Best Tankless Water Heater for Home Energy Saving

Tim Parry


Having hot water in your home taps is a great necessity that might come at a hefty price if you are using a reservoir water heater. Alternatively, you can switch to tankless water heaters that will provide you with an on-demand supply of hot water. Accordingly, you will need to get the best tankless water heater for every point you need instantaneous hot water.

What Brand Of Tankless Water Heater Is Best?

In that case, we have compiled a detailed buying guide for quality tankless water heaters in the market today. Nonetheless, let's first understand what a tankless water heater is.

What is a Tankless Water Heater?

A tankless water heater is a plumbing unit that heats water on demand as it flows and doesn't have a water reservoir but retains water in its heat exchanger coil. This heater type can be installed in multiple use-points around a household without a central heating system.

Due to its on-demand application, it is an excellent power saver regardless of the energy or fuel type consumed. This type of water heater also comes in compact models that can be easily fitted in tight spaces, saving on space. However, most manufacturers recommend the installation services from professionals or their recommended dealers.

Having understood the concept of a tankless water heater, let's get into the reviews of the five best products in this category. We will also highlight light their respective pros and cons.

1. Bosch Electric Mini-Tank Water Heater

Bosch Electric Mini-Tank Water Heater Tronic 3000 T 4-Gallon (ES4) -...
  • CONVENIENT HOT WATER HEATER: 4 gallon point-of-use mini-tank fits...
  • LONG LASTING QUALITY: This electric water heater is easy to maintain...
  • INDEPENDENT INSTALLATION: 36-37" cord plugs into a 120 volt outlet for...
  • FAST RECOVERY RATE: Eliminates long waits for hot water at your sink,...
  • EASILY MOUNTED: Can be shelf, wall or floor mounted (bracket...

Our first recommendation for the best tankless water heater is the Bosch Electric Mini-Tank model. This POU heating unit is ideal for application under a sink, shower, and supplemental roles to a central heating system. In addition, its instant water heating characteristic makes it rank among the best electric water heaters with the option of an additional mini-tank for a reliable hot water supply.

Additionally, it is built with a consistent 98% thermal efficiency and can simultaneously supply hot water to two sinks. This tankless heater can also be mounted on the floor or wall, depending on the location of hot water outlets. Eventually, this Bosch tankless heater can heat water faster with a long utility life.

  • Easy installation with an easy plug-in system
  • Faster water heating within 30 seconds
  • It can feed two sinks at a go due to its high thermal efficiency
  • Ease of maintenance and durable glass-lined material.
  • Authorized dealer installation needed for warranty recovery

2. EcoSmart ECO 27 Tankless Water Heater

Ecosmart ECO Electric Tankless Water Heater, 27 KW at 240 Volts, 112.5...
  • Endless on-Demand Hot Water; Consistent hot water when you need it...
  • Save Space; EcoSmart tankless electric water heaters are 90% smaller...
  • Save Energy; EcoSmart tankless electric water heaters are 99% thermal...
  • EcoSmart ECO 27 Sizing; Refer to the sizing map. Requires 3x40 AMP...
  • Warranty and Certifications; Limited Lifetime Warranty on electronics,...

Another incredible choice among the best tankless water heaters is the EcoSmart ECO 27 Tankless Heater. This heater is also an electric model applicable as a POU unit, suitable for an average-size or small household. Furthermore, this heater is energy efficient with an efficiency rating of 99.8%. The self-modulating technology also boosts the energy efficiency of this heater by adjusting the heating energy according to the specific water flow.

Regarding its flow rate, this heater has a 6.6 GPM with an adequate temperature rise of 430fahrenheit. Consequently, you can install this tankless unit in larger households with warm water and smaller homes with cold water. It is compact and can be easily mounted on walls and floors to save on space. You can also cut installation costs and ensure you use professional installation services. The reason for a professional installer is to maximize its lifetime warranty for its heating elements.

  • Enhanced flow rate for either warm or cold climates
  • Durable stainless steel and copper components
  • Easy to install
  • Enhanced power efficiency
  • Saves space
  • Digital temperature control dial for 1temperature increments
  • Complicated warranty recovery due to the professional installation requirement

3. Stiebel Eltron Electric Tankless Water Heater

Stiebel Eltron Tankless Water Heater – Tempra 24 Plus – Electric,...
  • CONTINUOUS FLOW – Advanced Flow Control patented technology invented...
  • SPACE & ENERGY SAVER – Its small, sleek white design saves space yet...
  • EASY OPERATION – Electronic switch activates the hot water heater...
  • TEMPRA 24 PLUS – This specific model is 24kW, 240V, requires a min...
  • WARRANTIES INCLUDED – Stiebel Eltron’s top-rated electric tankless...

