Best Tankless Water Heater for Large Home

Are you in the process of bathroom renovation? Or maybe your family has become bigger so you need more hot water for long showers? Finding the best tankless water heater for a large home might not change your life, but it certainly will change your bathroom experience.

If you live in a house bigger than 2,322 sq. ft. we could say that you are living in a large home according to American standards.

While most of us have grown up having heaters with tanks, there are certainly many advantages to using tankless ones, especially if you have a huge property with many faucets.

There is a reason why so many homeowners are switching to tankless water heaters. Still, when you have a large home, you might be concerned about a water heater without tank heating all the water you might need.

While this type of unit is always a good choice, we’ve picked 3 products that could hold the title of the best tankless water heater for a large home. 

What Is the Best Tankless Water Heater for Large Home Today?


We’ve listed three different products, all of which can beat most competition when it comes to features and functionality.

1. Overall Pick

Rinnai RL94IN Tankless Hot Water Heater,...
  • Original Design: Tankless hot water heater's...
  • Never Run Out of Hot Water with this Compact...
  • Smart, Durable Design: Includes 12-, 5-, and...
Key Features Pros Cons
Max flow rate 9.8 GPM Great flow rate Not as energy efficient as some other options
Gas Water Heater Instant water heating
Wi-Fi Monitoring Long warranty
Indoor Installation Space-efficient


If you’re looking for the best tankless water heater for large home and you’re considering the best value for the price, you should definitely check this product out. This is one of the best units currently on the market.

It has a flow rate of 9.8GPM and it can help provide water for up to six fixtures. This should be more than enough for most homes out there. Both you and your housemates can get a shower at the same time without disrupting the hot water flow.

Thanks to the Circ-Logic technology it can provide you with hot water almost instantly. You no longer have to wait for the water to warm up. Also, the Wi-Fi monitoring options allow you to schedule the water heating, making everything even faster.

Unfortunately, as this is a non-condensing unit, it isn’t as energy efficient as we’d like, with its energy efficiency ratings being only 81-82%.

As with most Rinnai units, this heater has an amazing warranty. It has a 12-, 5-, and 1-year residential warranty for heat exchanger, parts, and labor respectively. It also has a 1-year commercial factory warranty.

2. Premium Option

Rinnai RU199iN Condensing Tankless Hot...
  • Endless Hot Water: Our tankless hot water...
  • Energy and Space Efficient: The tankless...
  • Optimal Water Pressure: With a hot water flow...


Key Features Pros Cons
Max flow rate 11 GPM
  • Easy to install
Recirculation pump and Wi-Fi unit are additional items
Wi-Fi monitoring
  • Energy-efficient
Gas Water Heater
  • Compact
  • Great warranty


While choosing between Rinnai RU and RUR models can be a challenge, we have found that this RU model can certainly be considered the best tankless water heater for large home. The RU199iN model has amazing features, including an excellent flow rate of 11 GPM. This should be enough for even the largest properties, as it can provide water for up to 7 different fixtures!

Thanks to its Circ-Logic technology and an external pump, it is capable of delivering hot water almost instantly. You no longer need to wait for the water to heat – you can get it in less than a second!

Despite working on natural gas, it has an excellent efficiency rating of 93-96%, as well as the Energy Star certification.

While a bit on the costly side, the amazing warranty helps make up for it. You’ll have a 15-year warranty on heat exchanger, 5-year warranty on labor, and 1-year warranty on parts.


3. Best Price Pick

Stiebel Eltron Tankless Heater –...
  • On-demand, continuous and unlimited supply of...
  • Sleek design saves space and no venting...
  • Electronic switch activated for virtually...
Key Features Pros Cons
Max flow rate 7.5 GPM Space-saving design Not compatible with all types of water fixtures
Electric water heater Energy-efficient
Advanced Flow Control feature Digital display
Large digital display that shows savings Silent


If gas water heaters are not your thing, you can look into this affordable electric unit. While not as efficient as gas water heaters, Stiebel Eltron Tempra 36 Plus has a great max flow rate of 7.5 GPM, making it a good choice for a large home.

It has a copper sheathed heating element that provides you with unlimited supply of warm water almost instantly. At the same, it has an amazing energy-efficiency rating of 99%, making it the most efficient unit out of all on our list!

You don’t have to worry about installing this unit in almost any part of your home, as it has a very silent operation. This is something you cannot achieve with most standard gas heaters.

Its sleek design is a great choice for bathrooms of any size. Just keep in mind that it might not fit all fixtures, at least not without modifications from a professional.

This unit comes with a 7-year leakage warranty, as well as 3-year complete warranty on parts.

Related: Will a Gas Water Heater Work Without Electricity

How We Choose the Best Tankless Water Heater for Large Home


When looking for the best tankless water heater for large home, there are many things you need to consider. You don’t want to just spend money on the first unit you’ve found!

Instead, you might want to look a bit into the features of a product you’re interested in.

Sure, depending on your demands and desires, there are many features you would consider essential. Still, there are a few things everyone should look into before they make their purchase.

Here are some of them:


When choosing the best tankless water heater for large home, likely the most important feature you’re worrying about is its size. To determine the right size of the water heater, there are two things you need to ask yourself:

  1. What are the maximum hot water needs in your home?
  2. How much GPM can the water heater you’re interested in heat up, and to what temperature?

