Best Tankless Water Heater for Hard Water in 2022 – BestHeaterGuide

If one says that hard water is the biggest nemesis of a tankless water heater, it wouldn’t be wrong. Tankless water heaters have never been fully compatible with hard water. However, it doesn’t mean that a tankless water heater cannot work with hard water. What it means is that your tankless water heater is going to run into trouble frequently if your locality has hard water and you do not take care of it adequately.

Why is hard water such a problem for the tankless water heater?

Hard water is tough on the tankless heater because minerals are left behind in the unit when hard water is heated. These minerals can cause your tankless heat exchanger to become corroded, resulting in decreased efficiency and an increased chance of failure. You can work around this issue by flushing out the accumulated scale from time to time. A tankless water heater with a non-corrosive heat exchanger and anti-corrosion metal parts can withstand hard water in the long term. However, it doesn’t mean that you don’t have to flush your tankless water heater. To lessen the frequency of cleaning your tankless water heater, you can also install a water softening system.

Quick Shopping Tips for Best Tankless Water Heaters for Hard water

Budget pick

EcoSmart ECO 27 is effective against hard water due to its copper heat exchanger. Copper heat exchangers are durable and give the highest thermal efficiency ensuring quick heat-up of water. It also includes a lifetime warranty ensuring ease without any worries.

Best pick

Sio Green SIO 18 is the best pick against hard water as it uses a non-metallic quartz heat exchanger that doesn’t allow the scalp to deposit on heating elements. It also got a self-cleaning design that removes the rest of the sediment from the tankless unit without needing to do maintenance.

Staff pick

Takagi T-H3-DV-NG is a condensing tankless water heater that gives 10 GPM of hot water supply. It uses dual heat exchangers. The primary heat exchanger is made of copper while the secondary one is made of stainless steel. It is the best choice for a large family due to its comparatively low cost and higher flow rate.

At a Glance:

Our recomendation for top 8 Best Tankless Water Heaters for Hard water

Hard water is a word that refers to mineral-rich water, such as calcium and magnesium. Initially, when it rains, the raindrops fall to earth in a sufficiently pure form which we call soft water. It is termed so as currently the water drops are pure from other minerals. However, after the rain, the water gets absorbed in the earth and move underneath the earth’s crust. In its movement, it comes across the minerals present in the earth which dissolve into the water and make it hard water.

Tankless water heaters are less susceptible to the effect of hard water as they operate for the smallest durations based upon your demand. Hence, the scalp accumulation in the tankless water heater is slower compared to the tank water heater.

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Best Electric Tankless Water Heaters for Hard water
Best Pick1. Siogreen SIO 18 tankless water heater
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Best Outdoor Tankless Water Heaters for Hard water
2. Takagi T-KJr2 tankless water heater
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Best Tankless Hot Water Heaters for Hard water
3. Stiebel Eltron Tempra 24 Plus tankless water heater
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Best Budget Tankless Water Heaters for Hard water
Budget Pick4. EcoSmart ECO 27 tankless water heater
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Best 240V Tankless Water Heaters for Hard water
5. Rheem RTEX-24 tankless water heater
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Best Indoor Tankless Water Heaters for Hard water
6. Rheem RTGH-95DVLN-2 tankless water heater
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Best Natural Gas Tankless Water Heaters for Hard water
7. Rinnai RUR199iN tankless water heater
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Best Condensing Tankless Water Heaters for Hard water
Staff Pick8. Takagi T-H3-DV-N tankless water heater
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1. Siogreen SIO 18 tankless water heater

Best Pick

Best Electric Tankless Water Heaters for Hard water

SioGreen SIO 18 tankless water heater
SioGreen SIO 18 tankless water heater

It is probably the best tankless water heater there is for hard water. The reason is that it doesn’t use a metallic heat exchanger but a quartz heat exchanger. Which results in no scale deposit on the heating element. In addition, the heating elements are not in direct contact with the water but use far-infrared energy to heat the water.

