Best Tankless Gas Water Heater Reviews, FAQ’s & Buying Guide (Top-Rated In 2024)

by Curtis Grossi | Last Updated: March 13, 2024
Tankless Gas Water Heater Reviews

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As per the U.S. Dept. of Energy, tankless hot water heaters are more efficient than tank water heaters by up to 34%. Small households consuming not more than 41 gallons a day can save about 34% on utility bills, while those consuming about 86 gallons of hot water can save up to 14%.

Tankless water heaters are either gas, solar, or electrically powered. Gas tankless water heaters are confirmed to be more efficient and will save you about 100 dollars a year in energy costs when properly handled and maintained under the best working conditions.

The market has hundreds of tankless gas water heater brands and models, but here, we will outline the 7 best tankless gas water heaters that you can buy this year.

Are you in a hurry? If you don’t have time to read our article, then please use the links below to quickly find the best tankless gas water heater for you on Amazon.

Top 3 Best Tankless Gas Water Heaters


Tankless Gas Water Heater Reviews – Top 7 Picks

1. Rinnai RUC98iN Ultra Series – Space-saving Design

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Rinnai RUC98iN Ultra Series is a super energy-efficient gas-powered water heater boasting an Energy Factor of .96 and Energy Star Qualification. It is ideal for both residential and commercial applications as its compact size and unique design allows it to fit well in any indoor setting. The heater is only 61.7 pounds heavy, 10-inch wide, and 16-inch high.

On its control panel is an advanced digital display, power button, and water/gas control. The unit is Wi-Fi ready so you can adjust and monitor its temperature right from your tablet or smartphone. And the good thing, the Wi-Fi technology keeps you updated on the kind of maintenance the unit needs.

It’s perfect for multiple applications considering its awesome output of 9.8 gallons per minute. Measuring 18.5 by 26 by 10 inches, the unit is attractively compact and small enough for indoor installation. You can set it to heat incoming water at 98 degrees Fahrenheit to 140 degrees Fahrenheit. It has Energy Star certification, which is certainly good news as you are assured of saving more on energy bills.


  • Can be installed virtually everywhere
  • Requires no extension kit
  • Super-efficient and durable
  • Operates silently and smoothly


  • Requires professional installation

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2. Rinnai V Series HE – Runner Up

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Looking for an affordable yet efficient gas-powered tankless water heater? Rinnai V series HE should be your model of choice. It ranks top among the best water heaters that can be installed indoors. It’s the perfect definition of a high-value, comfortable, and high-efficient propane gas tankless water heater.

The unit is easy to install, reliable and compact enough to be installed in small to medium households. With its 120 months residential factory warranty, you are sure getting a product that will serve you with fewer to no software or hardware issues.

This gas-powered tankless water heater is designed to deliver a whopping 6.6 gallons per minute of heated water. Rinnai V65iP HE is a super-efficient tankless water heater that packs amazing features and functions. It includes a Control-R 2.0 mobile app, which has timers and schedules, which lets you remotely control the functions of the unit. It’s simply of the best units you can invest in to enjoy a continuous supply of clean hot water on demand.


  • Has an ultra-compact design
  • Delivers 6.6 gallons per minute
  • It has a lower Nox emission
  • Boasts a maximum BTUs of 150,000
  • Quite affordable


  • You can’t return the heater if it doesn’t meet your expectations

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3. Rheem RTGH-95DVLN – Our Premium Choice

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Rheem boasts long-standing credibility in making high-performance and good-quality gas tankless water heaters. The Rheem RTGH-95DVLN is a super-economical unit to install that will save you significantly on energy bills. The unit packs condensing stainless heat exchanger alongside electronic control, which works together to boost energy conservation.

This system does not overheat due to its digital temperature control panel which efficiently controls the incoming and heating water temperatures. It comes with the option of EZ-link cable which you can use to connect two different tankless heaters in case the demand for hot water is high.

Rheem tankless natural gas water heater is designed to serve the whole house with hot water. The unit can capably produce 9.5 gallons of hot water per minute. That ensures the flow of hot water in the taps is not limited. If you have basic plumbing skills, you can easily have the unit installed in your house, thanks to its straightforward design and easy to follow user instructions.


