10 Best Tankless Water Heater In 2021 [Reviews & Buying Guide]

Thinking of buying the best tankless water heater would be the smartest decision you have ever made. Yes! that’s true. As they are smart enough to provide continuous supply of hot water, require less space because of their slim size, last but not the least they use less energy than the storage tank, which results in saving $100 or more yearly on your utility bills, relying on the water use. 

Longevity is another big advantage of top rated tankless water heaters. They last 20 years more than their conventional counterparts(storage tanks) which have a maximum 10 to 15 years of life span. 

I can’t promise you of giving the review of the perfect tankless water heater as nothing is perfect. But I assure you I would suggest the right water heater that would meet your particular requirements of water usage. 

best tankless water heater

After thorough research and reviewing different models, I have listed down the reviews of the best and top rated tankless water heaters, including from hot sellers to economical choices. So, be wise while buying!

The 10 Best Tankless Water Heater Top Reviews

Let’s explore tankless hot water heaters reviews in detail in order to pick the best one for your home. 

Note: Best rated on demand Tankless hot water Heaters require special fitting, space and climate also affects its working. So, you must read the buyer’s guide in order to avoid having any bad experience.

ImageProductDetails  Price
ecosmart 27 electric tankless water heaterEcoSmart ECO 27 Electric Tankless Water HeaterMax GPM: 6.6
Item Weight: 10.98 pounds
Power Type: Electric
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Rinnai V65EN RV65eNRinnai V65eN Tankless Hot Water HeaterMax GPM: 6.5
Item Weight: 47.4 pounds
Power Type: Natural Gas
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Rinnai RU199iN RRU199iN, RU199in-Natural GasRinnai RU199iN Sensei Super High Efficiency Tankless Water HeaterMax GPM: 11
Item Weight: 64 pounds
Power Type: Natural Gas
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Rinnai RU180iN RRU180iN, RU180in-Natural GasRinnai RU180iN Sensei Super High Efficiency Tankless Water HeaterMax GPM: 10
Item Weight: 64pounds
Power Type: Natural Gas
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Stiebel Eltron Tempra Plus 29 kW, tankless electric water heater with Self-Modulating Power TechnologyStiebel Eltron Tempra Plus 29 kW, tankless electric water heaterMax GPM: 6
Item Weight: 10.37 pounds
Power Type: Electric
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Eemax EEM24013 Electric Tankless Water HeaterEemax EEM24013 Electric Tankless Water HeaterMax GPM: 2.4
Item Weight: 8.08 pounds
Power Type: Natural Gas
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Stiebel Eltron Tankless Water Heater – Tempra 24 Plus – ElectricStiebel Eltron Tankless Water HeaterMax GPM: 5
Item Weight: 1 pounds
Power Type: Electric
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EcoSmart ECO 11 Electric Tankless Water HeaterEcoSmart ECO 11 Electric Tankless Water HeaterMax GPM: 3
Item Weight: 6.5 pounds
Power Type: Electric
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Rheem RTEX-18 18kW 240V Electric Tankless Water HeaterRheem RTEX-18 18kW 240V Electric Tankless Water HeaterMax GPM: 4.4
Item Weight: 14.8 pounds
Power Type: Electric
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Rinnai RL 94IP Tankless Water HeaterRinnai RL Series HE+ Tankless Hot Water HeaterMax GPM: 9.4
Item Weight: 44.2 pounds
Power Type: Propane
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Tankless Hot Water Heater In 2021 Comparison Chart

Table Of Contents

1. EcoSmart ECO 27 Electric Tankless Water HeaterTop Pick

EcoSmart ECO 27 Electric Tankless Water Heater
  • 50% saving on heating cost
  • 0.3GPM Activation flow
  • Efficient and durable
  • Sleek design fits anywhere

Ecosmart as a young company brought revolutionary change in the race of best tankless water heaters. They introduced Patented Self Modulating Technology in tankless heaters to provide on demand hot water even at the lowest temperature.

Are you living in an extreme cold temperature with the problem of having endless hot water in multiple fixtures at a time? But meanwhile your budget is too tight… Then nothing to worry, as EcoSmart Eco 27 is the right choice for you as this does not burdenise your pocket as well as space. This unit is one of among the top rated water heaters.

Patented Modulation System

Built-in Patented Modulation System helps reduce electric bills up to 50%. This unit is up to 99.8% energy efficient and uses energy only when it is required. Precise Temperature Control is another super cool feature of this EcoSmart Eco 27. 

The company claims that this unit has a generous and decent flow rate,  you can have three showers and a sink in use simultaneously without any delay in the supply of hot water. 

According to the US Energy Department, tankless heaters are 24 to 34% energy efficient. Though ECO27 is not energy star certified, it is 99.8% energy efficient. 

Flow Rate

But the real experience says that the flow rate and energy efficiency depends on the inlet water temperature. If the temperature drops down to 37°F, this unit has the capacity to provide a flow rate of 3 gallons per minute for two showers at a time without running out of hot water. When temperature gets a bit warmer, its flow rate and efficiency jumps high to 6 GPM. Consequently, you can run 4 showers simultaneously. 

Its low activation flow rate .03GPM is comparatively more amazing than others. Where other instant hot water heaters flick on at least at 0.5 GPM to heat water, this on demand water heater stimulates quickly to low flow hot water requirements. 

EcoSmart Eco 27 is the ultimate economical choice for the habitants of the Northern United States where temperature is too low but this is equally useful for the Southern United States where temperature is relatively higher. 

Advance Features

Some advanced features make EcoSmart Eco 27 the best tankless water heater on the market. They are: 

  • EcoSmart Eco 27 has built-in precise technology that brings heating cost down. Its advanced mechanism heats water only on demand. 
  • Digital Temperature Control ability allows to increase the water temperature by 1-degree increment.  
  • Modern technology enables to display the exact water temperature passing through the pipes. 
  • Efficient and durable as copper and stainless components are used in manufacturing. Also replacement is easy.
  • Space saver by saving 12 cubic feet of storage space due to compactness  and sleek design. 
  • This on demand hot water heater needs 27kw, 240 volts and three 40 Amp double poles and draws 113 A.    

Robust And Long-Lasting

EcoSmart instantaneous hot water heaters don’t become rusty easily.  Its most advanced technique to combine copper and stainless steel reinforce its long-lasting and conduction ( ability to transmit heat from one side to others at high temperature).

Adjustable Temperature

Modern digital interface allows to show the temperature which can be easily adjusted between 80°F – 140°F and enough for household use. Moreover, the 1-degree increment temperature option is an amazing but rather unfeasible attribute. 

To tackle the high demand of hot water, install a valve to throttle down the instant hot water flow rate.

