7 Best Tankless Water Heater for 3 Bathrooms Reviews

Standing outside the bathrooms and waiting for your turn on taking a bath on a busy morning can really be an annoying thing, especially when there are multiple family members in eager of using bathrooms at the same time. Thus, you may consider installing a large capacity tankless water heater that supports 3 bathrooms use simultaneously.

Getting the best tankless water heater for 3 bathrooms to use require not only the large capacity but also excellent performance in offering stable water flow. But what else?

Well, this post is here to give you the expert guidance on how to choose the best type for multiple rooms to use, and if you find it a waste of time selecting by your own, we have picked out top 7 models on the market of 2020 that you can choose directly.

Now, let’s begin!

What Is the Best Tankless Water Heater For 3 Bathrooms?

7 Best Tankless Water Heaters for 3 Bathrooms

How to Choose the Best Tankless Water Heater for 3 Bathrooms?

There are dozens of tankless water heaters for three bathrooms different in sizes and models, making it tricky to choose your home best. Here are some of the factors to consider before making your final choice.

Fuel type

One of the vital considerations when finding the best tankless water heater for 3 bathrooms is determining the fuel type you require. A tankless water heater can be powered either by electricity or natural gas. If you opt for an electric tankless water heater for your bathrooms, ensure you have a proper voltage outlet, a separate circuit to plug the heater, and your home has sufficient amperage draw to support the water heater.

If you need a heater powered by natural gas, ensure that you have enough gas supply line to support the water heater. Also, ensure that you have adequate venting for the gas tankless water heater for three bathrooms. It might force you to retrofit your home.

Flow Rate (GPM)

A tankless water heater’s flow rate is one of the vital factors to consider when finding your bathrooms’ ideal heater. The flow rate determines the volume of hot water; the heating system can produce and is measurable in gallons per minute (GPM). Luckily, there are various tankless water heaters capable of supporting two or more outlets to run simultaneously. For a tankless water heater for three bathrooms, consider one with a 7.5 to 8 GPM flow rate. They also ought to be larger and more potent to supply hot water when needed in the three bathrooms sufficiently.

Energy Efficiency

One of the main benefits of using a tankless water heater is energy efficiency. Therefore it is essential to consider the amount of utility cost you will save when you purchase the model you need. You should check the product Energy Efficiency (EF) before buying the heater to determine its overall efficiency. Select a tankless water heater for three bathrooms with a high EF rating because a higher rating implies it is more energy-efficient.


Tankless water heaters come in different sizes ranging from small to large. The space you want to install the unit will influence the size of the heater you will buy. Therefore before purchasing your heater unit, you should first measure the space you want to install and select a corresponding size.

Also, the capacity you require will determine the ideal size of the heater you will need. The higher the volume, the more apparent the size. Choose a tankless water heater for 3 bathrooms with a capacity that will sufficiently supply hot water and fit in the planned installation space.

Temperature rise

Another essential factor to consider when selecting the best tankless water heater for 3 bathrooms is it’s the capability of heating water to the required temperatures. In determining the tankless water heater’s temperature rise capabilities, it requires the incoming water temperature in your home. In colder climates, consider buying a unit with a higher temperature rise capability. But in warmer climates, a less powerful heater will be ideal. To know the incoming water temperature in your home, you can check out in online heat maps.

Best Tankless Water Heater for 3 Bathrooms Review

1. Best Natural Gas Indoor Heater – Takagi T-KJr2-IN-NG

best electric tankless water heater for large homes


Powered by natural gas, this unit ranks at the top of powerful and high energy efficient heaters on the market. Maximum flow rate reaches 6.6GPM, in warm weathers, it feeds up to 3 or even 4 bathrooms use at the same time.

Look strong and heavy; it is actually pretty light and small. The moment you open up the box, you are stunned of how much room is not being occupied! Stainless steel inlet and outlet prolongs its service life.

It requires indoor installation, and the process of it is a bit hard. You may choose expert installation by digging out more money from the wallet. The downside of DIY is the loss of warranty, but if you are a handyman, this really saves much money.