  • Saves a lot on energy bills
  • Can be installed in a matter of hours
  • Comes with a strong 5-year warranty
  • Comes fitted with overheat film wrap to maximize safety


  • High flow rates affect its performance

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4. Eccotemp i12-NG – Best For Small Households

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Eccotempi12-NG is superior and high-end gas tankless water heater ideal for household applications. It’s designed such that it will not overheat since it comes with automatic temperature control features.

For safety, it is designed with a child locking technology to prevent any injuries due to mishandling the system. This system cannot work efficiently if installed above 5000 feet. The standard elevation is 200 feet if you want it to perform as per your expectations.

Eccotemp i12-NG is suitable for serving small homes, vacation cabins as well as cottages. The horizontal stainless steel vent kitallows for easy installation, ensuring your chosen plumber won’t waste the whole day trying to get it installed. It also has a 120-volt power cord that is used to power the digital displays and internal exhaust fan.

Its flow rate is 4 gallons per minute which ensures a continuous flow of hot water when needed. It consumes 1.07 Amps when in operation and uses 2 watts when not in use making it economical.


  • It’s designed to last
  • It’s quite cost-effective
  • The installation process is not so complex
  • It has a good and quality design


  • Can only be used in small households

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5. Gasland Outdoors BE158 1.58GPM 6L – Our Budget Pick

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Gasland outdoor tankless water heater takes safety to another level, thanks to the overheating control, anti-freezing, and flame failure functions. It’s one of the best outdoor water heating systems, which boasts a lightweight design and super performance. You can easily move it from one point to another to avail of hot water anywhere you need it.

The unit has a simple design making installation easy. Gasland BE158 water heater has an amazing output of 41,000BTU/Hr, which delivers optimal hot water flow continuously. The unit packs high-end features to fully control the temperatures, ensuring you can achieve the desired water temperatures and flow rate.

This outdoor gas-powered hot water heater also includes digital energy-saving function, which can enable you to save about 11.5% on energy bills. It has a propane heater exchanger and burner which are designed to consume less gas and produce minimal noise. It produces 1.58 gallons of hot water per minute, which though not so good ideal for most small to medium household hot water applications.


  • Packs a simple to understand installation guide
  • Easy to handle and maintain
  • Quite energy-efficient
  • Super strong and durable


  • A few complaints of randomly shutting down sometimes

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6. Takagi T-K4-OS-NG – Best For Commercial Settings

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Takagi gas-powered tankless T-k4 is a wall-mounted and compact designed whole-house heater that provides continuous hot water on demand. It’s the ideal choice of water heater for heating water in residential and commercial settings. The unit can efficiently deliver 8 gallons of hot water in a minute, which makes it the most powerful choice among the units we have reviewed.

And since it can be installed outdoors out of sight, it’s really a great investment that offers real value for money despite its high-price. Also, it comes with a built-in power venting system, which works to eradicate the need to install a complex system.

It can be installed anywhere to provide hot water for 3 bathrooms. With this unit, you are getting a range of high-end and efficient safety features, including exhaust and water temperature safety control for monitoring the hotness of the delivered water, air-fuel ratio sensor for optimizing fuel use, and cutoff fuse ideal for preventing issues with overheating.


  • Able to serve there uses at once in a house
  • Remote control for easy accessing
  • Outputs 8 gallons of hot water per minute
  • It is energy star certified
  • Packs internal freezer protection system
  • You do not need extra venting


  • Not ideal for areas with extra low temperatures
  • Its installation is limited to outdoors only

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7. Noritz NRC66DVNG

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Noritz NRC66DVNG one of the smartest and most trending gas-powered tankless water heating systems from Noritz company. The in-built temperature controllers and two modern heat exchangers made of copper and steel making this type of water heating system efficient and economical to use.

It has terminations and adapters which provide a room for more venting options. However, venting can be done using 40/80 PVC, CPVC and pp pipes. The installation kit for the unit is IK-WV-200-1-XX-LF valve, is sold-out separately with the tank. It is also fitted with rain caps and atmospheric kits for conversion.

