heater, you do not have to wait more than a minute and a half for hot water to flow through your faucet. Bosch offers a limited warranty of six years on the unit and two years on components.”

Money stresses the efficiency of on-location heating for water sources. “Gas or electric tankless water heaters are usually installed in the basement or utility room, and they supply hot water to all faucets and appliances around a home. On the other hand, a point-of-use water heater is installed at a specific water source, such as a shower or sink, and only heats the water at that location. This may seem unnecessary if you already have a central water-heating system. But sometimes heated water takes up to 10 seconds or more to reach all parts of the house. This delay can waste water in the long run, and this is where point-of-use heaters come into play. The Bosch Tronic 3000 can be installed under a sink, inside a cabinet, or in any other concealed location (as long as its supply line reaches its target faucet). The unit will provide up to four gallons of hot water at that fixture until hot water from the main heater arrives. This cuts down on long waits and reduces the amount of water that’s wasted.”

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Note: This article was not paid for nor sponsored. StudyFinds is not connected to nor partnered with any of the brands mentioned and receives no compensation for its recommendations.

About Alan Corona

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StudyFinds publishes digestible, agenda-free, transparent research summaries that are intended to inform the reader as well as stir civil, educated debate. We do not agree nor disagree with any of the studies we post, rather, we encourage our readers to debate the veracity of the findings themselves. All articles published on StudyFinds are vetted by our editors prior to publication and include links back to the source or corresponding journal article, if possible.

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  1. Burnice Bauch says:

    I just had a look at your blog post about the best tankless water heaters, and it’s a comprehensive guide for anyone looking to invest in this technology. The post provides a list of top tankless water heaters, highlighting their features, efficiency, and performance. It’s great to have such a resource that helps consumers make informed decisions when choosing a tankless water heater that suits their needs. Thanks for sharing this helpful blog post, as it assists readers in navigating the options available in the market and finding the best solution for their homes. Keep up the good work!

  2. Yeti75 says:

    The Navien NPE230A2 beats all of these, hands down.

  3. Jim says:

    Both Navien and Noritz are better than all on the list. This list sucks.