It works in such that it uses quartz tubes to act as the heat exchanger, inside of which the far-infrared energy is passed to heat the water. Whereas the outer side of the quartz tubes are coated to contain the far-infrared energy inside, while only letting the heat be transferred into the water. It includes a self-cleaning design that removes any other kind of scale remnant in the tankless unit.

Features

1.         Overheating protection

Overheating protection prevents the tankless unit from heating water above a certain level in order to protect you and the tankless unit.

2.         GPM and Temperature rise

Temperature Rise        30° F   40° F   50° F   60° F

Flow rate         4.0 GPM         3.6 GPM         3.0 GPM         2.5 GPM

3.         Modulation technology:

The latest model of tankless water heaters comes with modulating technology. As who doesn’t like to pay only for what they get. Similarly, an SIO 18 also utilizes modulating technology to make sure that it works at maximum efficiency at all times based on your demand. A modulating technology allows the tankless water heater to modulate its operational activity to meet the required level.

4.         Warranty

SioGreen offer a warranty for the unit purchased and installed in the US. You also need to register a warranty with the manufacturer within 30 days of purchase. Sio 18 comes with 5 years warranty on the unit and an additional five-year warranty on the heat exchanger.

Unit’s requirements

      This module needs the following requirements for proper functioning; 

  • Minimum flow rate demand is 0.5 GPM
  • Water pressure supported between 15-150 psi
  • Voltage demand is 220V
  • Max power demand is 75 Amp
  • Minimum breaker recommended is 80A (2 x 40A)
  • wattage consumption is 18KW
  • Gas and Water connection fittings use 3/4 in. NPT
  • 2 x 8-gauge wiring required

Specifications

  • Color: White
  • Weight: 27 pounds
  • Dimensions: 14 inches in width, 20 inches in height, and 6 in-depth

Pros

  • Corrosion-free
  • Capable of working with hard water
  • Highly Energy Efficient (98%)
  • Maintenance-free

Cons

  • Most of the units are POU hence low hot water output.
  • SIO 18 is the largest unit by the manufacturer.

Why you should buy this?

It is an energy efficient solution to your hot water needs. It also doesn’t let you down when it comes to saving energy, as its 98% Energy Efficient. While its quartz heat exchanger give you a permanent solution to hard water.


2. Takagi T-KJr2 tankless water heater

Best Outdoor Tankless Water Heaters for Hard water

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

If we talk about gas tankless water heaters that give the best value to your investment, one name that you will likely hear will be Takagi T-KJr2. It gives you higher hot water capacity, energy-saving, and several safety features that make it reliable and have a longer lifespan. Such that it can give excellent performance even if your locality has hard water.

Features

1.         Modulation technology:

Takagi T-KJr2 comes with smart technology which allows it to match its operational level with your hot water demand to ensure the highest energy saving as well as the needed hot water.

2.         GPM and Temperature rise

Temperature Rise        35°F    50°F    60°F    80°F    100°F

Flow rate         6.6 GPM         4.7 GPM         3.7 GPM         3 GPM            2.5 GPM

3.         Multiple level protection:

Takagi supports multiple protections in terms of freezing, overheating, and electrical surge.

4.         Troubleshooting error codes:

Let you know what problem your tankless water heater is facing.

5.         low NOx:

Its eco-friend design allows you a lower emission of NOx.

6.         Warranty:

The warranty of Takagi T-KJr2 comes with the implied condition of professional installation hence a D-I-Y installation will void the warranty. In the case of professional installation, it comes with a five-year warranty on Part replacements and a ten-year warranty on the heat exchangers.

Certifications

Certified by UL 499 and Energy Star.

Unit’s requirements

      This module needs the following requirements for proper functioning; 

  • Activation Flow rate demands is 0.50 GPM
  • Support Water pressure between 30-150 psi
  • Voltage demand is 120V
  • Water & Gas connection compatible with ¾ in. NPT fittings
  • Venting supports stainless-steel direct venting (4 inches)
  • Minimum and Maximum BTU demand is 19500 and 140000 BTU

Specifications

  • Color:White
  • Weight: 38 pounds
  • Dimensions: 6.7 inches in depth, 13.8 inches in width, and 20.3 in height

Pros

  • Overheating, freeze and surge protection
  • Low NOx
  • Energy Star Certified
  • Troubleshooting Error codes help in problem diagnosis
  • Superior warranty

Cons

  • Energy efficiency of 82%

Why you should buy this?