Noritz tankless water heater has a gas consumption rate of 15,000 and 120,000 BTU. The water flow rate of this tankless water heater is 6.5 gallons per minute ensuring an endless supply of hot water in your house. The Noritz exchangers come with a warranty for twelve years. This system is designed to serve small families, and so it may not be perfect for offices and bigger households.


  • It is quite efficient
  • Endless hot water supply
  • Easy installation
  • It is a modern design


  • Can only serve small homes

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Comparison Chart Of The Best Gas Tankless Water Heaters

ModelBrandPriceOur RatingFlow RateWeightDimensions
Rheem RTGH-95DVLN 9.5 GPM Indoor Direct Vent Tankless Natural Gas Water HeaterRheem$$$$$8.69.5 GPM79 pounds18.5 x 9.8 x 27.5 inches
Rinnai V Series HE Tankless Hot Water Heater: Indoor InstallationRinnai$$$8.46.5 GPM49.6 pounds13.9 x 8.8 x 23.6 inches
EZ Ultra HE Natural Gas Condensing Tankless Water HeaterEZ Tankless$$$10.0
3.4 GPM31 pounds27 x 14.5 x 6.5 inches
Rinnai RUC98iN Ultra Series Indoor Natural Gas Tankless Water Heater, Twin PipeRinnai$$$$$9.29.8 GPM82 pounds10 x 18.5 x 26 inches
Takagi T-K4-OS-NG Tankless Water Heater, Natural Gas, OutdoorTAKAGI$$$$8.88.0 GPM38 pounds8.5 x 13.8 x 20.3 inches
Eccotemp i12-NG Tankless Water HeaterEccotemp$$8.03.0 GPM28.9 pounds17 x 29 x 11 inches
Gasland BE158 1.58GPM 6L Outdoor Portable Gas Water HeaterGASLAND$8.41.58 GPM15.5 pounds11.8 x 6.1 x 17.3 inches

Buying Guide – Factors To Consider When Choosing Your Gas Tankless Water Heater

a) Type Of The Tankless Gas Water Heater

Tankless gas water heaters come in multiple choices, which depend on the application and installation spots. There are portable, outdoor, indoor, and whole-home types of gas-powered tankless water heaters.

1. Indoor Gas-powered Tankless Water Heaters

The indoor type of tankless water heaters is designed to be installed indoors either under the sink, in the bathroom or kitchen. The heating machine is designed such that it will be installed indoor alongside the venting kits so it can efficiently release gas out.

2. Outdoor Gas-powered Tankless Water Heaters

These are designed to be installed outdoors outside the kitchen or bathroom walls. Unlike the indoor tankless water heaters, the outdoor counterparts need no ventilation. However, they should be installed securely so they are not affected by severe weather conditions.

3. Whole-Home Tankless Water Heaters

The whole home tankless water heaters are ideal for making hot water available for bathing, washing hands or doing laundry. These types of gas-powered tankless water heaters have higher flow rates and are more powerful.

4. Portable Gas-powered Tankless Water Heaters

Portable gas-powered tankless water heaters are compact in size and have a small light-weighted heating machine. These tankless water heaters are versatile enough to be installed virtually anywhere, including outdoors or RV. Their flow rate is quite low, so they are ideally best for basic household hot water uses.

See also: Best Portable Water Softeners 

b) Size And Capacity Of The Water Heaters

The first-hour rating or recovery rate of the tankless water heater is a crucial consideration. The recovery rate of a water heater describes the maximum hot water amount a water heater can heat and dispense within one hour after the cold water tap is started.

Natural gas tankless water heaters have first-hour ratings ranging from 41 to 131. The recovery rate of natural gas heaters is higher than the one for electric water heaters.

Before you buy a tankless gas water heater, check its capacity and size since it will also affect the recovery rate. You can find tankless gas water heaters in sizes from 20 to 80 gallons. Check the flow rate and temperature rise of the water heater to discover the best unit with a higher flow rate.

Most gas tankless water heaters generate two to five gallons of water a minute, though smarter and bigger brands deliver up to 8 gallons a minute.

c) The Energy Efficiency Rating

The energy-efficient rating of tankless gas water heaters is indicated in the form of EF which stands for the ratio of energy outputted as hot water in comparison with the overall energy used by the hot water heater in 24 hours.