* GPM – gallons per minute – standard rate for American home is around 1.5 – 3 GPM [source]

To determine this, you need to think about how many water sources you plan to keep on at the same time. The busiest hours for this are usually late evenings, when most families go to shower. This is an estimation of how much water every fixture requires:

  • A shower will require 2.0 to 3.0 GPM.
  • A faucet requires 1.0 to 2.0 GPM.
  • A standard dishwasher requires 1.5 to 2.0 GPM.
  • Most washing machines require 2.0 to 2.5 GPM.

If you usually use one faucet and one shower simultaneously, you’ll likely require a tankless water heater that has at least 5 GPM. However, if you usually have a washing machine on at the same time, you’ll need a larger one.

Fortunately, most tankless water heaters can deliver up to 12 GPM of hot water. 5 to 10 GPM is usually required for most typical households, but for larger homes we normally recommend at least 7 to 10 GPM, just to be on the safe side.


Unit Type

Today, there are many types of tankless water heaters, such as:

You need to find the one that will accommodate your needs. For example, choosing the best tankless water heater with recirculating pump might be the great option for homeowners looking to save more energy.

Fuel Type

Another thing you need to think about is the type of fuel your unit will use. There are two types of units based on the fuel they use:

  • Electric tankless water heaters that tend to be smaller and cheaper units. They are a great option if you’re choosing to install your heater on pre-existing piping, as they are more flexible.
  • Gas tankless water heaters run on liquid propane or natural gas. They tend to be quicker and more energy efficient than electric units, but they are costlier and require expensive installation.

In general, gas water heaters tend to be better for larger homes, but it all comes down to the specific unit you plan on buying.


When calculating the price of a tankless water heater, there are two things you need to consider:

  • The initial purchase price.
  • The installation price.

All tankless water heaters require professional installation. As such, the initial price isn’t the only money you’ll have to pay.

While it might not be smart to purchase the most affordable unit out there, you shouldn’t let the price determine the quality. Instead, always look for the best value for the price.

Why Go Tankless?

No unit is perfect. This includes both water heaters with tanks and tankless products. Even tankless water heaters are known for their pros and cons. However, there are some reasons why you should seriously consider going tankless.

Tankless water heaters have many pros, especially if you live in a large property or if your family is large. Here are some of them:

Endless Hot Water Supply

When you have a water heater with a tank, you’re limited with the amount of hot water you can use. Tanks have a certain capacity. Once the capacity is depleted, you will no longer have hot water until the tanks heats it up again. This can become a huge problem if there are more people in need of a shower.

However, when you have tankless water heaters, you’re no longer limited by a tank. Instead you’ll have a nearly endless supply of hot water. This means that all family members can take a shower one by one, and you still won’t run out of hot water.

If you have a large family, this is likely the main reason why you’d like to switch to tankless water heaters.

Fresh Water

Water heaters with tanks store water until you use it. This can take a while. This means you won’t get fresh water but rather one that was sitting for hours, maybe even days if you’ve just come back from a vacation or some long trip.

There are many reasons why you don’t want this. First and foremost, tanks can be filled with lime scale and mineral buildup. Rust is also common, and there are many harms in drinking rusty water. This can even lead to bacterial infections.

When you deal with tankless water heaters, you’ll always have fresh water. This lowers the chances of contamination, making it a much healthier choice for your whole family.

Energy Efficiency

Compared to water heaters with tanks, tankless water heaters are much more energy-efficient. In fact, according to the US Department of Energy, they can help you save up to 34% more energy than standard units.

One of the reasons behind this is that they heat up water on demand. Water heaters with tanks will heat up a certain amount of water. If you don’t spend it all, the water will cool down, which means the heater has wasted all the energy on heating it up for nothing. As tankless heaters heat up water instantly, they’ll only heat the amount you need.

As such, even though the initial purchase and installation costs are fairly high, you’ll probably end up spending less money than you would with a standard water heater, especially in the long run.

Longer Lifespan

Another reason why the initial high price of tankless water heaters shouldn’t worry you is their long lifespan. It isn’t uncommon of them to last more than 20 years! If you keep in mind that most regular water heaters have a lifespan of 10 to 15 years, it’s easy to see the advantage tankless heaters have.

One of the reasons behind this is due to their many replaceable parts. For example, if you notice your regular water heater leaking at relief valve or any other part, you might have to replace your entire unit.

On the other hand, most tankless water heaters are made with parts that are entirely replaceable. If some part breaks, you can simply swap it with a new one.

Not just that, but one of the main reasons why water heaters break down is precisely the tank. As tankless water heaters don’t have tanks, this is one less problem to worry about.

Read Next: Rinnai vs Navien

The Bottom Line

So, what is the best tankless water heater for large home? It can be challenging to pick a single unit due to many excellent products and different needs all buyers have. When you want a water heater that will work for your large property, you will need to be even more careful when choosing a reliable unit.

Still, we are certain you won’t make a mistake with any of the units we’ve listed. Of course, there are many more great tankless water heaters out there, so you can feel free to use our guide and find the product that suits your requirements.

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