Tankless Water Heater Reviews

A tankless, or on-demand, water heater only heats water when you need it. These water heaters give you an endless source of hot water, all while saving money on energy costs. Tankless water heaters heat water directly without the use of a storage tank. When a hot water tap is turned on, cold water travels through a pipe into the unit. We know that purchasing a water heater requires much thought. tankless.best can help you select the best water heater.

How We Choose Products For Our Tankless Water Heater Reviews

Wondering how we’ve chosen the products that we review on tankless.best? Curious to learn more about the process of water heater reviews? Get the inside scoop now – here are the factors we take into account when choosing products for our water heater reviews.

Consultation With Plumbers And Professionals

First, we started the process off by interviewing professionals in the plumbing industry – from water heater installers to HVAC support staff, industry customer service representatives, and more.

Professional plumbers are a reputable source of information for our water heater reviews – so we’ve considered their input, brand preferences, and other factors closely while picking out products to recommend to our readers.

By compiling a list of brands and models that were repeatedly mentioned and approved by plumbing professionals, and cross-referencing them with the products that showed up in other buying guides, and had great online reviews, we were able to determine which products will work the best for you, your home, and your family – and use this information to develop informed, useful, and comprehensive tankless water heater reviews.

Tankless Water Heaters – Top 6 Best Tankless Water Heaters

1Rinnai water heaters brandRinnai RUC98iNINDOOR installation only. Fuel Type… Concentric or PVC venting option. Up to 0.96 Energy Factor/Up to 0.92… View now
2Stiebel Eltron water heaters brandStiebel Eltron Tempra Plus 36 kWDigital temperature control. Proven reliability. No venting required. DRAWS 150 A. Requires minimum 300 A… View now
4TAKAGI water heaters brandTakagi T-KJr2-IN-LPVent Type: Direct Vent; Water Connections… Product Weight: 38 lbs; Safety features… 140,000 BTU… View now
5Rinnai water heaters brandRinnai RUC98iPConcentric or PVC venting option. Up to 0.96 Energy Factor. The space-saving design allows installation… View now
6Rheem water heaters brandRheem RTGH-95DVLN94-Percent Energy efficient with stainless steel… Intelligent electronic controls designed to increase… View now

Brands With Great Reputations

We’ve made it a point to seek out brands that are reputable and well-known on the market. This includes brands like Bosch, Eccotemp, Stiebel Eltron, Takagi, Rheem, Marey and so much more. We’ve considered brands from all over the world, to give you the most comprehensive set of water heater reviews anywhere on the internet.

But we didn’t stop there. Not all tankless water heaters are alike, even from the same manufacturer. So we’ve looked at units of all different sizes, fuel types, and designs. By poring over reviews on websites like Amazon, customer feedback on Lowe’s and The Home Depot, Menard’s, and in-person interviews with owners of specific tankless water heater units, we’ve been able to compile a comprehensive list of each unit’s benefits – and shortcomings – in our water heater reviews.

We’ve used this information to determine which units offer the best value for the money – providing reliable performance with low yearly maintenance costs, and energy-saving designs that will help pay for themselves over time.

Special Features

Tankless water heaters are not all about flash and special features, but we have noted units that incorporate some special features. And, where appropriate, these features can help you get better performance, higher energy-efficiency, and much more. Some of the features that we looked at included:

Computer-controlled monitoring (smart home)

Using microprocessors, some “smart” tankless water heaters can easily read incoming water temperature and then adjust the energy output of the burner or electrical element automatically.

What does this mean? It means you’ll get a more steady water temperature, and use less energy. In the winter, for example, when your water is at an ambient temperature of 60 degrees Fahrenheit before entering the element, the microprocessor can read the temperature – and add 35 degrees of warming power to bring it to your preferred temperature, say 100 degrees Fahrenheit.

Conversely, in the summer, if the water is at an ambient temperature of 80 degrees, the microprocessor can add just 20 degrees of heat – which ensures you always use minimal energy for your hot water at all times.

Water flow control

If you start running more hot water than your tankless heater can produce at any given time, one of two things will happen – the temperature will drop, or the flow rate will decrease.

With flow rate control, the latter is what will occur. Your flow rate will slow, but the water will still be at the proper temperature. In our opinion, this is a great feature – because showering in a hot, yet reduced flow of water seems preferable to facing a lukewarm, or even cold shower.

Tankless water heater energy factor

The energy factor is a measurement of a water heater’s efficiency, ranked on a scale from 0.00 to 1.00. During our water heater reviews, we found that the energy factor for electric units was typically between 0.96-0.99. Gas units have more variability, ranging from 0.64-0.94.

The higher the number, the more efficient the water heater is. However, more efficient heaters can be much more expensive. In our water heater reviews, we’ve done our best to strike a balance between the long-term value of a lower power bill and the higher up-front costs of energy-efficient units, to help you choose the right unit for you.