Before buying the EcoSmart heater, one must sort out the hot water requirements and electrical fitting of the house and the right size of the hot tankless water accordingly. Recommended electrical measurements are 27kw, 240 volts, 3 double pole 40A breakers, 112.5 AMP, 3 (8) require wire, and Amperage draw :113A

Specification

  • Dimensions: 17H x 17W x 3.625D inches ;Pipes fittings :3/4 inch NPT.
  • Digital temperature control in 1-degree increments allows control of hot water.
  • Activation Flow: 0.3 GPM.
  • Electrical requirements: 27 kW, 240 volts, (3) 40 required breakers, 112.5 maximum power (AMP), (3) 8 required wire, and Amperage Draw:113 A.

PROS

  • 99.8% energy efficient, resulting in minimum energy loss i.e. 0.2%.
  • Generous flow rate regardless of the colder and warmer temperature.
  • Excellent flow rate in economical pricing.
  • Compactness and light weight resolve the space shortage issue.
  • No regular maintenance is required but annually inspection is enough.
  • Eco friendly, durable with lifetime warranty.

CONS

  • Not energy star certified.
  • Temperature fluctuation expected if valves are not installed and hot water demand increases in cold climates.
  • No warranty will be given if the product is not registered within 30 days after purchase.

2. Rinnai V65eN Tankless Hot Water Heater, Large Best Outdoor Model

Rinnai V65eN Tankless Hot Water Heater, Large, White: tankless hot water heater
  • Max BTU’s 120,000
  • Max Energy Factor 0.82
  • Lightweight and Compact
  • Meets California and Texas NOx Emissions Standards

Rinnai is the name of trust providing reliable and durable tankless water heaters since 1912. That is why, this company has become the number one seller of best on demand water heaters in the United States and Canada.

Flow Rate

Rinnai V-Model is available in both indoor and outdoor versions whereas Rinnai V65eN is featured to install outdoors only. It uses natural gas to work with the depth between 10,300 BTU (Minimum) to 150,000 BTU (Maximum). It provides a smooth flow rate up to 6.5 GPM (gallon per minute) even for multiple fixtures simultaneously. 

Energy Efficient

Though it is not Energy Star Qualified but still you can save on your utility bills as its Uniform Efficiency Energy Range is between 0.79 to 0.82. The Rinnai V65en series is an ultimate combination of High Efficiency and natural gas, heats water on demand which saves energy from being wasted. 

Another key point is that watt consumption is fairly amazing, consumes 57 watts when being operated, 2 watts only on standby, and 104 watts when the anti frost protection mode is on. 

Advance Features

Some of the special features are:

  • You can control the temperature range: The preset temperature range starts from 98°F to 120°F, but you can widen the range to a maximum of 140°F.
  • Error code indicator is integrated: makes it easy for you to sort out any possible issue and fix that accordingly. Moreover, the user manual contains all error codes along with their possible remedies. 
  • Temperature lock feature is amazing: as it keeps the water temperature constant in case of any unauthorized and sudden modifications in the water temperature.
  • Integrated with Wi-Fi monitoring.
  • Certified for installation in manufactured (Mobile) homes.
  • Complies with South Coast Air Quality Management District 14 ng/J or 20 ppm NOx emission levels: which is useful to keep the environment clean.
  • Compatible with the full line of Rinnai Digital Controllers: apart from the provided standard controller, this unit can sync with any Rinnai Digital Controller purchased separately
  • Offers decent residential warranty:  10-year warranty on heat exchanger, 5-year on parts, and 1-year warranty for the labor.

Durable And Reliable

The most compelling evidence is that this inline hot water heater has a robust structure, made of stainless steel which saves from rusty sediments and increases the lifespan. All these qualities make this unit named Rinnai V65eN the best tankless water heater.

The most surprising fact is that it comes in the size of a suit briefcase with the dimensions of 9.6 x 14 x 24.3 inches and it weighs 47.4 pounds. 

Easy Installation

The installation process for this unit is pretty simple and elaborated in detail in the user guide. As long as the user properly uses the provided instructions, this tankless hot water heater would act smartly. 

Rinnai V65eN as best hot water heaters have got the Amazon’s Choice badge because of the positive reviews given by the happy and satisfied customers. No downside has been mentioned yet except this is suitable for small to medium homes or remodels. Moreover, 3 to 4 fixtures run smoothly with any shortage of hot water. 

Specifications

  • Dimensions: 9.6 x 14 x 24.3 inches.
  • Max Energy Factor 0.82.
  • Max BTU’s 120,000.
  • Max Energy Factor 0.82.
  • Outdoor Installations.
  • Meets California and Texas NOx Emissions Standards.
  • Light weight and Compact.

PROS

  • Endless hot water on demand.
  • Save valuable space because of the compact size.
  • Multiple fixtures simultaneously.
  • Temperature lock is included.
  • Sync with Wi-Fi monitoring.

CONS

  • Sometimes, it uses more amps than a standard 120 amps.
  • Not good for hard water.

Read Also: Best Point Of Use Tankless Water

3. Rinnai RU199iN Sensei Super High Efficiency Tankless Water Heater – Best For Large Families

best tankless water heater Rinnai RU 199iN
  • Circ-Logic technology
  •  Sensei SE+ Super High Efficiency
  • Up to 11 GPM hot water flow rate
  • Residential Factory Warranty

Rinnai Ru199 is a Sensei SE series with most advanced techniques such as super high efficiency, energy star qualified and voice activation command. The versatility of this unit is the availability for both commercial and residential usage, and can be operated with both Natural Gas or Propane. Moreover, both indoor and outdoor versions are available to purchase as per users’ need. 

High Flow Rate

One of the most outstanding features of this unit is its highest GPM flow rate which is 11GPM hot  water flow rate depending on the inlet water temperature. This robust flow rate is sure to provide instant hot water for maximum 7 fixtures at once. As a result, 2 or 3 persons can enjoy a hot shower, along with the dishwasher and laundry activities are carried out on the other side. Therefore, it is wildly known as best gas hot water heater.

The coolest fact to know is that its on demand hot water flow rate varies from 0.26GPM to 11GPM. The minimum GPM is ideal for the low demand needs of hot water such as shaving, and hand washing etc. 

Advance Features

Some of the most amazing features are:

  • Able to produce 11GPM hot water flow rate depends on the incoming water temperature.
  • BTU ranges from 15,000(mini) to 199,000(max) makes this unit super fast to fulfill instant hot water demand for the whole family simultaneously.
  • Up to 0.93% energy efficient, brings a drastic cut down in electric bills.
  • Provided with Circ-Logic technology, enables you to regulate recirculation patterns to supply hot water when you need it. 
  • Compact and wall-mounted design resolves space issues.

Advanced Circ-Logic Technology

Circ-logic technology is one of the advanced mechanisms that offers hot water instantly when you need it. This feature stops the water being cooled in the pipe, and provides hot water immediately after turning on the taps without keeping you in waiting mode. So, you not only save water but your time also. To get benefit from this technology your house must have return line installation otherwise, thermal bypass valves are required.