Tankless water heaters with higher energy factor are usually more energy-efficient and usually the perfect choices for those who want to save on energy bills. It makes real sense to weigh the value you are getting from the model you want to purchase and the best way to do so is to get a unit that has a higher Energy Factor.

But always keep in mind that higher EF does not automatically translate to lower costs of operation. Some electric water heating systems have higher EF ratings but cannot compare with gas heating systems with slightly lower Energy factors since gas is a bit cheaper and offers lower annual operating costs.

d) Design, Durability, And Compactness

A standard tankless gas water heater can last for about ten years when properly maintained and carefully handled. The durability of any water heating system is especially dependent on the design and brand. Some brands are more durable and will serve you for more years as compared to others.

Gas-powered tankless heaters from top brands are smart and compact besides offering many wall placements. The majority of the models outlined above provide outdoor and indoor installation alongside an anti-freeze kit. Some are small enough to be fitted under closets or cabinets for a more convenient point of use.

e) Ease Of Installation And Operation

The biggest problem with investing with gas-powered tankless water heaters is mostly about the issue of complex installation requirements. Most models and brands are simply easy to run and do not require having any unique qualifications or skills. Once they are properly installed following the manufacturer’s instructions, some models will only require adjusting the temperature on its dial.

The smarter models support remote control to deliver hands-free operation. Whichever you choose, ensure you are getting a unit that is easy to install and operate. Read the manufacturer’s user instructions and user reviews to know if the model you are about to choose is easy to run and would not require hiring a professional to install.

f) Consider The Room Temperature Of The Tap Water

Determine the room temperature of the incoming water and evaluate the rate at which the heater needs to raise the temperature to make it hot enough for household use. The room temperature of the water channeled to your house can either be cooler or warmer, depending on the climate of the area you live in. The room temperature of most tap waters ranges from as low as 35 degrees to as high as 70 degrees.

Most systems heat water to around 120 degrees, meaning there is really a big difference between the temperatures of the incoming water to that of the dispensed water. The optimal GPM for most water heaters is around eight to nine. However, if the water heater has to heat the water by around 70 degrees, the GPM will be cut by half. All models and brands of water heaters have a manufacturer’s literature that offers the GPM at varied incoming water temperatures, the reason you should pay close attention to such considerations.

g) Core Options To Compare

When evaluating gas tankless water heaters, you have to compare and choose between condensing, condensing hybrid, and non-condensing.

I. Condensing

Also known as the second generation tankless water heaters, the condensing systems feature a primary and secondary heat exchanger. The secondary heat exchanger reuses the heat released by the exhaust so they can heat water. That adds to the optimal unit efficiency by up to 94%. Condensing hot water heaters can be vented by the use of PVC, though they are a bit costly to procure and install.

II. Non-Condensing

The non-condensing water heaters are the most popular units, which have a primary heat exchanger only and boasts an efficiency factor of about 0.85. Non-condensing technology has been used in Europe and Japan for decades now. These are the most reliable water heaters to buy since they employ tested and proven technologies alongside high-end designs.

III. Condensing Hybrid

The condensing hybrid gas tankless water heaters have a small storage container, which is usually about two gallons in size. The tank is ideal for storing the hot water reservoir, which aids eradicate the efficiency lost due to short draws. It aids to increase the energy efficiency factor of the water heater to about 0.96.

These types of gas tankless water heaters operate at an efficiency level of 94% with few cases of degradation triggered by short draws. You can vent the condensing hybrid tankless water heaters by the use of PVC.

h) Your Household Water Flow Rate Needs

Tankless water heaters generate water on demand, and so they must have water flow rates compatible with your household’s hot water demands. Most water heater models have a max flow rate rating pinned on the product specifications.

The GPM capacities of the different brands and models of water heaters we have just outlined above are virtual and so you can easily compare them with the range of their temperature rises, ensuring you can determine their abilities based on the climate of the area you live in.