If you are looking for an option that will give you long-term value to your investment, then Takagi T-KJr2 is the right choice to go with. It provides you high utility value and has multiple safety aspects that can result in having very less maintenance costs. not to mention dealing against hard water.


3. Stiebel Eltron Tempra 24 Plus tankless water heater

Best Tankless Hot Water Heaters for Hard water

Stiebel Eltron Tankless Water Heater
Stiebel Eltron Tankless Water Heater

Stiebel Eltron Tempra 24 plus is an excellent choice for an electric tankless water heater. It is within most people’s budget and can also cope up with the hard water scale deposits. It has solid copper heating elements that make it resistant to scale deposits and corrosion. The copper heating element ensures that the tankless water heater operates at a normal rate and at the highest efficiency.

The reason we have selected Tempra 24 plus is due to its modest requirement that can easily fit into any household without much upgrade hassles. You can always go for a bigger or smaller model based on your hot water demand.

Features

1.         GPM and Temperature rise

Temperature Rise        92°F    73°F    54°F    37°F

Flow Rate       1.5 GPM         2.25 GPM       3.0 GPM         4.5 GPM

2.         Noiseless working:

Its quiet and noiseless working gives you’re the best satisfaction in hot water and peaceful life.

3.         Advanced Flow Technology:

Who doesn’t like to have continuous hot water with no chance of running into cold water, if you are also one of them then Stiebel Eltron Tempra 24 plus is your solution. Its advanced flow technology controls the water flow and makes it such that even if you overdraw hot water exceeds tankless capacity. It will automatically reduce the water flow coming to you to ensure you get the same hot water although in a lower amount.

4.         Warranty:

With seven-year leakage protection and a three-year part warranty, you don’t need to be anxious for any kind of abrupt problem that tankless may face.

Certifications

Lead-free compliance as well as certification by UL and CSA.

Unit’s requirements

      This module needs the following requirements for proper functioning; 

  • Minimum flow rate required is 0.5 GPM
  • Water pressure supported between 30-150 psi
  • Voltage demand is 240V
  • Wattage consumption is 24000 Watts
  • Breaker recommended are 2 x 50A
  • Required Wiring is 2 x 6 AWG
  • Water and gas connection of 3/4 in. NPT

Specifications

  • Color: white
  • Weight: 16.1 Pounds
  • Dimensions:

Pros

  • Advance flow technology allow uninterrupted hot water flow
  • Quiet Operation
  • Best in budget tankless electric water heater
  • Digital Dial Temperature Control

Cons

  • Not design for colder region

Why you should buy this?

It is one of the most customer-friendly units there is in the market. It has easier and precise temperature control, which gives you a continuous stream of water. It has quiet working and modulates its operations to ensure you bigger savings.


4. EcoSmart ECO 27 tankless water heater

Budget Pick

Best Budget Tankless Water Heaters for Hard water

EcoSmart ECO 27 Electric Tankless Water Heater
EcoSmart ECO 27 Electric Tankless Water Heater

EcoSmart ECO 27 is a tankless water heater that is known for being the best electric tankless water heater. Mainly because it gives a high hot water output as well as in budget. An ECO 27, like other electric water heaters, give you the highest energy efficiency. For ECO 27 it is 99.8% and its self-modulating technology allows up to 50% energy saving. This means that its operations are going to cost you half the money you used to spend on operating storage (tank) water heater.

ECO 27 is also user-friendly in terms of the temperature setting. It comes with a digital temperature dial control that allows temperature change in 1 degree so that you can achieve the temperature that you desire most.