Control-R Wi-Fi Module

Another key feature is Wi-Fi Ready, allowing you to control, manage, and monitor the unit remotely. This Control-R Wi-Fi Module makes it easy to control hot water supply from any corner of your home, and also you can activate recirculation if installed. Thus, it can be termed as the best tankless water heater.

Indoor Installation

Rinnai RU199iN is featured for natural gas: indoor installation. This is equipped with freeze protection down to 22°F. In like manner, to optimize the venting system, a valve is installed between the turbofan and combustion chamber to stop cold air entering. 

RU199iN Indoor installation offers flexible options makes it best gas tankless water heater. It provides both concentric and PVC/CPVC venting. Through concentric venting, one pipe enters fresh air in and another sends the exhaust out. 

Before buying, must check the electric requirements of your house, must be compatible with the units’ requirements to get optimal performance. 

Specifications

  • RU199iN Sensei SE+ Super High Efficiency Tankless Hot Water Heater – Natural Gas: Indoor Installation Only.
  • Up to 11 GPM hot water flow rate (varies by groundwater temp).
  • 15,000 BTU (Minimum) / 199,000 BTU (Maximum).
  • Circ-Logic technology allows you to set recirculation patterns that coincide with your typical habits. Hot water is available when you need it!
  • Endless hot water for your entire home.
  • Residential Factory Warranty – 120 months (heat exchanger), 12 months (labor), 60 months (parts).

PROS

  • Provides residential warranty: 10 years for heat exchanger, 5 year parts warranty and 1 year for labor.
  • Circ-Logic Technology saves water and time.
  • Integrated with voice activation command and Control-R Wi-Fi Module Technology.
  • Temperature lock stops unwanted changes to water temperature.
  • Comes with the required valves such as 2 connection valves and 1 TP valve.
  • Energy star qualified.

CONS

  • A bit expensive unit.
  • Not certified for commercial use in Texas, or residential use in Utah.

Read Also: Best RV tankless Water Heater

4. Rinnai RU180iN Sensei Super High Efficiency Tankless Water Heater – Upgrade Pick

Rinnai RU180iN Sensei Super High Efficiency Tankless Water Heater, 10 GPM - Natural Gas: Indoor Installation:tankless water heater reviews
  • ENERGY STAR Qualified
  • Uniform Energy Factor of .92
  • Equipped with Rinnai Circ-Logic
  • Simultaneous uses at multiple fixtures

Rinnai RU180iN is known for its best and optimal performance regarding uninterrupted supply of hot water on demand. RU180iN employs SENSEI technology, which presents the easiest user experience and installation process with multiple locations options to enhance its performance. 

The self-compensate feature optimizes the performance of this unit by dealing with low and fluctuating gas pressure issues smartly. 

Excellent Flow Rate

Surprisingly, this RU 180iN SENSEI series boasts a maximum 10GPM flow rate which is pretty sufficient to entertain 5- 6 persons at the same time without running out of hot water. So, this is an ideal choice for medium to large families.

Flow rate may be varied in different areas depending on the temperature of incoming water. The minimum flow rate is 0.26GPM sufficient for common tasks with low demand of hot water.  

Circ-Logic Technology

Coupled with a recirculating mechanism, Rinnai RU180iN delivers fast hot water whenever you need it and wherever you are. This Circ-Logic technology is designed to set the recirculation pattern conform to your instant hot water needs. This saves your time and water.

In addition if your recent plumbing configuration does not have the devoted return line to meet the circ-logic requirement, nothing to worry.  A thermal bypass valve is the best alternative. 

NSF Certified

Moreover, this heater is not only energy star qualified but also NSF certified, and got approval for commercial applications. The 0.93% EF and condenser help reduce energy loss and boost saving.  

Longevity And Durability

Corrosion-resistant technique is another excellent feature that upgrades its longevity. The stainless steel heat exchanger resists corrosive nature and ensures durability and long-lasting functions. These features make this unit the most reliable water heater.

Slim design, wall-mounted and flexible venting features relieves you from the space issues.   

Specification 

  • SENSEI SE + Super High Efficiency.
  • Maximum 10GPM  flow rate ( inlet water temperature matters).
  • Equipped with circ-technology, provides hot water instantly.
  • User friendly warranty.
  • wi-Fi Ready.

PROS

  • Wi-Fi compatible: to control and manage the unit remotely.
  • Uninterrupted hot water supply for up to 6 fixtures simultaneously.
  • Enhanced combustion design boosts optimal performance.
  • Easy installation process and serviceability.
  • Available in both natural gas and propane.
  • Amazing residential warranty: 10 year for heat exchanger, 5 years on parts damage, and  year for labor.

CONS

  • Comparatively expensive.

Read Also: Best Whole House Tankless Water Heater

5. Stiebel Eltron Tempra Plus 29 kW, tankless electric water heater – Best Electric Model

Stiebel Eltron Tempra Plus 29 kW, tankless electric water heater with Self-Modulating Power Technology & Advanced Flow Control; instant hot water heater
  • Proven reliability
  • No venting required
  • Constant temperature output
  • Sleek design fits anywhere

State of the art mechanisms like authentic operations, superior quality and genuine functioning of Stiebel Eltron Tempra Plus has been successful to win the trust of its users. Tempra Models are included in top selling brands on Amazon on account of their optimal and reliable performance. 

Endless Supply Of Hot Water

Stiebel Eltron Plus 29kw model is prominent for several outstanding features and provides an immediate solution to the demand of instant hot water to its users. This powerful 29kw electric tankless water heater is designed to fulfill the uninterrupted hot water demand for whole house and commercial applications especially in cold climates with temperature drops below 40°F.

Advanced Flow Control technology

Its built-in Advanced Flow Control technology provides a remarkable experience to the customers by providing consistent hot temperature water through various faucets simultaneously. Situationally, this automatic technique reduces the flow rate considerably if flow demand exceeds the heater’s capacity, and ensures a consistency at temperature level regardless of exceeding water demands. 

As a result, you don’t experience an unpleasant temperature fluctuation with high flow demand occasionally. And the company claims that this feature is not found in other tankless water heater brands.

Ideal Flow Rate

Being the most efficient on demand water heater, its three heating modules provide a smooth transition of heating power from minimum 21.6kw to maximum 28.8kw on 240 volts. This unit supplies 3.1GPM water flow at 42°F (2 fixtures running at a time), and maximum flow is 6GPM at 72°F (4 fixtures functioning simultaneously) temperature, sufficient for the home with 3 bathrooms in warmer areas, 2.5 baths in  moderate climates and 1.5 baths for colder areas respectively. 

Self-modulating Technology

Self-modulating technology in Tempra 29kw ensures that the minimum amount of energy is used to heat water. So, this unit is 99.5% efficient and saves 15- 20% when compared to electric tank heaters. 