We also recommend the tankless electric heater from the Stiebel Eltron brand. This German-made tankless features excellent instantaneous water heating with a flow rate of 4.0 GPM. Moreover, it is built with advanced flow control for maintaining constant hot water temperature during higher flow rates. Consequently, this tankless electric unit is ideal for small households.

When it comes to its temperature rise capacity, it features a 430 Fahrenheit with a 99% energy efficiency rating. However, this heater has a higher price tag because of its convenient design and digital controls, making it suitable for tight and hidden spaces. Eventually, this model is one of the best tankless water heaters for electric energy as enabled by its Tempra Plus 24 energy efficiency technology.

  • Incredible power efficiency with the extra Tempra plus 24 technology
  • Ease to use through its digital controls
  • Compact for saving space
  • Consistent supply of on-demand hot water
  • Quiet operation
  • Excellent adjustment to temperature changes
  • Ideal only for small households
  • Expensive for an electric heater

4. Rheem 240V Tankless Water Heater

Rheem 240V Heating Chamber RTEX-13 Residential Tankless Water Heater,...
  • External adjustable digital thermostatic control with LED display (+/1...
  • Durable Copper immersion two heating elements, field...
  • Simple installation – 1/2 NPT adapters included; side 1/2 inch...
  • 99.8% energy efficient. External controls to adjust temperature in...
  • Threaded for easy replacement, simple installation, digital...

Among the quality tankless electric units, we also recommend the Rheem 240V Tankless Water Heater. This water heating unit is built with a beautiful aesthetic of an LED display and a digital adjustable thermostat for easy operation. Furthermore, it is highly energy-efficient with an extra 99.8% efficiency rating than other conventional tankless electric units. Its energy efficiency is also enhanced through its self-modulating technology that detects the water flow and adjusts power appropriately.

Moreover, its ease of installation is enabled through its NPT adapters with the manufacturer's installation instructions. You can also enjoy an incredible flow rate of 3.17 GPM with two copper-immersed heating elements. Its LED screen provides for temperature displays with accuracy levels of up to + or -10.

  • Easy to install
  • Energy efficient with an adequate flow rate of 3.17 GPM
  • Easy to use with its digital controls and LED display
  • Ideal for multiple or point-of-use application
  • An excellent temperature rise of up to 1400degrees
  • Possible inaccurate temperature increments if the heater runs for long

5. Titan SCR2 N-120 Tankless Water Heater

Last on our list is the Titan SCR2 N-120 tankless heater. This unit ranks among the best tankless water heaters because of its quick water heating with a high-efficiency rating. It is also built with a digital control panel for easy use and beautiful aesthetics to a user. If you settle for this product, you will enjoy increased durability, unlike other similar units in the market due to its super-sturdy build.

As an economical electric candidate, this heater can meet the hot water demands of an averagely small household. You should also avoid running multiple taps using one unit of this model.

  • Digital controls for easy use
  • Relatively faster water heating depending on the placement of this unit
  • Saves space and power
  • Sturdy build for improved durability
  • Risk of temperature inaccuracies due to multiple tap application

Tankless vs. Tank Water Heaters

Firstly, a tankless option provides better energy efficiency than the reservoir water heater at an estimated 24% to 34% increased efficiency. The reason for this is because tankless heaters work on a need basis while the reservoir water constantly runs to keep stored water hot. Additionally, the tankless heaters are smaller and less bulky than the reservoir water heaters. When it comes to durability, a tankless heater is expected to outlive the reservoir water heater, with an estimated 20 years and 15 years maximum, respectively.

Nonetheless, tankless heating units are more expensive than their tank counterparts. Moreover, the installation expenses of tankless units are more expensive than that of tank units. Regarding the reliability of constantly heated water, a traditional tank heater is more reliable than a tankless unit which might be affected by lower temperatures. Overall, you can consider these characteristics while choosing between a tank or tankless heating option for your home water.