Eco 27 is also an amazing choice against hard water. It contains copper and stainless-steel components, making it more durable and corrosion-resistant. Hence, there will no calcium deposit on the heat exchanger and neither will the heat exchanger have to overwork to transfer heat to the water. Hence tankless water heater doesn’t have to suffer from lower energy efficiency or a shorter lifespan.

Features

1.         GPM and Temperature rise

Temperature Rise        65°F    55°F    45°F    35°F

Flow rate         2.28 GPM       3.35 GPM       4.10 GPM       5.27 GPM

2.         Self-modulating technology

Self-modulating technology brings your energy efficiency to a higher level. The self-modulation technology lets the tankless use minimum resources to heat the water to meet your hot water demands. Similarly, use different levels of operation to fulfill your demand.

3.         Warranty

Lifetime warranty on the electronic component, parts, and heat exchanger. However, there are certain conditions that need to be fulfilled to avail this like professional installation and periodic maintenance.

Certifications

An ECO 27 is certified by CSA, UL 499, and is listed by ETL.

Unit’s requirements

      This module needs the following requirements for proper functioning; 

  • Voltage demand is 240V
  • Recommended Breaker are Three 40A Double Pole
  • Wiring requires 3 x 8 AWG
  • Wattage consumption is 27000 watts
  • Amperage demand is 113A
  • Water connection support ¾ in. NPT
  • Activation flow rate demand is 0.25 GPM
  • Water pressure for optimum use is 25-150 psi

Specifications

  • Color:White
  • Weight: 13.75 pounds
  • Dimensions: 17 inches in height, 17 inches in width, and 3.75 in-depth

Pros

  • Reliable copper and Stainless-Steel components
  • It boasts a remarkable energy efficiency of 99.8%.
  • Inexpensive
  • Can work with hard water.
  • Save 50% of the operational cost as energy Saving

Cons

  • Require professional installation to avail lifetime warranty

Why you should buy this?

An ECOSMART ECO 27 is a perfect unit for those who are looking forward to saving costs as well as time. It provides instant hot water, not to mention the energy efficiency of this tankless heater is incomparable. It the most budget-friendly and resistant tankless water heater out there.


5. Rheem RTEX-24 tankless water heater

Best 240V Tankless Water Heaters for Hard water

Rheem RTEX-24 Electric Tankless Water Heater
Rheem RTEX-24 Electric Tankless Water Heater

Rheem RTEX-24 is a tankless water heater that helps you with hard water problems. It uses 3 copper immersion heat exchanger that gives it excellent heat transferability. Copper immersed heat exchangers are resistant to scale deposit hence, you don’t need to fear heat exchanger failure due to scale deposit. However, you still need to flush your tankless water heater at regular intervals to prevent slogging in pipes.

A Rheem RTEX -24 also gives a sufficiently high hot water capacity and noiseless working so that you can enjoy your life to the fullest.

Features

1.         Modulation technology:

With it, modulation technology and RTEX -24 always work at an operational level that best meets your demands so that you only pay for what you use.

2.         GPM and Temperature rise:

Temperature Rise        82° F   66° F   55° F   41° F   27° F

Flow rate         1.0 GPM         2.0 GPM         3.0 GPM         4.0 GPM         6.0 GPM

3.         Digital Temperature Control Dial allows temperature change in 1° degree:

Sometimes, having close to the best is not enough. Similar is the case with hot water, having the perfect temperature is nothing less than bliss. RTEX -24 lets you enjoy the perfect temperature through its 1° temperature change.

4.         Noiseless operations:

From time to time having a peaceful time is more precious than anything else. A RTEX -24 understanding of your needs comes with a noiseless operation that ensures a peaceful life.

5.         Durable Copper immersion Heat Exchanger:

Copper heat exchangers have 20 times more heat conductivity, which means that they can heat 20 times more efficiently than other heat exchangers.

6.         Warranty:

5-year heat exchanger and 1-year parts warranty.