Unlike other options, Takagi’s series have two standard gas types, propane, and natural gas with some of the products having higher GPM than others. 

i) Standout Features Of The Gas Tankless Water Heaters

Tankless water heaters heat and channel hot water to the water pipes in your house whenever you put on the faucet. The speed at which water is heated and supplied depends chiefly on the superiority of the water heater. Gas tankless water heaters generate water on demand and so it’s vital to choose one that is sized as per your building’s water demands.

If the incoming water is super cold and the household hot water demands are quite higher, you should settle for a unit with the highest GPM achievable. More advanced gas-powered tankless water heaters have unique and smart features like the ones we have outlined below, which should also be a core consideration when shopping.

Wi-Fi Compatible

The most advanced tankless units featuring a digital connectivity link up to your smartphone wirelessly, allowing you to efficiently monitor and adjust the hot-water and gas usage. They as well provide timely data on the condition of the unit, ensuring you can schedule regular maintenance.

Microprocessing Technology

Smarter tankless units feature computer-controlled microprocessors that read the temperature of incoming water and adjust the unit’s output energy accordingly, ensuring steady tap water temperature and reduced energy consumption.

Advanced Security Features

The smarter tankless units pack a range of high-end and useful safety features such as anti-scald protection alongside a temperature controller to inhibit scalding, ICAD monitors combustion, Flame failure monitor for detecting the flame failure, and overheat limit wrap.

Customer Support And Care

Customers want to be assured of quality care and support services when buying products online. Buying gas tankless water heaters is no exception. Top tankless water heater brands are only at the top because they manufacturer high-quality products and deliver optimal customer care services at all instances.

When deciding which of the many products to buy, you cannot neglect the credibility and reliability of the product manufacturer’s customer care and support. Make sure you are getting a trusted tankless water heater manufacturer with a solid reputation offering premium care services.

Video: Tankless Water Heater Installation Plumbing And Gas Connections

Frequently Asked Questions (FAQ’s)

There are tons of tankless water heaters out there customers can compare and make a choice. However, most of them want answers to their questions so they can make the right decisions. Here are the main questions about gas tankless water heaters and the answers.

What Is A Gas Tankless Water Heater?

Tankless water heaters also are known as instantaneous are upgraded versions of traditional tank-type water heaters but without a tank. They are more efficient solutions, which don’t generate standby heat loss.
When you put on the water taps, the unit will heat the water and then transmit it via a pipe. Most gas-powered tankless water heaters use a gas burner and can efficiently supply constant hot water flow for different commercial and household uses.

Are Tankless Gas Water Heaters Worth It?

Compared to their electric counterparts, tankless water heaters are way more efficient and reliable. Once you invest in a gas tankless water heater, you can save 5% to 69%, depending on the Energy efficiency rating of the model and the water consumption rates in your household. Some models are super energy-efficient and can save you up to $300 yearly.

What Is The Downside Of A Gas Tankless Water Heater?

Gas tankless water heaters cost a fortune upfront alongside having output limitations. They cost more than conventional tank water heaters by up to 40% and their hot water output levels are not so good. They as well have higher BTU requirements compared to traditional tank water heaters.

How Efficient Are Gas Tankless Water Heaters?

Gas tankless water heaters are about 34% more efficient than traditional tank water heaters. Smaller homes consuming less than 86 gallons of hot water a day can enjoy energy-efficient ratings of about 24 to 34%, while those consuming more than 86 gallons per day enjoy energy-efficient rates of about 8 to 14%.

Can I Replace My Gas Tank Water Heater With A Tankless Option?

Thinking of replacing the old-fashioned gas-powered tank water heater with a tankless option? Experts know how to efficiently address the specific installation requirements, including choosing the best venting pipes and helping connect to the most stable gas supply line within your areas of residence.

Should I Try Installing My Gas Tankless Water Heater Myself?

If you have basic plumbing skills, you can easily and quickly get your unit installed on the most suitable spot indoors or outdoors. However, if you have no skills, it can prove to be a potentially dangerous endeavor, which at the end may lead you to lose more money and wasting your precious time.

That’s why it’s always strongly recommended you get a professional to safely and professionally install the units for you. Get a factory-trained and licensed plumber or electrician as they will be in a better position to deliver a cleaner job.

