Best Tankless Water Heaters For On-Demand Hot Water

Gary Johnson
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Tankless water heaters provide a continuous supply of hot water at the ready.

Any home that desires a continuous supply of hot water during peak demand times will benefit from installing a tankless water heater.

The most common complaint about the tankless water heaters is the initial installation costs, which are usually associated with the size of the unit.

Tankless water heaters are long-term investments in your home improvements. This is especially true if you install a tankless system to help reduce your energy bills.

There are many brands of tankless heaters out there to choose from, here are some nice ones for you to consider.

Although it might not seem important to do a home improvement project on a tankless water heater, you will benefit immensely from doing so.

NameCategoryProduct
Stiebel Eltron Tankless Water HeaterBest OverallStiebel Eltron Tankless Water Heater
Ecosmart ECO 36 36kw 240V Electric Tankless Water HeaterBudget PickEcosmart ECO 36 36kw 240V Electric Tankless Water Heater
Rheem RTGH-95DVLN 9.5 GPM Indoor Direct Vent Tankless Natural Gas Water HeaterUpgrade PickRheem RTGH-95DVLN 9.5 GPM Indoor Direct Vent Tankless Natural Gas Water Heater

1. Stiebel Eltron Tankless Water Heater

Our rating: 9 / 10

Stiebel Eltron Tankless Water Heater

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Pros:

  • Budget-friendly
  • High capacity
  • User-friendly features
  • Installation is straightforward
  • High reliability

Cons:

  • Expensive electric bills
  • Must have 220V wiring
  • Not suitable for outdoor use
  • Interface could be more intuitive
  • Water temperatures are lower than those of tank heaters

The Stiebel Eltron Tempra 24 Plus is our top pick for tankless water heaters. With its hot-water-ready indicator and ease of use, the Stiebel Eltron is a great water heater for any household. Its impressive ability to deliver consistent hot water on-demand also makes it a perfect choice for those looking to upgrade to tankless.

The Stiebel is simple to install, so if you can’t do it yourself, have it installed professionally. The Tempra also comes with a 15-year warranty on parts and labor.

One issue you might encounter with the Stiebel, however, is the high electricity bill you’ll have to pay due to it being an electric water heater. The reason for this is that your electrical usage will be close to double (or even triple) the amount after you install an electric water heater.

2. Rinnai RUC98iN Ultra Series Indoor Natural Gas Tankless Water Heater

Our rating: 9 / 10

Rinnai RUC98iN Ultra Series Indoor Natural Gas Tankless Water Heater

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Pros:

  • No storage tank – ideal for homes where tankless water heaters already exist
  • Highest BTU rating of Rinnai’s current tankless water heater model
  • Safe to use with any natural gas line
  • Safe to install outdoors (IPX5 standard rating)
  • Safer than electric tankless water heaters
  • 30% more energy efficient than standard tank water heaters
  • No generator necessary – ideal for houses without wiring for backup electric water heaters
  • Quick-scan dial – easy to set and view water temperature

Cons:

  • Since it doesn’t have a storage tank, its pilot light will remain hot, and it won’t turn off automatically
  • Due to the high energy consumption, this option is a bit more expensive as compared to other water heaters
  • 30- and 50-gallon models not available
  • Can be somewhat loud, especially if you set the temperature very high.

98,000 BTU.

3. Ecosmart ECO 36 36kw 240V Electric Tankless Water Heater

Our rating: 7 / 10

Ecosmart ECO 36 36kw 240V Electric Tankless Water Heater

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Pros:

  • Can deliver hot water fast and efficiently
  • Simple design
  • Cost-effective to operate

Cons:

  • Does not come with an installation kit, so you need to purchase that separately
  • Only suitable for home and commercial use with a 240V electrical outlet, though there are models available for 120V too
  • Requires a company electrician to install it

For many homeowners, electricity bills account for a large majority of their utility bill, with heating water being at the top of the list. If your home’s hot water tank is sitting idle for long periods of time when you don’t have enough water for your shower, washing dishes, doing laundry, etc., you could be losing a lot of money in wasted electricity.