Certifications

ETL, UL, and CSA certified

Unit’s requirements

      This module needs the following requirements for proper functioning; 

  • Minimum Activation flow rate demands is 0.3 GPM
  • Water pressure for normal operations is 25-150 psi
  • Voltage demand is 240V
  • Requires three breakers of 40A
  • Recommended Wire is 8 AWG
  • Water connection support ¾ in. NPT

Specifications

  • Color: Grey
  • Weight: 17.8 pounds
  • Dimensions: 17.62 inches in width, 18.25 inches in height, and 3.5 in-depth

Pros

  • 99.8% energy efficiency
  • Durable Copper immersion heat exchanger
  • Noiseless working
  • Easier Installation
  • Inexpensive

Cons

  • Lower output in colder temperature

Why you should buy this?

Rheem Rtex-24 is known for its durability and efficiency, which makes it more special than other tankless water heaters. It hardly disappoints you in any conditions so, having a Rheem Rtex-24 will be an amazing decision against hard water.


6. Rheem RTGH-95DVLN-2 tankless water heater

Best Indoor Tankless Water Heaters for Hard water

Rheem RTGH-95DVLN Tankless Natural Gas Water Heater
Rheem RTGH-95DVLN Tankless Natural Gas Water Heater

Rheem RTGH-95DVLN-2 is part of the Rheem high efficiency condensing tankless water heater series. It is a heavy-duty tankless water heater with a durable Stainless Steel heating heat exchanger that makes it an optimum solution to hard water.

Features            

1.         Built-in Condensate neutralizer:

Built-in condensate neutralizer neutralizes the acid and corrosive precipitate produced as a result of natural gas combustion.

2.         GPM and Temperature rise

Temperature Rise        35° F   45° F   60° F   80° F   100° F

Flow rate         9.5 GPM         8.5 GPM         6.4 GPM         4.8 GPM         3.8 GPM

3.         Overheating protection:

A safety feature to protect the tankless unit from overheating the water and heat exchanger.

4.         Self-diagnostic system:

Rheem RTGH-95DVLN-2 features a self-diagnostic system that tells you when it is time for maintenance and repair. Therefore, you don’t have to waste time tracking dates.

5.         Recirculation pump kit-Ready:

With this tankless unit, you don’t have to make preparation before installing a recirculation pump. You can easily install the recirculation pump without the need to do much. With a recirculation pump, you don’t need to drain the cold water in pipes or have to keep on waiting for the hot water. A Recirculation pump will bring the cold water in the pipe back to the unit to heat up. Hence, the water in pipes also remains hot so you get instant hot water as soon as you open the tap.

6.         Warranty

A five-year warranty on the heat exchanger and parts with a one-year labor warranty.

Certifications

Certified by CSA, AHRI, UL, and Energy Star

Unit’s requirements

      This module needs the following requirements for proper functioning; 

  • Flow rate for activation is 0.4 GPM
  • Water pressure support 30-150psi
  • Voltage need is 120V
  • Water and gas connection support ¾ in. NPT
  • Venting support 3 in. Schedule 40 PVC, Direct Vent
  • Minimum/Maximum BTU requires 11,000/199,900 BTU

Specifications

  • Color: Metallic Grey
  • Weight: 79 pounds
  • Dimensions: 27.5 inches in height, 18.5 inches in width, and 9.75 inches in depth

Pros

  • Uniform energy factor of 0.93
  • Recirculation pump kit-ready
  • There is enough hot water to support four outlets

Cons

  • Doesn’t have recirculation pump

Why you should buy this?

The Rheem RTGH-95DVLN Water Heater is a high-efficiency condensing gas tankless water heater. Being highly efficient, the unit consumes less energy and yet provides enough hot water to support four outlets. The stainless steel heating heat exchanger makes it more durable and resistant to hard water corrosion.


7. Rinnai RUR199iN tankless water heater

Best Natural Gas Tankless Water Heaters for Hard water

Rinnai RU199iN RRU199iN, RU199in-Natural Gas/11 GPM
Rinnai RU199iN RRU199iN, RU199in-Natural Gas/11 GPM

Rinnai RUR199iN is a part of the Rinnai super efficiency series. It is a high-end product and is designed to provide the highest efficiency of 93%. Although, it may not look like it a 93% energy efficiency is extremely high when it comes to the gas-powered tankless water heater.