True Thermostatic Temperature Control, an intelligent feature, in collaboration with full power-modulation automatically adjusts its power output to accommodate the variation in inlet water temperature and flow rate, consequently desired output temperature of hot water is available.

For efficient and optimal performance, an anti-scale filter is suggested to save this unit from pre-mature failures produced due to minerals present in hard water. 

True microprocessor mechanism maintains steady output temperature regardless of the variations in flow rate whereas other tankless heaters do not provide steady temperature if the flow changes.

Smart Digital Temperature Display

Smart digital display and appropriate dial selector allow you to adjust the required output water temperature such as 64°F for hand washing, 107°F for hot shower and upto 140°F for commercial applications. 

Tempura Eltron requires 208 – 240volts with 21,600 – 28,800 watts respectively, draw 150Amps, 3x 40 Amp double pole breakers and 3 x 8 gauge copper wiring, and ¾ NPT Pipe fittings. 

So, identify your hot water needs and recognize your electric panels if you are interested in buying this unit.

Specifications:

  • Reliability is proven.
  • Venting free.
  • Compact design fits anywhere.
  • Energy efficient.

PROS

  • Sensor detects flow demand automatically.
  • Most precise temperature control.
  • Equipped with Advanced Control Flow to provide constant temperature.
  • Self-modulation feature adjusts electrical usage and saves energy.
  • Uninterrupted supply of hot water.
  • Warranty: 7 years for leakage, 3 years parts and workmanship.
  • Easy to install and use.

CONS

  • A bit expensive.
  • Water filter required for optimal performance.

6. Eemax EEM24013 Electric Tankless Water Heater – Best Point-Of-Use

Eemax EEM24013 Electric Tankless Water Heater, Blue; instant water heater
  • Compact size
  • Self-modulating technology
  • Sleek design fits anywhere
  • Continuous Supply of hot water

Eemax EEM24013 tankless water heater electric is especially designed to fulfill the instant hot water demands of small families requiring minimal flow rate and point-of-use applications. 

To get the terrific performance, you must know your water demand and the capacity of this unit, as this unit does not allow multiple showers simultaneously with ideal flow rate. 

Flow Rate Of Water

This unit is capable of delivering endless hot water for one sink only in colder climates depending on the inlet water temperature. Sufficient to provide continuous hot water for 1 sink and shower at the same time in relatively warmer climates. The flow rate of this unit is 0.3GPM.

Thermal Energy Efficiency

Eemax 24013 is certified to 99% Thermal Energy Efficiency, helping save on energy. Price is economical and you save upto 50% on water heating costs. 

Self-modulating technology adjusts power consumption according to hot water requirements smartly. And this energy efficient feature reduces the electric costs up to 20% as a whole. 

Moreover, 90% are smaller than the traditional water tank, and can even be placed in a kitchen cabinet.

Corrosion Free

Insulated materials like Copper and brass are involved in manufacturing, so nothing to worry about leakage and sediment. 

The sad thing to know that this unit is unable to fill a shallow tub but good for showers. Makes annoying noise when it cycles on. 

To have amazing experience with this product, you must know your hot water demands and electric panel requirements which are 1 x 60 Amp breaker, 1 x 6 AWG wires and 240 volts. 

Specifications

  • Eemax EEM24013 provides instant, consistent and endless hot water.
  • Stylish look with Digital Temperature Control display.
  • Adjusts the temperature with 1-degree increment ranging from 80°F to 140°F.
  • Slim enough fits anywhere.

PROS

  • Instant, constant and endless hot water is available all the time.
  • Insulated material avoids water leakage.
  • 5-year leakage and 1-year parts warranty included.
  • Energy saving and money saving.
  • Simple installation and electric cables, connectors and NPT adapters are included.

CONS

  • Irritating voices when switches.
  • Can’t fill large bathtubs.
  • Slowly adjusts temperature.

7. Stiebel Eltron Tankless Water Heater – Amazon’s Choice

Stiebel Eltron Tankless Water Heater – Tempra 24 Plus – Electric, On Demand Hot Water, Eco, White; best water heater
  •  Noise free
  • Eco friendly unit
  • Advanced Flow Control
  • powerful copper interior heating system 

Living in areas with cold temperatures is very challenging in many ways. Uninterrupted supply of hot waters for showers and other house chores feels shooting in extreme cold.

Robust Tankless Heater

Then, Tempra 24 plus is one of the robust electric tankless water heaters, a perfect choice to fulfill instant hot water demand for whole house applications in Northern USA, Canada and the areas with frigid temperature. 

This unit allows you to operate 2 hot showers, including tub filling, which is a really super cool function of this model. 

Flow Rate Sensor

Integrated with a flow rate sensor, which regularly sends important data to the microprocessor. And this microprocessor-controlled feature heats the water according to the set temperature. So, you can save 15- 20% on electricity. 

Flow Rate Measurement

This model provides 2.6GPM at 42°F (1.5 fixtures)  and 5GPM at 72°F allowing you to run 3 water applications at the same time. The sizing chart of Stiebel Heaters helps you to choose the right model.

Electric Requirement

To get maximum benefit of this model, your house has the recommended electrical service which are 24 kw, 240 volts, max. Amperage draw 100 A, min. required breakers 2 x 50 A DP, required wire size 2 x 6/2 AWG and min. recommended electric service 150A. 

Advanced Flow Control Technology

Advanced Control Flow German Patented Technology is an exclusive feature of the Tempra series. As the unit’s sensor detects that hot water demand is increasing more than the heater’s capacity, this Control Flow automation adjusts the flow to maintain the comfort. It slightly reduces the flow to carry on steady and uninterrupted hot showers. 

Auto-Modulation

This is an Eco friendly unit. Its auto-modulation feature along with ability to electronically measure water flow helps savings 15 – 20 % energy. Interestingly, the saving monitor displays how much you save on energy costs. 

The sleek design with wall mounting feature saves space as well as no venting is required. This model has earned the Amazon choice badge because of outstanding functionality.

Specifications:

  • Auto-modulation helps save energy.
  • Electronically controllable water flow.
  • Display monitor exhibits cost saving.
  • Solid copper heating chambers.
  • Maintains constant hot water through Advance Flow Control technology.

PROS

  • No annoying sounds, totally silent operations.
  • Up to 99.5% energy efficient.
  • Sleek design and no expensive venting required.
  • Safety proven: Shut down automatically in case of overheating.
  • Smart self-modulating energy saves energy.

CONS

  • Water filter required to deal with hard water.
  • Not suitable for old houses as electrical panel upgrade is required.
  • Sediment filter and regular flushing is required regularly.