Fortunately, technology has found a way to give you on-demand hot water without having to wait for it to heat the tank. With an electric tankless water heater, you get a continuous supply of hot water for showers, dishes, and laundry, all while saving you energy and money on your electricity bills.

4. Takagi T-K4-OS-NG Tankless Water Heater

Our rating: 6 / 10

Takagi T-K4-OS-NG Tankless Water Heater

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Pros:

  • Highly energy-efficient
  • Safe to use with the highest levels of water quality
  • Environmentally-friendly natural gas heater
  • High-quality construction with sleek design
  • Has low emissions and low noise levels
  • Safer than traditional tank water heaters
  • High BTU compared to other brands, ideal for homes with more than 4 bathrooms

5. Rheem RTGH-95DVLN 9.5 GPM Indoor Direct Vent Tankless Natural Gas Water Heater

Our rating: 6 / 10

Rheem RTGH-95DVLN 9.5 GPM Indoor Direct Vent Tankless Natural Gas Water Heater

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Pros:

  • Best in class heat exchanger
  • High capacity
  • Great for cold climates
  • Easy-to-reach service valve
  • Quick installation and start-up

The Rheem RTGH-95DVLN is our top pick for best tankless water heater for several reasons, namely heat exchanger size, high capacity, and great performance, even in cold climates.

The Rheem RTGH-95DVLN has a 95% efficient heat exchanger. This allows the water heater to run exceptionally fast and deliver an impressive 9.5 gallons per minute (2.6 gallons per second), which is necessary for a fast-paced shower.

What’s more, the size of the heat exchanger is designed to last for a very long time. At 1.3 times more efficient than conventional water heaters, this efficient heat exchanger avoids wastage and reduces the operating cost.

6. Takagi T-KJr2-IN-NG Indoor Tankless Water Heater

Our rating: 6 / 10

Takagi T-KJr2-IN-NG Indoor Tankless Water Heater

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Pros:

  • Safe to use
  • Quick installation
  • Compact size
  • Economical and environmentally friendly
  • Energy star qualified
  • Comes with 4-year limited warranty

Cons:

  • Unwieldy digital display
  • Silicone coating the tank’s surface is prone to chipping
  • Average flow rate

120V, 3,800W, 125-psi Maximum Pressure, and 50-psi Minimum Pressure.

If you’re looking for the best tankless water heater in the market, the Takagi T-KJr2-IN-NG is definitely worth a closer look. It’s a natural gas-powered, tankless water heater that will endow you with the convenience of on-demand hot water.

The installation process is incredibly simple thanks to the quick disconnect hose and electrical terminals. It’s also a compact unit, which means you’ll be able to save on space in your kitchen.

7. Eccotemp L10 2.6 GPM Portable Tankless Water Heater

Our rating: 5 / 10

Eccotemp L10 2.6 GPM Portable Tankless Water Heater

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Pros:

  • Super-efficient, meaning you can shower and do dishes at the same time
  • Comes with a 6-year warranty

Cons:

  • Need to have a horizontal water pipe
  • Easy to break if not used properly

We chose the Eccotemp L10 portable tankless water heater for its efficiency and for its affordability. It’s a cost-effective way to have instant hot water, unlike traditional tanked water heaters, which tend to waste water and charge you for it.

If you’ve ever been in a house that had a tanked water heater and gone to take a shower, only to discover that the hot water is all gone, then you know how much of a waste it is. With this unit, you don’t need to worry about running out of hot water. In fact, you can have a hot shower and wash dishes at the same time!

The unit is capable of producing 2.6 gallons of hot water every minute, which is pretty efficient. That said, you should keep in mind that to maintain desired efficiency levels, the unit needs to be installed horizontally between the hot and the cold water tanks. The same goes if you want to hook up the unit to a horizontal outdoor water hose.