A Rinnai RUR199iN is a condensing tankless water heater which means that it even utilizes the hot exhaust fumes to heat water using a second heat exchanger. This second heat exchanger does bring the water heater to the desired level but preheat the incoming water to some level so that the primary heat exchanger can bring it to the desired temperature easily.

It works based on the following steps.

•           The cold water enters the unit.

•           Moving on it gets transferred to a secondary heat exchanger that uses the heat to hot exhaust fumes to pre-heat the cold water to lukewarm to mild hot level.

•           After passing through the secondary heat exchanger, it gets transferred to the primary heat exchanger who does most of the work. The primary heat exchanger uses natural gas or propane combustion to bring the lukewarm water to the desired temperature.

Features

1.         Modulation technology:

A Rinnai RUR199iN uses a different level of flame to heat water depending upon the water demand.

2.         GPM and Temperature rise

Temperature Rise        40°F    55° F   70° F   85° F   100° F

Flow rate         9.8 GPM         7.0 GPM         5.5 GPM         4.5 GPM         3.9 GPM

3.         Wi-Fi Technology:

A Rinnai RUR199iN comes with Wi-Fi remote control that allows you to monitor and manage your tankless operations using your mobile phone. Now, you don’t need to go to the tankless water heater turn on/off the unit or change the temperature setting before you can enjoy your shower. Its simpler controls using wifi technology allow ease of peaceful life.

4.         Ultra-Low NOx

Its latest technology enables it to release a minute quantity of NOx which makes it more eco-friendly than its comparative gas tankless counterparts.

5.         Warranty

Being an expensive unit, it also is covered with a superior warranty. For the heater exchanger, the warranty is 15 years or in case usage exceeds 12,000 hours. So depending on which condition is fulfilled first, the one that expires faster will be the actual warranty. It is also accompanied by 1 year on labor cost and 5 years warranty on parts replacement.

Certifications

This unit is energy star certified, AHRI Certified and CSA certified

Unit’s requirements

      This module needs the following requirements for proper functioning; 

  • Minimum flow rate for activation is 0.4 GPM
  • Water pressure supported 50-150 psi
  • Voltage demands 120V
  • Water and gas fittings use ¾ in. NPT
  • Venting supports concentric venting (2 in. by 4in. or 3in. by 5in.) with stainless steel or twin Schedule 40 PVC (2 in. or 3 in.)
  • Minimum/Maximum BTU requires 15,000/199,000
  • Condensate Drain compatible with ½ in. NPT

Specifications

  • Color: Silver Metallic
  • Weight: 64 pounds
  • Dimensions: 31.3 inches in height, 18.5 inches in width, and 11.45 in-depth

Pros

  • Moderately Quiet working
  • Uniform energy efficiency of 93%
  • A maximum flow rate of 11 GPM
  • ThermaCirc360 works like a recirculation pump

Cons

  • Expensive

Why you should buy this?

A Rinnai RUR199iN is not exactly the cheapest tankless water heater available in market. But it does hold its own against all its competitors. Its single unit price starts from around $1800 and may cost you $3000 with the installations. Which may seem a lot for first time buyers but its performance, design and features are unmatched by any other gas tankless water heaters.


8. Takagi T-H3-DV-N tankless water heater

Staff Pick

Best Condensing Tankless Water Heaters for Hard water

Takagi T-H3-DV-N Condensing Tankless Water Heater
Takagi T-H3-DV-N Condensing Tankless Water Heater

Takagi is an excellent tankless brand backed by its world’s leading Japanese technology. Its state-of-the-art technology and durable parts make it an excellent choice against hard water. Takagi T-H3-DV-N is a condensing unit and being a condensing tankless water heater, it uses dual heat exchangers. Its primary heat exchanger is powered with natural gas combustion and is made of copper that giving 20 times more heat transferability. Hence, the heat transfer from the heat exchanger to water is extremely fast. While the secondary heat exchanger is powered by hot vapors and fumes produced by the combustion of gas and transfer their heat to warm the water. The second heat exchanger is made of stainless steel to protect it from corrosion due to hot vapors and fumes.