8. EcoSmart ECO 11 Electric Tankless Water Heater – Best For Small Families

EcoSmart ECO 11 Electric Tankless Water Heater, 13KW at 240 Volts with Patented Self Modulating Technology; on demand hot water heater
  • Lifetime warranty
  • Uniform Energy Factor:0.98
  •  60% on your water heating cost
  • Patented self modulating technology

Eco 11 electric tankless water heater is the hot seller on amazon. This model is suitable for a small sink, low flow shower head, toilet, and office breakroom and other low flow applications.

This on demand water heater has dual functions: it can be used as a point of use in the areas with pretty cold climates and can be configured as a whole house tankless heater in warmer areas.

Flow Rate in GPM

Climatic condition matters alot for the optimal performance of this model. Eco 11 is the ultimate choice for inhabitants living in locations with temperature 67°F or above. The water heating capacity of this model is 2 gallons per minute which is sufficient for one shower head with a 1.5 gpm flow and two sinks running simultaneously while the incoming water temperature is 67°F and output temperature setting is 105°F. 

In cold climates, this unit works great when used as a point of use with a sink or other low flow appliances. Interestingly there is a direct relation between water flow and temperature rise. So, when a high temperature rise is required in extreme cold, it will be restricted in the number of fixtures. You can run only 2 sinks with low flow at a time.

 Like other models of EcoSmart, this unit also ensures the frugal use of the required amount of power to heat the water through its amazing self-modulation technology. So, you save a handsome amount on energy and water heating costs yearly. 

Exact Temperature Display

This unit displays the exact temperature of running water. Also, the temperature can be easily reset through a convenient dial on the front part of this unit. 

Convenient size of this unit saves up to 12 cubic feet of space. This Eco friendly model 99.8% is energy efficient. 

Suitable Electric Fitting

To consider the suitable electric fitting required for the particular unit is essential for the optimal performance of the unit. 

This unit requires 13 kw, 240 volts, max Amperage 57, required breaker 1 x 60 Amp, and 1 x 6 AWG wire gauge. 1/2 NPT adapters are also included.

Specifications

  • Lifetime warranty.
  • Save up to 60-percent on your water heating cost with an ECOSMART electric tankless water heater.
  • Never run out of hot water with an ECOSMART tankless water heater.
  • Patented Self Modulating Technology and design.
  • ECOSMART tankless water heaters are 99.8-percent energy efficient. Uniform Energy Factor:0.98.

PROS

  • Equipped with a self-modulating mechanism that intelligently adjusts the required energy based on the hot water need.
  • Digital temperature Control with increments of 1-degree.
  • Stainless steel heat exchange.
  • Thermal auto safety.
  • Durable heating elements that are subject to easy replacements.
  • Lifetime warranty for electronic, exchanger and elements.
  • Convenient size frees up the huge space as the tankless heater is 90% smaller than the storage tank.

CONS

  • Warranty does not cover the cost of labor or any incidental damage.
  • Limited flow rate in cold climates.
  • Require regular maintenance.

9. Rheem RTEX-18 18kW 240V Electric Tankless Water HeaterBest Budget Model

Rheem RTEX-18 18kW 240V Electric Tankless Water Heater, small, Gray; best hot water heater
  •  LED display (+/1 degree accuracy)
  • Adjust power automatically
  • Durable Copper immersion
  • hreaded for easy replacement

Everyone does not need a large amount of hot water, not even simultaneous use of instant hot water. Rheem RTEX-18 as a mid range model is the ideal choice for small families, apartments and medium- sized homes with upto 2 to 3 persons. 

Flow Rate in GPM

This is the best seller electric tankless heater as it provides 4.4 GPM flow rate but with a low price. This unit supplies endless hot water for point of use or other multiple applications depending on your preferences. 

In cold climates, it has the ability to deliver an adequate water flow rate up to 2.5 GPM for a shower and a sink. Whereas in warm climate, this unit provides up to 4.4 GPM flow rate sufficient for 2 showers and 2 sinks

Advanced Self-Modulation Technology

Advanced self modulation feature intelligently adjusts the required power after sensing the hot water demand. Subsequently, you save on energy bills. 

Coupled with two heating elements, this unit ensures regular and quick supply of hot water continuously. As two heating elements heats water more rapidly as compared to one heating element. So, you don’t have to wait for long to have hot showers.

Durable And Reliable

Made with copper immersion, these two heating elements are resistant to high temperature and corrosion. So, this unit is durable and lasts long. 

The installation of this unit is pretty simple. You don’t need any professional installation which is pretty expensive. The cool thing to know is that the package contains all the required hardware. 

LED Display

Integrated with external thermostatic control, it has a digital LED display with 1-degree increment. So, you can set your desired water temperature as per your demand.   

Eco18 is the best choice for indoor use as its operations are noise-free.

This RTEX=18 requires 18 kw, 240 Volts, 2 x 40 amp breakers and 8 AWG wire. Must upgrade your electric panel accordingly for the primal performance of the heater.

Specifications

  • External digital thermostatic control with LED display (+/1 degree accuracy).
  • Most advanced self-modulation, adjust power to meet hot water demand.
  • Durable Copper immersion two heating elements, field Serviceable. Flow Rate- up to 4.4 GPM.
  • Simple installation – bottom 3/4 inch NPT water connections.
  • Threaded for easy replacement, simple installation, digital temperature display.

PROS

  • Save energy, space and water.
  • All switches operate silently.
  • Robust unit, resistant to high temperature and corrosion.
  • Ideal choice with tight budget
  • Threaded for trouble free replacements.
  • Energy efficient, no more use of energy but as needed.

CONS

  • Can’t handle high flow.
  • Not suitable for large families.
  • Wiring guide is not easy to understand.

10. Rinnai RL Series HE+ Tankless Hot Water HeaterBest Whole-House Model

Rinnai RL Series HE+ Tankless Hot Water Heater: Indoor Installation, Large, Silver; inline water heater
  • Sustainable reliability
  • Affordable, efficient savings
  • Endless hot water on demand
  • Up to 9.4 GPM hot water flow rate

To buy a tankless water heater which saves both your time and money is not an easy task. You have to consider many parameters like gallons per minute, energy efficient, simultaneous use of multiple water applications providing instant hot water: incase of large families, indoor & outdoor installation if you have space issues. 

Non Condensing Water Heater

Rinnai RL94iP HE is part of Rinnai’s non-condensing propane tankless water heater. The propane acts as a fuel to operate this model, and produces more units of energy to heat water much faster than others. So, the saving period starts immediately. 

Being an efficient-burning fuel, propane tankless water heaters allow the use of multiple fixtures simultaneously without disturbing the consistency of water flow rate. 

Excellent Water Flow Rate In GPM

If we talk about the capacity of this unit, this model offers a pretty amazing flow rate up to 9.4 GPM. You can run almost 4 to 5 water appliances at the same time without running out of hot water even if you are last in the shower taking line. 

Without losing the consistency in flow, either 3 to 4 hot showers run smoothly or one shower with multiple faucets.  So, Rinnai RL94iP HE is the convenient choice for a family with 4 to 5 people with regular demand for instant hot water.