Condensing technology

This is a feature found only in gas-based units, which allows hot gases released by the process of heating water to be recaptured and used to heat the water again – enhancing efficiency, and reducing the temperature of exhaust gases. Because the exhaust gas is only at about 100 degrees Fahrenheit, it can be vented with a less expensive venting material, compared to units without condensing technology – which helps you save on installation and venting costs.

Customer Support And Warranties

Beyond special features and overall quality of units, we’ve looked at the quality of customer support available for each unit, and from each brand. We’ve talked with customer service representatives, browsed FAQ and help sections, perused installation and repair manuals, and made an effort to understand the level of support offered by each unit, and the manufacturer.

In addition, we’ve made an effort to note information about warranty coverage, and take this into account when writing our water heater reviews – including information about product registration for warranties, requirements for warranty service, potential deductibles, length of warranty and more.

Diverse Flow Rates

Bigger is not always better. If you have a large family or tend to run a lot of appliances at once, you may be better off with a large, 10 GPM tankless water heater, which can provide up to 10 gallons of properly-heated water per minute.

But if you have a smaller family, or are more economic with your water use, you may be better served by a smaller, 4-6 GPM unit. We’ve made it a point to write water heater reviews about units of every size – so that you can find the right one for you, no matter the size of your home.

Buying Guide

Today, tankless water heaters are gaining popularity, replacing the traditional water heaters. For decades tankless water heaters have been popular in Europe only. But now they are gaining popularity in the US and across the globe. But a great tankless water heater doesn’t come easy. Luckily, we are here to help.

Below, we present with a comprehensive tankless water buying guide. What are the critical factors to consider when buying a tankless water heater? You must be eager to get answers, right? Let’s get to business.

Factors to consider when buying a tankless water heater

First, is purchasing a tankless water heater worthwhile?

Yes! There are enough reasons why you should be considering acquiring one.

Here are some of the reasons why we recommend tankless water heaters:

Longer service life

Tankless water heaters will serve you longer compared to traditional water heaters. Additionally, traditional heaters need a lot of maintenance. On top of that their lifespan is lower.

The tankless water heaters give you value for every penny you spend. That’s not all they are convenient and classy. With proper maintenance, tankless water heaters can serve you for more than 20 years.

Compact design just like furniture

Thanks to the sleek and compact design, these tanks take less space and do not make your attic cluttered.

They give you enough room space. Additionally, cleaning and maintaining the tankless water heater is easier. That’s not all; the design makes them look good.

They are Eco-friendly

Tankless water heaters are environmentally friendly, as they don’t emit any poisonous gas. This is a great benefit. Throughout the world, such technology is being advocated. So if you are looking forward to a cleaner environment, you can start with this tank

They are repairable

For tankless water tanks, spare parts are easily available. This takes away the worries in case the tank develops complications.

On top of that most of them come with a warranty to serve you in the case of any breakdown. Unlike the traditional water heaters, which require full replacement in the event of failure, these are easy to repair.

Low on operating costs

Say bye-bye to huge electric bills every month. This is one of the most significant benefits of these heaters. They heat water on demand, unlike the traditional heaters, which heat water on standby.

Unlimited supply of hot freshwater

Since the hot water is never sitting on the storage tank that guarantees you clean, warm water. This is without the risk of being exposed to mineral scale water or the worst rust water from the tanks.

The hot water flow does not depend on the storage tanks. Therefore, you can take the long slow shower and never run out of hot water.

What type do you need?

When shopping for a tankless water heater, the first decision will be to decide the type. Here you have two options to pick from, tankless and gas-fueled type.

Despite serving the same purpose, there are some differences between them. Some of the differences include price, efficiency, and operations.

In this article, we go through the critical factors to consider when shopping.


They are a bit expensive than the electric type. One thing to note about gas-fueled is that they operate at a low cost and are great in energy saving.

This is one of the reasons why most people prefer them. They also need proper servicing once a year for efficiency and durability. These tankless water heaters are the best choice if you have access to propane or natural gas.

For these heaters to work well, there are some requirements. For example, the fuel supply line must be of an appropriate size. This way, it will provide enough energy to run the large burners needed for heating the water.

Another major concern of the gas-fuelled tankless water heaters is the venting.

Venting helps in the removal of the excess heat emitted by the water heaters. Luckily, they come with vents that can run through the wall or the roof.

The vent’s material is stainless steel that is rust resistant and durable. If you are ready to incur a little more, go for a unit with a condensing unit.

If you decide to get an outdoor tankless water heater, then you do not need to incur the extra cost for venting. This is because the water heater will cool by itself.


Compared with gas-fueled heaters, the electric type is less expensive to install.

But a major downside to their energy consumption. Most of the time, they come in an impressively sleek and more straightforward design. This also makes it easy to repair and troubleshoot.