8. Sio Green IR30 POU Infrared Electric Tankless Water Heater 120v / 8A

Our rating: 4 / 10

Sio Green IR30 POU Infrared Electric Tankless Water Heater 120v / 8A

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Pros:

  • Quiet operation
  • Very compact (a lot less space than many other models)
  • Only uses 30% more electricity than a standard electric element
  • Removes scale build-up in older tank units
  • Can draw in cool water
  • Does not require HVAC
  • One year warranty

Cons:

  • Costly up front compared to conventional tanked hot water heaters.
  • This unit get really hot, so needs to be installed in a well vented area.
  • Will heat the shower room – not so great in cold weather.

Piped at 5psi.

In summary, the Sio 230V is comparatively expensive, but delivers benefits that will make it worth every extra dollar. It is gaining in popularity and is gaining a reputation for adding real value to life.

Frequently Asked Questions (FAQ)

What is the best on demand hot water heater?

By now you know that an on-demand heat generates water as needed on a continuous basis, which means you are not stuck with a tankful of hot water. By now you have likely also seen that it is not that simple to locate the best on-demand water heater. There are a lot of on-demand heaters available, but just because it is listed for sale on a website doesn't mean it's the appropriate heater for your needs.

One of the first things you should check is the energy efficiency of the on-demand water heater you are interested in. This will benefit your pocketbook and the environment. On-demand heaters are more efficient than tankless heaters, and this to some degree reflects into the price.

What is the downside of a tankless water heater?

Most tankless water heaters have a limitation of about 4-6 gallons of continuous hot water per minute. This means that if you need to take a hot shower and wash the dishes at the same time, a tankless water heater will not be able to handle both those needs. A tankless water heater is also an additional variable when you look at your electric bills so only purchase this type of heater if you really need one.

In summary, tankless water heaters are a great addition to any home but they do have some limitations. They save you money by saving water and there is something satisfying about knowing that your pipes aren’t being used 24-7 to heat water.

Is tankless hot water heater better?

The short answer is yes! Tankless water heaters heat water only when you need and use it. So, it cuts down significantly on the energy you need to use for your hot water heater. The generally can save you as much as 70% of the energy that a traditional tank water heater can use.

Up to 50% of home energy goes to heating water, so being able to avoid heating water you don't need has a major impact on your utility costs, and thus your overall energy usage and your carbon footprint.

Tank water heaters have an internal heating source that works to heat the water as it is stored in the tank. Once the tank is full, the water that is at the bottom stays hot while the water that is drawn first gets cold.

Do tankless water heaters provide unlimited hot water?

Yes, in general a tankless water heater stores as much hot water as a traditional tank and can bring hot water to the fixture as quickly. While a tankless water heater does not have to empty a large tank to provide hot water, it can operate near capacity because it is always filling with hot water being produced.

So every appliance in your home will be getting hot water instantly and you won't have to wait for 30 minutes before taking a shower, umpteen minutes before the washing machine can finish its cycle, or heaven forbid, minutes on the phone to the water company to find out why the water started to act "funny" when you turned on the taps.

Tankless water heaters, such as tankless gas water heaters, are a good investment because it's not so much having control of the water temperature as it is to not have to wait for hot water in the first place.

Conclusion

If you’re an avid reader of product reviews, you’ve probably come across dozens of articles before this one that talk about tankless water heaters. However, there’s a good chance that the amount of information is overwhelming for most of us. And when it comes to making a major decision on such a big investment, you should be certain you’re making an informed decision, instead of just relying on instinct and hoping for the best. That’s why we are here to help you figure out the things you should know before you make a big decision.

Our Recommendation

NameCategoryProduct
Stiebel Eltron Tankless Water HeaterBest OverallStiebel Eltron Tankless Water Heater
Ecosmart ECO 36 36kw 240V Electric Tankless Water HeaterBudget PickEcosmart ECO 36 36kw 240V Electric Tankless Water Heater
Rheem RTGH-95DVLN 9.5 GPM Indoor Direct Vent Tankless Natural Gas Water HeaterUpgrade PickRheem RTGH-95DVLN 9.5 GPM Indoor Direct Vent Tankless Natural Gas Water Heater