This model helps conserve both energy and water, being featured with PVC pipes, which have capacity to save heat for long. 

Circ-Logic Technology

Circ-logic technology provides you peace of mind by allowing the quick access of instant hot water through recirculation process. This circ-logic feature not only provides instant hot water but also preserves the hot water for future use. So, you don’t waste your time and water. 

This unit is robust and durable as stainless steel is involved in its manufacturing, also minimizing the danger of debris and limestone formation inside the pipes. So the heater works efficiently and lasts long.

Digital Temperature Control

You Can control the temperature ranges from 98 to 140°F through digital control. Wi-Fi monitoring mechanism gives you remote access to manage this unit from anywhere in the house.  

This is a biggest tankless hot water heater with indoor installation model, and vents directly by utilizing concentric venting systems. This model requires 115 volts.

Specifications

  • Endless hot water for your entire home.
  • RL94iP HE+ High Efficiency Tankless Hot Water Heater – Propane: Indoor Installation Only.
  • Up to 9.4 GPM hot water flow rate (varies by groundwater temp).
  • Circ-Logic technology allows you to set recirculation patterns that coincide with your typical habits. Hot water is available when you need it!
  • Residential Factory Warranty – 120 months (heat exchanger), 12 months (labor), 60 months (parts).

PROS

  • Highly efficient and preserves both water and energy.
  • Isolation and Pressure Relief valves are included.
  • Energy star certified.
  • Allows consistent flow rate for multiple fixtures.
  • Easy preventive maintenance.

CONS

  • Advanced safety features are not included.
  • Has some noise issues.
  • Warranty is not applicable in some cases.

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How to Buy Tankless Water Heater – Complete Buying Guide (2021)

tankless water heater buying guide

Instant hot water heaters are the basic need of the winter season for most of us, but when the market comes with a diverse variety of products. Then the right choice of purchasing on demand hot water heaters becomes pretty difficult.

 On increasing demand of hot water heaters, we have gathered all the factors one should consider before buying a tankless water heater. So, without wasting any time, let’s dive in.

What is a Tankless Water Heater?

As the name implies, tankless water heaters provide people hot water when they need it. Being most efficient in saving money, these tankless heaters are also free from any energy loss.

These tankless heaters are diversified into several categories depending on fuel, budget, power capability, and much more. The most basic tankless water heaters’ most basic division is based on the energy they consume for their efficient activity.

Types of Tankless Water Heaters

Fuel category for the tankless hot water heater depends on many factors, but most probably, the typical fuel types for tankless water heaters are natural gas, propane, and electricity. Every fuel has its pros and cons, and they also affect the productivity of the heater.

Natural gas tankless water heaters offer higher power output as compared to those of electrical models. Also, they can provide an ideal temperature in heating the water at a very affordable rate.

Though the natural gas is ideally low in budget, but gas tankless heaters are pretty expensive because of the technology used to make the units. Also their initial setup costs more( upto &1000) than that of an electric heater with tackling installation.

 For buying a tankless water heater with the right choice of fuel is a deliberate decision. It’s time to have a look at the description of each fuel source.

Natural Gas   

Natural gas is one of the cheapest sources, and in most cases, the connections are direct. But these heaters offer you long-time use. Also, people with high household demands prefer natural gas as they are in the budget.

But the downside of tankless heaters having natural gas as a fuel source is storing natural gas which is not at all . Therefore, these appliances are not the right choice for RV use.

You have to spend more money on completely installing the natural gas tankless heater if your house does not own an existing natural gas hookup.

 Propane Gas  

Propane gas is one of the most expensive fuels, and most people cannot fit this in the house. For a tankless water heater with propane, gas is used as a fuel. So, a portable fuel tank is an integral part of the tanks.  

These portable propane water heaters allow you to change the tanks when they have gotten empty, but this feature acts as the downside of the instant gas hot water heater as they are not appropriate for houses. But you can use them in recreational vehicles. Propane water heaters are more efficient but cost more than electric water heaters.

 Electric Supply   

Another fuel used in tankless heaters is electricity. Most of the time, people go with the electric tankless water heaters, which is an affordable choice, whether about installation or initial purchase. But the increased electricity budget can add up to the cost.

The electric tankless water heaters have special electric specifications, depending on the model. Therefore, an expensive upgrade to the current electric system would be necessary to meet the unit’s specification.

Tankless Water Heater vs. Tank

tankless water heater vs tank

Converting to the tankless water heater is trending now, but even this cannot justify the current reach and importance of tankless water heaters. Tankless water heater dimensions make it efficient  according to the choice of need.

 But for the instant and continuous hot water delivery, tankless water heaters are usually preferred by majority.

 Tank-type water heaters offer a higher flow rate as the water flows from the faucet freely without any water heating system obstacle than can slow down the water pace.

From the budget perspective, tankless water heaters are beneficial as there is no need to preheat the water or maintain its temperature that saves energy and time too to a considerable extent, and is thus easily affordable.

Initial installation of tankless water heaters is a bit pricey, but it will not be a bad deal when you enjoy a lifetime service.

Tankless water heaters are long-lasting but take time to install. On the other hand, tank-type water heaters are easy to install.

Storage tanks occupy a sufficient space whereas tankless heaters are slim and compact with wall-mounting facility can be fit easily on the wall anywhere in the house. 

How Does a Tankless Water Heater Work?

Tankless heaters help deliver the right amount of water. The working of tankless water heaters is genuinely excellent with a step-by-step heat process.

The water passes through a series of burners in natural gas and electric coils in electric heaters in every round. After passing these heaters, the water reaches the faucets from where you can use the required hot water for everyday use.

How does a tankless water heater work?

These tankless heaters are costly to install but think wisely; a one-time investment with long time usage is not a bad deal. Also, they do not run a water shortage due to fixed connections.

The temperature heat depends on the water flow and temperature coming from the direct links that vary concerning your place’s ties and geographical distribution.

How much water a tankless heater can handle depends merely on the increases in temperature degrees of the flowing water in the pipelines, and this is known as gallons per minute (GPM).

What Size Tankless Water Heater do I Need?

The next question that arises in any person’s mind when choosing a tankless water heater is the size that best suits your household and family’s demand for hot water. For this, one should know how to size a tankless water heater.

A few years back, tankless water heater sizing was a major point of interest, but now people do not look for tankless water heater sizes. Instead, they look for the type and quantity of faucets the tankless water heater will serve.

It is typically called GPM (Gallons Per Minute) or flow rate.

Determination of Power Source 

Power source ultimately depends on the user’s preferences and the current circumstances. Electric tankless water heaters are generally a better option for houses where the water demands are not too much.

Electric tankless water heaters are less expensive as compared to gas tankless heaters. But they do require a huge amount of energy to be functional. So, you have to upgrade the electric panel system of your house to get optimal performance, which is an expensive process notably. 