Features

1.         Modulation technology:

You can get maximum efficiency due to tankless water heater smart technology. The smart technology complements your hot water needs with the least resources consumption by using multiple operational levels.

2.         GPM and Temperature rise

Temperature Rise        35° F   50° F   65° F   80° F   100° F

Flow rate         10 GPM          7.5 GPM         5.8 GPM         4.8 GPM         3.8 GPM

3.         Overheating and Freeze protection:

With overheating and freeze protection, you don’t need to fear your tankless water heater overheating and scalding you. As its safety feature will cut off the power upon exceeding a certain temperature. While its freezing protection prevents water from getting frozen in the tankless water heater and damaging the unit.

4.         Troubleshooting diagnostic codes:

Its troubleshooting diagnostic codes help you diagnose the problem that the tankless water heater may suffer from.

5.         Ultra-low NOx

Comply with the SCAQMD rule for ultra-low NOx.

6.         Warranty

15-years for the heat exchanger and a 5-year warranty for all parts.

Certifications                                

AHRI CSA certified, Energy Star Certified.

Unit’s requirements

      This module needs the following requirements for proper functioning; 

  • Minimum flow rate for activation 0.40 GPM
  • Recommended Water pressure is 15-150 psi
  • Voltage demand is 120V
  • Water and gas connection compatible with 3/4 in. NPT
  • Venting supports 3-4 in. diameter Schedule 40 PVC
  • Minimum/Maximum BTU requires 15000/199,000 BTU

Specifications

  • Color: White
  • Weight: 71 pounds
  • Dimensions: 24.88 inches in height, 17.75 inches in width, and 11.25 in-depth

Pros

  • Energy Efficiency of 93%
  • Durable Stainless-Steel and copper Parts
  • Diagnostic error codes
  • Freeze and overheating protection
  • Energy Star Certified

Cons

  • Need condensate drain
  • Heavy

Why you should buy this?

The Takagi T-H3-DVNG is a condensing tankless water heater that uses dual heat exchangers for efficient performance. It requires minimum maintenance and operates on natural gas or liquid propane to provide hot water for your needs. It’s high energy efficiency saves you money by lowering the monthly utility bill expenses. while its durable build makes it a great solution to hard water.


Buying Guide : What To Look for In a Best Tankless Water Heater for Hard water

Among the various tankless brands with each having its different models, it is hard to know which tankless water heater will be a good choice against hard water. However, there are a couple of factors that you can look for in order to find a tankless water heater that works great against hard water.

Non-corrosive Material heat exchanger:

It would not be wrong to say that a tankless water heater’s heat exchanger suffers the most from hard water. It is because, upon heat hard water, minerals are separated from water which then gets deposited on the heat exchanger. This way, the heat exchanger gets caked in limescale which prevents the transfer of heat from the heat exchanger to the water. Hence the heat exchanger operates for longer to heat the water and this places a burden on the heat exchanger. Ultimately, the risk of heat exchanger failure increases. A heat exchanger made of non-corrosive material prevents the deposit of limescale hence your tankless water heater achieves a longer lifespan.

A heat exchanger made of copper or stainless steel is a good choice. A copper heat exchanger has 20 times more heat conductivity which allows it to heat water even if the water contains a lot of impurities. While stainless steel prevents scale deposit and is also durable. However, as stainless steel is expensive it is mostly found in high-end natural gas water heaters.

Shutoff valve:

Shutoff valves are a great addition to a tankless water heater. Some of the manufacturers provide them with tankless water heaters. In case a tankless unit doesn’t have them, you need to purchase them separately. The reason they are essential is that with hard water, you have to do periodic flushing of tankless water heater but it is not so convenient to shut the whole water flow through the house. A shutoff valve allows you to cut the water and gas supply connection to the tankless unit while you do its flushing.