2. Best Residential Electric Heater for Small Home – Rheem RTEX -18 best tankless water heater for large family


The electric instant water heater has always been regarded as a less powerful type, compared with a gas one, yes, it is the truth. However, among other electric heaters, this unit is really worth recommending on providing hot water for 3 bathrooms use.

The maximum flow rate of it is 4.4GPM, with the self-modulation system, it reduces the using costs by adjusting power automatically, which means it heats water only when you need it.

LCD temperature control panel displays not only the current water temperature but also some error codes, in remind of fault operation. No clicky noise, no leakage, and no working noise. What left is a satisfying user feeling.

3. Best Commercial Tankless Water Heater – Rinnai RUC98iN Ultra Series Natural Gas Heater


best tankless water heater for 3 bathrooms

Works as a commercial tankless water heater, it handles 3 bathrooms use at ease. Double pipe offers you binary options on venting, either concentric or PVC. It features best in energy saving. Condensing technology improves the energy factor to 0.96, which means less energy is lost in the process.

In the middle part of the heater set a control panel, for adjusting water temperature and power. If you use it commercially, you may purchase a separate commercial controller.

The water stays at a stable and constant temperature, even when there are multiple water sources use at the same time. Entire working process is also quiet and smooth, with unlimited hot water at hand.

4. Best Condensing Tankless Water Heater – Takagi T-H3-DV-N High-Efficiency Natural Gas Heater

best tankless water heater for family of 6


More of a heater for 3 bathrooms, this unit is worth praising as a best tankless water heater for family of 6. Why? Well, it is a commercial standard heater, the water capacity ranks the largest on the market, reaching up to 10 gallons.

Will it waste a lot of money on energy costs? No, it is a condensing type; it improves efficiency with a secondary heat exchanger. The installation is fairly straightforward and requires no venting facilities, but only PVC.

Even in cold weathers, it is suitable for multiple bathrooms to use, for it provides 199,000 BTU gas input in using. Large in power, it is quite compact and small, perfect for installing somewhere small and narrow.

5. Best Propane Tankless Water Heater for 3 Bathrooms – Rheem RTG – 95DVLP – 1 Direct Vent

best tankless water heater large family


Another Rheem heater, but is a propane type, which is more powerful than electric model but is also not as expensive as natural gas one. You may install it indoor or outdoor; it requires a direct vent. The low NOx design protects the environment greatly.

With an optional control board, you can manifold it up to 6 units, serves well for commercial use. The installation is simple and direct, but we still recommend an expert to help to install for you.

With a 120V power cord, you will get constant hot water with a stable temperature, perfect for 2-3 bathrooms homes.

6. Best 6.6GPM Natural Gas Water Heater – Noritz NRC66DVNG Indoor Condensing

best tankless water heater for one bathroom


The maximum flow rate of it is 6.5 gallons per minute, which delivers the highest one among its categories. With the fully-condensing design, it narrows the using costs and energy costs to a large extent.

Double venting options allow you to choose a simple PVC venting instead of stainless steel type. Though it uses natural gas as a major power, you still need electricity as ignition. The sound of ignition can hardly be heard from anywhere in the house, and it keeps as quiet during the whole using time.

It takes little time to heat up, and once hot water flows out of the pipe, the temperature of it keeps stable, which means no cold water sandwich occurs.

7. Best Energy Star Tankless Water Heater – Rinnai V65IN 6.6 GPM

best tankless water heater for family of 4


Compared with most large capacity tankless water heater, this one is a lot cheaper and affordable. 0.82 maximum energy factor also works for reducing energy and using costs. The small footprint allows more room for other accessories like a water softener installed.

Being an energy star heater, the temperature setting of it ranges from 98F to 140F. The leak detection shuts off the heater as to lessen the possibility of damage to the unit.

Durable as it is, you will find it highly quiet in working, with only the sound of water flow. Plus, you need only wait for several seconds before hot water flows out. Anyway, a highly recommended type for a tight budget!