Moreover, they are a good choice to be used as point-of-use tankless water heaters, but normally avoided to be used as whole house water heaters due to costly electric upgrades. 

Whereas gas tankless water heaters are the smart choice, if your location has the availability of natural gas or propane. They also provide fast response time and high heat output to fulfill user’s demand efficiently.  

They are generally suitable to be used as whole house tankless water heaters, but they require expensive venting. The good thing to know is that they are available in both outdoor and indoor installation. The outdoor installation is vent-free. 

 What size tankless water heater do I need for a family of 5 members?

Similarly, a family with five members looking for hot water on demand systems will have different priorities with some of the general extra appliances including an extra half-bathroom, one more shower, an additional washing machine, a dishwasher, and a half bathroom faucet.

The overall GPMs of the appliances, as mentioned earlier, will be about 10 GPM or 28 kw electric tankless water heaters will be required, if your location is in the northern parts of the USA where inlet water temperature is relatively low.

For the southern part of the USA, only 7 GPM or 18 kw on demand hot water heaters would be convenient to fulfill hot water demand for a family of 5 members, depending on the inlet water temperature which is usually between 60°F to 80°F.

Calculation of Water Flow Rate

Tankless water heater pressure and tankless water heater flow rate are directly related to each other. The water flow rate in the tank, whether it is a storage tank or tankless water heating system, aids you in how to choose a tankless water heater for you.

The water flow rate means the amount of water that can pass through the tankless water heater when the heating system is working. Generally, we calculate the water flow rate in gallons per minute (GPM). 

There are two extremes of water flow rate, i.e., minimum flow rate (activation) and maximum flow rate. It ranges between 0.1 – 0.9 GPM.

 Minimum/Activation Flow Rate means the minimum amount of water required for activating the heating system of a tankless water heater.

While the Maximum Flow Rate is the maximum amount of water that can flow smoothly in the water heating appliance. The water flow rate and temperature rise are directly related.  

How many GPM of  hot water heater do I need? You can easily understand this with an example. For using two showers at a time, approximately 5 gallons of hot water per minute is required.

If you are using a shower faucet and washing machine, 4.5 gallons per minute will be enough. In short, the GPM for tankless water heaters will depend on the number of appliances.

 For instance, how many gallons per minute does a shower use? The average shower GPM is 2.5 gallons, which means 20 gallons of water for the average shower.

The following table will represent the general flow rate. Flow rate varies at different temperature.

FIXTUREAVERAGE FLOW RATEAVERAGE TEMPERATURE
Bath Tub4.0 GPM102°F
Shower3.0 GPM104°F
Clothes Washer2.0 GPM120°F
Dish Washer1.5 GPM110°F
Kitchen Sink1.5 GPM110°F

Temperature Rise

Temperature rise means the increase in temperature level needed for heating the incoming water according to your choice. If the heating system cannot maintain the water flow rate, you will start having cold water in the faucets.  

 Temperature rises can be calculated as:

Expected shower temperature – incoming water temperature = required heater temperature rise

 The difference between the incoming and outgoing water temperature is termed as temperature rise; for instance: the incoming and outgoing temperatures are 50 °F and 105 °F, respectively; the approximate temperature rise will be 55 °F.

Temperature rise and water flow rate have an inverse relationship that means if there is a more incredible temperature rise, the water flow rate will be low and vice versa. The temperature rise required for tankless water is also affected by the local water supply.

chart showing the relation between flow rate and incoming water temperature

The local water supply temperature varies in the regions of even the same country, like in the North U.S, the temperature rise is merely 35 degrees Fahrenheit. Also, it depends on the time that the tankless water heater will take to heat the water for usage.

Power Input (BTU)

Power Unit, measured in British thermal units abbreviated as BTU, is termed as the energy required to heat the water to a targeted temperature. The amount of energy needed to raise one pound of water temperature by one-degree Fahrenheit is one BTU.

The basic formula to calculate the power unit is:

(500 x GPM x Temperature Change = Required Power Input in BTU per Hour)


Efficiency Percentage

Condensing vs. Non-condensing

Tankless water heaters are also categorized into condensing and non-condensing water heaters in case of gas used as a fuel because whenever some gas is used in any procedure, water vapor or steam always forms due to the fuel burning and serves as the byproduct.

The pipes and ducts collect this steam and drain it out. Condensing and non-condensing tankless water heaters are separate from each other due to the change in steam release duration in the ventilation process.

Condensing 

In a condensing water heater, a particular unit is referred to as a condensing unit where residual exhaust heat is captured and reused. After this, it passes through a cooling system and gets released through ventilation with 98 percent efficiency.

Non-condensing 

There is a direct and immediate vent steam system in non-condensing tankless water heaters that can bear up the high temperatures as premium quality materials are used in their construction.

Their initial installation costs much, but as a whole, they are okay to buy. Due to the immediate ventilation system, these tankless water heaters come with an 80-85 percent efficiency rating.

Electric versus Gas Tankless Water Heaters

One can buy an electrically heated or tankless gas unit, but people prioritize their choices based on the benefits they offer. Tankless water heaters come with more extensive gas lines, but their installation is a bit hectic and expensive compared to electricity.

Gas tankless water heaters can heat water faster and supply water with a higher pressure.

Different aspects make the tankless heaters top picks based on fuel choice. Some of them are:

  • Electric tankless water heaters are more efficient than gas tankless heaters, with an EF reach of 0.98. For gas-powered water heaters, the EF reach is 0.9. The minimum water capacity is a 40-gallon tankless water heater, and in some cases, it elevates up to a 75-gallon tankless water heater.
  • Prices of natural and propane gas water heaters generally cost higher than electric tankless water heaters.
  • As for the initial cost, electric water heaters are affordable, costing between $500 to $1,000.
  • Electricity is the basic need and thus available everywhere; therefore, electric heater is easy to install. Whereas gas heaters, you must have access to natural gas or propane that is not possible in some places. 220-volt tankless water heaters are common in the market as far as the power source is concerned.
  • The maintenance of electric water heaters is easy. You just have to clean the inlet screen filter regularly. But for gas water heaters, one must have a trained technician to check it properly, and it can be expensive.
  • Gas tankless water heaters are heavier than electric tankless water heaters.

Point of Use vs. the Whole House

Any house requirements decide what type of installation the users should go with either a point of use tankless water heater or whole house tankless water heater.

The whole house gas tankless water heater usually fulfills large demand of instant hot water, and has a different installation setup where all the appliances are connected with the tankless water heater. Now you can enjoy hot water from any of the house water inlets with the residential tankless water heater.

Whereas, point of use tankless water heaters are designed to fulfill low demand of hot water and installation refers to only one appliance closer to the tankless water heater. These small water heaters are the best for a small family with two to three persons.