Temperature rise:

Never rely on the tankless water heater’s labeled hot water capacity. They are not accurate as they depend upon the incoming water temperature. Just like when you cook the water, warm water will boil faster as compared to ice-cold water. Similarly, tankless water will need more time to heat colder water instead of warm. Therefore, you need to match your incoming water with the temperature rise that the tankless water heater will give and judge that whether it will be able to satisfy your needs.

AwardDesignTankless heater reviewsRetailer
Best Electric Tankless Water Heaters for Hard water
Best Pick1. Siogreen SIO 18 tankless water heater
Check Price
Best Outdoor Tankless Water Heaters for Hard water
2. Takagi T-KJr2 tankless water heater
Check Price
Best Tankless Hot Water Heaters for Hard water
3. Stiebel Eltron Tempra 24 Plus tankless water heater
Check Price
Best Budget Tankless Water Heaters for Hard water
Budget Pick4. EcoSmart ECO 27 tankless water heater
Check Price
Best 240V Tankless Water Heaters for Hard water
5. Rheem RTEX-24 tankless water heater
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Best Indoor Tankless Water Heaters for Hard water
6. Rheem RTGH-95DVLN-2 tankless water heater
Check Price
Best Natural Gas Tankless Water Heaters for Hard water
7. Rinnai RUR199iN tankless water heater
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Best Condensing Tankless Water Heaters for Hard water
Staff Pick8. Takagi T-H3-DV-N tankless water heater
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Recommendation:

If limited supply is not a problem for you or you are capable to install multiple point-of-use tankless water heaters then SioGreen SIO 18 is best for you. In 2022, this is the finest tankless water heater for hard water. A Siogreen Sio 18 reduces the limescale such that Sio 18 tankless water heater needs to be flushed one time in the same period as other tankless water heaters need to be flushed four times.


Conclusion:

Modern tankless water heaters have come up with numerous means to fight against hard water. The most effective of which is to use a heat exchanger and other components made of non-corrosive material. Still, as its name suggests, a tankless water heater’s primary objective is to heat water hence its main focus is on giving you hot water luxury with ease and comfort.


Frequently Asked Questions

Do tankless water heaters do well with hard water?

Yes, tankless water heaters do much better with hard water compared to the tank water heater. Mainly because a tankless water heater operates for a much smaller time than a tank water heater hence a smaller scale deposit. However, they still need to be flushed once a year to ensure the highest efficiency and longer lifespan.

How long will a tankless water heater last with hard water?

The answer to this query relies on your level of maintenance and the hardness of your water. A tankless water heater can last 20 years which is its normal lifespan if you regularly flush it once a year or more based on your water hardness level. A 0-60 ml/Liter is considered as soft water, 61-120 ml/Liter is considered as moderate 120-180 ml/Liter is considered as hard water. While exceeding 180 is called very hard. Hence, the greater the water hardness the more you must flush your tankless unit of sediments for it to last its whole lifespan.

What is the best water heater for hard water?

There are a number of tankless water heaters that can work well with hard water. However, the common thing among them is that their heat exchanger is made of non-corrosive material. Heat exchangers made of copper, stainless steel, and quartz are very effective against sediment and limescale deposits and give the heat exchanger a higher efficiency and durability resulting in a longer lifespan.

Does a tankless water heater need a water softener?

It is true that many manufacturers recommended installing a water softener system on your tankless water heater. As a tankless water heater, the main purpose is not to deal with hard water but to tackle the problem of heating water efficiently. This means their priority is to bring hot water to you hence it is better to install a water softener system to deal with hard water. However, there are certain tankless water heaters that can cope up with the hard water for a longer duration.


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Emma Johnson
By Emma Johnson

Hi, This is Emma. Author at “BestHeaterGuide.com”. I am a graduate of Mechanical Engineering. Currently researching on heating technology. However, I have learned many home heating techniques and still learning home heating technology. And I love to share my research and reviews.

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