Which Special Requirements Should I Meet Before Getting A Gas Tankless Water Heater Installed?

Tankless water heaters heat the water when needed and so there is always a need for a bigger size of the gas line. These units are pilotless, though they require electricity to ignite the gas. Before you order that gas tankless water heater, ensure you are connected to a bigger gas line.

Can I Install A Gas Tankless Water Heater In My Attic?

The answer to this question is either yes or no. it simply depends on the kind of plumbing piping on the attic. In some instances, installing a tankless water heater can lead to water siphoning condition, which could damage your system when the water supplied in the lines is not enough.

Are There Restrictions To Where Tankless Water Heaters Can Be Installed?

Of course yes. In some cities and states, you cannot install certain models of tankless water heaters. That’s why it’s good to confirm with the local authorities prior to buying a water heater so you don’t end up with a model that is prohibited in the city or state you live in.

My Tankless Water Heater Does Not Show The First-Hour Rating, Why?

No matter the model or brand, tankless water heaters don’t show the first-hour rating. Tankless water heaters don’t start with a tank of hot water, which makes it impossible for them to show the first-hour rating as it’s the case with tanked options.

However, tankless water heaters indicate an accurate figure of the gallons per hour rating, which is simply the total gallons of hot water the heater can produce within an hour.

At What Temperature Should I Heat The Incoming Water?

When determining the temperature at which to heat the incoming water, so many factors come into play. The first one is the temperature of the incoming water. If the incoming water has an extremely low temperature, you must heat it at a higher temperature.

The second factor is the level of hotness you want to achieve. If the incoming water has a higher temperature but the temperature you want to achieve is higher, you have to heat the water at a higher temperature.

Do I Need A Permit To Install My Gas Tankless Water Heater?

In most states, you must get a permit from your local building department before you try installing any tankless water heater. The rules and permit regulations vary based on state, so try confirming with your state’s local building department first.

How Much Can I Save After Installing A Gas Tankless Water Heater?

If you sacrifice the high upfront cost to get a high-end gas tankless water heater model, you are sure to save some good amount of money in the long run. The amount you save will, however, depend on the cost of gas, the hot water demands in your household as well as the room temperature of the incoming water.

How Durable Are Gas-Powered Tankless Water Heaters?

A high-quality model from a top brand will serve you long enough to ensure you earn optimal value from your investment. The best models designed for top materials will last anywhere from 15 to 25 years before they need to be replaced.

However, the lifespan of any gas-powered tankless water heater is chiefly dependent on the care and maintenance the unit receives. Properly maintained units can last more than the predicted manufacturer’s lifespan.

Are The Operation Costs Of Tankless Water Heaters Lower?

Most tankless water heater models have an Energy Factor of 0.82, which quite higher than that of most tank-type water heaters. It’s fully confirmed that water heaters with higher EF are a bit cheaper to operate compared to those with a lower EF.

Why Are Gas Tankless Water Heaters More Expensive Than Tank Water Heaters?

Gas tankless water heaters pack the best of features and design. Most have solid stainless steel and copper, which are durable enough to last for more than 15 years. The high cost of tankless water heaters is usually because of the CATII stainless steel ideal for venting alongside the many utility rebates and tax credits you get once you install these high-end water heating systems.

Bottom Line

Gas-powered tankless water heaters are superior options, which are widely accepted because of their sustainability and eco-friendliness. The key reason behind most people loving these units is because of their ability to heat water super-fast without consuming a lot of energy.

Having one installed will greatly save you on energy bills alongside ensuring you have quality access to hot water when the need arises. We have given you an outline of the best 7 gas-powered tankless water heaters along with the key features to look for when buying the best tankless water heater for your home.

Look into each of them carefully and compare them based on the features, design, and performance so you can choose one that suits your household’s hot water demands and personal budget, as well.

Curtis is the founder and owner of He is the lead guy concerning all the water-softening accessories in this site's guides and reviews. If he is not writing a reviews, guides or any other useful tips, you will find him testing them to find out their suitability. He is passionate about softening water. You will find him extremely helpful and always willing to educate the general populace all there is concerning water and its effects on their health and appliances.