Pros and Cons of Tankless Water Heaters

Many questions arise when we think about buying a tankless water heater. Some of the questions are:

  • What are the advantages and disadvantages of a tankless water heater?
  • Are tankless water heaters more efficient?
  • How long do hot water heaters last?
  • What are the dangers of tankless water heaters?
  • What is the cost of installing a tankless water heater?
  • How many GPM tankless hot water heaters do I need?
  • How big of a tankless water heater do I need?

We have jotted down all the answers in detail for your ease.

What are the Advantages of a Tankless Water Heater?

The benefits of a tankless water heater do not limit to a known extent. Every instantaneous water heater comes with a variety of advantages. Some general plus points of endless hot water heater are:

benefits of tankless water heater

Saves Energy

Tankless heaters provide hot water on the spot. In addition, there is no heat loss by heating and re-heating water as the tankless heater will only process it whenever the hot water is required.

Longevity

Above all, tankless water heaters are famous for their life span that is amazing with a long service life. If a user uses the tankless water heater with proper care and maintenance, the average life of the tankless heater is about 20 years.

Replaceable Parts 

Electric tankless water heater pros and cons are noticed at a large level as they come with the facility of replaceable parts. Manufacturers have adequately taken all the facts under consideration, and with proper dedication, they have designed the heaters so that if it happens to break or leak at some point, it can be repaired and even replaced.  

Compact Design 

They come with a compact and robust design for easy and quick installation. You can mount these tankless water heaters on the wall both outside and inside the house. And no need to worry about space consumption as compared to tank storage.

Superb Supply of Hot Water

The capability of tankless heaters to supply hot water is fantastic, and every tankless heater offers heating services according to the requirements of the place. If you have the right size for your house, your family will enjoy the tankless heater’s long-lasting benefits.

Fresh Water Availability

Tankless water heater benefits the users in providing fresh water. There is no scene of water sitting in the tank in storage water heaters. You will be served with the freshwater as the connections are made directly with the pipelines.

Resultantly, your hygiene will also be okay because there will be zero chance of rusting when there is no water sitting. The tankless heater performs its duty well whenever hot water is needed, and as the demand is fulfilled, the tankless heater immediately stops the water heating process.  

Mind Relaxation

As there is no storage tank with a tankless water heater so there will be no chance of any leakage until or unless you face a significant crack in the pipelines but not directly related to the tankless heaters. They are efficient in their activity, and it rarely happens that they are having issues before the guaranteed time.

What is the Downside of a Tankless Water Heater?

Sad to know that tankless water heaters have some drawbacks. Let’s check them out:

what is the downside of a tankless water heater?

Initial Costs

Though tankless water heaters are not too costly, they demand a handsome amount of money for the initial set up. But except for the initial costs, they are easy to manage in the budget. 

Capacity Issues

As far as the demand is concerned, every house has its own specific water demands, and here it comes when most people are stuck. It may happen you have to install two large tankless appliances according to the requirements of our house.

But your apartment or house does not seem enough to compensate for two tankless heaters, so as an alternative, you can also add a small point of use for bathroom services.

Upgrading Power Resource

Upgrading power resources for the electric tankless water heaters is a must. One has to implement water heating systems with recommended electricity for delivering a larger quantity of hot water, especially in older places.

Expensive Venting

Expensive venting is required for non-condensing gas-fueled tankless water heaters.

Output Limitations 

The system’s capability should match the household’s hot water demands; otherwise, the tankless heater will not deliver hot water of expected demands. Yeah, if your tankless heater comes with a storage tank, it can manage the water demands to some extent in emergency cases.

types of tankless water heaters

Conclusion

This buying guide describes thoroughly all features of electric tankless hot water heaters.

Now, it is easier for you to choose the best tankless water heater to provide you in-line hot water, ideally fulfilling all your household demands of instant hot water.

FAQ

What is the best tankless water heater on the market?

The best tankless hot water heaters must have the following features to be best. They must have a maximum 6GPM. They must be energy star certified. As they are eco-friendly and energy efficient and almost save 50% on electric bills. 

Furthermore, robust materials like stainless steel and copper are used in manufacturing which increase durability and long lasting. 

The best tankless water heaters come with a convenient warranty. Some of the models of popular brands fulfill the above mentioned criteria. 

They are EcoSmart 27, Rinnai RL series, Stiebel Eltron Tempra series, and Rheem 240kw are some of them.

Is a tankless water heater worth it?

Tankless hot water heaters come with multiple benefits like they provide endless hot water for household demands but never run out of it when installed properly. 

They do not waste energy by heating and reheating water as the heat water instantly when it is required. 

They terminate standby loss. Being most energy efficient, they use less energy, only when hot water is required. Consumer reports state tankless heaters help you save $100 yearly as they are 22% more efficient than conventional tanks. 

Surprisingly, tankless water heaters are slim and compact design with wall-mounting features does not require huge space to be placed. They fit easily anywhere on the wall in the house.

Also, they are available in electric or gas models. So, choose wisely which is in your budget. They are robust and decent warranties. With regular maintenance, they can run up to 20 years.

Damage parts are easily available and replaceable. 

What is the downside of a tankless water heater?

Sadly, the instant hot water heaters have some disadvantages too. For instance, they have limited flow rate. If you need multiple water applications with instant hot waters at the same time, you will face low flow rate or even cold water accidently. Unless you install either a whole house tankless heater system or many point-of-use water heaters to each faucet. And definitely this solution is costly.

An on demand water heater is three times more expensive than their traditional counterpart. You have to spend sufficiently on electric upgrades in case of electric tankless heaters. 

Not only gas tankless heaters are expensive but their initial cost is also high. As you spend a huge amount on installation and venting. 

If your location has hard water, then water softener installation is a must to run the tankless heater properly. Otherwise, tankless water heater will die soon. Regular maintenance is compulsory for the longer life span of a water heater.

What size tankless water heater do I need for a family of 5?

The family with 5 people has high demand for instant hot water. As many household tasks like hand washing, dish washing, hot showers,  and laundry might be carried out simultaneously. 

So, it would not be a wrong estimation if we say that 10 GPM is the considerable flow rate for the family with five persons. And the incoming water temperature is low. 

And 7 GPM is adequate for this family if inlet water temperature is high. 

How long does a tankless water heater last?

Fortunately tankless heaters last long. But their long life is dependent on various factors which are regular maintenance, decent usage and incoming water quality. 

Tankless water heaters last about 20 years, whereas storage tanks have a shorter life span, generally 8 to 12 years. 

They are robust and mage with stainless steel which is corrosion resistant. Further, their parts are easily available and can be replaced easily. These features also extend their life span.

Daniel Adley is an experienced and skillful plumber having more than 20 years of experience. He is a skillful plumber who passionately repaired and optimized water appliances of large buildings, offices and homes. He would efficiently identify plumbing and maintenance issues.

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