What Types of Heaters Are Suitable for 3 Bathrooms to Use at the Same Time?

Four main types of heaters can conveniently supply hot water for 3 bathrooms, even when in use at the same time. Each type has its benefits and drawbacks. Below is a description of each water heater to guide you to choose one that is the best for your home.

Conventional storage water heater

This water heating system is the most popular in many homes. It features a tank holding water for heating. The capacity of the tank influences the volume of hot water you have available at once. Therefore, you will need a storage tank with a larger capacity for you to get water at three bathrooms at once.

This tank features a pressure control valve and a temperature control valve. It is also insulated to maintain water hot when it heats up. This water heater system is generally the most affordable and easy to install. Some of its drawbacks are that after completing heated water, the refilling and reheating process takes time. Also, there is energy wasted through standby heat loss.

Tankless water heaters

This water heating system features modern technology and provides an instant hot water on-demand basis. When cold water enters the heater, it instantly heats by an electric element or gas heater. These units are available in different sizes, and therefore you will need to select an ideal size that can sufficiently supply hot water to the three bathrooms at once.

The benefit of this style is that it is energy efficient as it heats water on demand. The downside of a tankless water heater is that the initial investment needed to purchase and install this unit’s necessities is significantly higher than traditional styles.

Heat pump water heater

You can also use this heater in three bathrooms at the same time. This heating system is energy-efficient and cost-effective as they use electricity only in moving heat. This water heater uses heat in the air in heating water. This water heater style’s major drawback is that it cannot work well in cold spaces or areas with a frigid climate for more extended periods.

Solar water heater

Another heater that is suitable for three bathrooms use at once is a solar heater. This heating system uses roof-mounted solar panels in heating water.

Solar water heaters are energy-efficient and environmentally friendly. They work quite well during sunny seasons and in hot areas. However, to install the solar panels is quite expensive and can take long before you get value for your money. The heating system is also not ideal in cold weather, and you may need an alternative source of power.

Best Tankless Water Heater For 3 Bathrooms Prices

Different tankless water heaters are available in a wide range of prices. The average cost of buying the best tankless water heater for three bathrooms ranges from $1000-3000 and even more. The cost of these units depends on several factors, including.

The brand

There are many manufacturers of tankless water heaters in the market. Different brands charge different prices on these units, depending on the manufacturing cost involved.

Some of the popular brands are Eco smart, Rheem, Rinnai, among others. When choosing the best tankless water heater for your bathrooms, regardless of the cost, consider a brand with a review of having fewer product issues and the one that offers a convenient warranty. This review will guarantee you will get value for your money even if you pay a higher price.

Gas vs. electric tankless water heater

Another influencing factor to these units’ prices is power. The cost of purchasing a gas tankless water heater is way up to higher than that of an electric.

However, in the long run, a gas heater is more cost-effective than the electric tankless heater. Therefore, if you plan to stay in your home for long periods, have larger water demands, and you can bear the initial and installation cost involved with a gas tankless water heater, it is the best option.

If your home has less water demand and you don’t intend to stay for longer durations in the house, you can consider an electric tankless water heater for bathrooms.


Another aspect that influences the tankless water heater’s price is the feature a unit has. The more features a heater has, the higher the cost. Some tankless water heaters are more energy-efficient, and other digital connectivity attributes enable you to adjust the temperature using your phone. When selecting the best tankless water heater for 3 bathrooms, consider one with more features to bring along convenience in the unit’s operations.

The Final Verdict

A best tankless water heater for 3 bathrooms use should be capable enough on providing stable and constant hot water; however, purchasing the most recommended one is not always true. What you need is the most suitable unit for your demand; in other words, always take your demands and budgets into consideration in purchasing!


There are many other types available for other using situations; you may check for them also.


David: Penn State-educated Mechanical Engineer and Business-savvy Fluid Dynamics Specialist. Balances family plumbing business support with a thriving engineering career at a top, undisclosed company. (they want it that way) I help Will with plumbing and HVAC needs on his Real Estate.

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