A bonus point to them is that they need minimal maintenance and can go for a few years without any checking.

There is no requirement for venting in a tankless water heater. In this type no release of exhaust gasses. This makes them eco-friendly since there is no emission of greenhouse gasses.

An added advantage to it is that you can install them anywhere since no venting.

What size do I need?

When people buy a tankless water heater, the question they most ask about size.

What size is best for my house?

Is there an advantage for a smaller heater than a larger one?

Having a small heater that will not serve your household can be very frustrating.

Getting the correct size of a tankless water heater depends on a few factors and key features in your home

Number of usable bathrooms in a house

It is essential to know the number of bathrooms in your home and the frequently used bathrooms.

For example, if you live alone in a house with several bathrooms. Then ask yourself how many bathrooms do you use? Then apart from having a smaller heater, use only one bathroom.

If you live in a big family house, then having a larger tankless water heater could be the right decision.

Additionally, think of the future, do you think you will need a bigger tank?

Depending on these factors you can make the best decision about the size. So use your home size, how many bathrooms you intend to use and the size of your family.

Will you use the heater to multitask?

For some people, they install several water heaters for different tasks in the house. For example, some people place a small tankless water heater for use in the kitchen and another one for use in the bathrooms. Despite this being expensive, it is convenient.

Other homeowners opt to use only one tank for the whole house. In this case, one will need a large size to supply enough water for use in the entire home.

Here you should decide the option to go for, either several small tanks or one large tank. Take time and assess the cost and convenience.

Where do you live?

The question here is where do you live? And how is the climate? Your area’s climate determines the inherent water’s temperature. If you live in a cold area, water temperatures will be lower.

Knowing the incoming water’s temperature is crucial. This is because these heaters don’t heat water to absolute temperature. This, in the end, will mean that you need to get a proper sized tankless water heater to meet your demands.

How many do I need?

This is another critical decision you’ll have to make. As mentioned, think about the size of your house and your water heating demands.

If you want several tanks, then go for smaller ones. But if you opt for one tank, then pick a large one. But is always good to assess the merits and demerits of a larger tank.

Keep in mind that the higher the demand for hot water, the more powerful the water heating system should be. We advise our readers to go for a single, ultra-powerful tankless water heater. This way, you will evade high installation, maintenance, and monthly power bills.


Knowing how long your tankless water heater warranty lasts is a primary concern. Most times, the offered warranty on a product reflects its quality and performance. An extended and straightforward warranty is the best assurance you can get. So, it’s critical to compare the warranty plans for the top ranking units before stating your final pick.

Go for a tankless water heater whose manufacturer backs the heat exchanger(s) for 10-15 years. Most importantly, the manufacturer should provide at least a 1-year labor warranty.

Energy savings/efficiency

Energy conservation is the main reason to shift to this new technology. So, anything that will help you achieve this is not worth it. Therefore, pay close details to all the options. This enables you to find out your best choice. Getting a tank that will help you save on the extra dollars should be of fundamental purpose. However, you wouldn’t want to end up with a water heater that is no different from your traditional water heater.


No one wants to buy a tank today and then replace it tomorrow. One of the greatest determinants of durability is material. Premium quality materials should be rust resistant to keep the water uncontaminated and fresh. On top of that, they should be durable and serve you for long enough with less maintenance.

Fuel type

Selecting the right kind of water heater you want should be at the top of your concern list. Choosing a gas fuelled tank means less operating costs but a bit high maintenance cost. Something else is the installation of the vents for air circulation. Selecting an electric type will reduce your maintenance and service cost, however, an increase in operating costs. One should choose the best type of tankless water heaters that serve their needs and style.

The hot water flow rate

Find a tankless water heater that provides hot water at high flow rates when running multiple appliances. Take an example of when you want the dishwasher running. The laundry was done, and someone else needs to get a good bath soak. All this won’t be possible if your water heater does support high hot water flow rates while serving multiple application points concurrently. You might end up getting lukewarm water instead. Therefore, it’s critical to consider purchasing a tankless water heater with a high flow rate rating.


With the current economic constraints, the price should always be a priority but not a primary selection factor. Ensure that you purchase a tankless water heater whose price is in line with your budget. However, at times, the cost could be dismaying. Avoid the lowly priced, inferior-quality tankless water heaters. By buying an inferior quality tankless water heater, you risk accidents, poor performance, among other undesirable experiences. Go for a decent product whose price lies within your budget.


Buying a great tankless water heater does not have to be a dream anymore. You can get your very own tankless water heater at an affordable price.

It’s time that you set out for a shopping spree for the best water heating system. With a high-grade tankless water heater, you can now have that long hot bath without getting hot water limitations.

Did I mention that you can now sleep at ease without worrying about hot water leakage? This is because these tankless water heaters do not require a lot of maintenance and they rarely leak? Get yourself the best tankless water heaters and have a comfortable life with less worry.

All the best!

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