Types of Tankless Water Heating Systems

1. Non-condensing

The first tankless heater generation applies the non-condensing heating system. This process uses a heat exchanger for dispensing hot water on a need basis. The non-condensing type has an estimated EF rating between .82 and .85, which is an estimated $75 to $80 energy savings annually. Another primary advantage of this system is that heaters in this category are cheaper and less bulky than their condensing counterparts.

However, this type has the disadvantage of heat emissions for gas or propane, needing the installation of an expensive stainless steel exhaust system. In addition, it might not be energy efficient for constant short draws.

2. Condensing

Secondly, there is the condensing heating system that applies an additional heat exchanger for eliminating emitted heat by the water further. The additional water heating provides an increased efficiency rating between .92 and .94, which is around an estimated $90 to $100 in annual power savings. Moreover, the condensing tankless water heaters require less expensive PVC venting systems. However, due to the extra fitted heat exchanger, they are bulkier and more expensive.

3. Point of Use (POU)

Without a storage tank, you can also use a Point of Use (POU) heating system. The POU works to eliminate the loss of heat within a hot water supply system. Precisely, water in this system is heated at the closest possible point to an outlet, such as in a shower, sink, or bath. This heating system is different from a central reservoir heater installed for hot water supply in the whole house.

POU works for individual designated hot water outlets with an improved power efficiency due to its need basis application. However, despite the power efficiency, there is the cost disadvantage of installing multiple POU heaters at different water points in a large home.

Factors to Consider Before Buying the Best Tankless Water Heater

1. Flow Rate Capability

Matching the water flow rate in your house in terms of gallons per minute (GPM) with a tankless water heater is important for the optimal benefits of a tankless unit. Every tankless hot water unit's individual gallons per minute (GPM) specifications should be applied for durability and reduced replacement costs. Accordingly, the larger the home size, the more hot water on demand, needing a tankless model with a higher flow rate.

2. Energy or Fuel Type

Also, while buying a tankless water heater, consider the type of energy it uses to heat water. Essentially, three energy types are utilized in various tankless water heaters, including propane, natural gas, and electricity. Below is a brief explanation for each energy type:

  • Propane tankless water heater. This type runs on piped home propane which must be replaced or refilled when empty. The propane tank replacement makes this tankless heater is impractical for home application, unlike the gas heater, which relies on piped gas supply.
  • Gas-powered tankless heater. A gas tankless water heater is cheaper than the propane option. Moreover, a gas-powered heating element is also ideal for a long-term heating plan and suits households that demand hot water on a large scale. Therefore, a natural gas tankless water heater is ideal for homes with piped natural gas but might not be practical for RVs. Considering that natural gas provides higher power outputs, it is better than the electric model for heating more water with more power savings.
  • Electric tankless water heater. Electric tankless water heaters are more affordable in terms of installation and initial acquisition. Moreover, tankless electric heaters feature high electricity consumption, making them an expensive power alternative due to the high electricity costs.

Bearing in mind the energy factor in this category, the best tankless water heater should match the existing energy plan in your home for easy and reduced installation expenses. Additionally, you should pick a power plan that will be manageable during sustenance and maintenance. Finally, regarding the durability of heaters, gas heaters have higher durability than electric tankless heaters.

3. Temperature Rise

When it comes to the temperature rise aspect, it refers to the temperature difference between the incoming water and the outlet desired hot water. Ideally, the colder the inlet water, the more heating a tankless model will have to do. Furthermore, this aspect of increasing temperatures works alongside the GPM factor. Subsequently, the more rise in temperatures needed, the lower the GPM will be for optimal heating to give you the desired water temperature.

4. EF Rating & Durability

Another factor to consider while buying the best tankless water heater is the power efficiency rating. The EF (energy factor) rating is an indicator of hot water produced per fuel consumption unit. A tankless heating element with a higher EF rating means less fuel consumption for effective water heating.

Specifically, Energy-Star products optimize power efficiency. In addition, you can also benefit from the power rebates offered to Energy-star units. Therefore, you should target to get an efficient unit with an excellent GPM.

5. Venting

A propane or gas tankless heater should also be equipped with an exhaust for burnt fuel fumes. In light of pets and people in your home, fuel fumes must be vented outside. However, ventilation adds to the installation expenses, making the two alternatives in this context impractical in contemporary homes. Nonetheless, this article provides you with electric options that feature easier installation without the hassle of a venting system.

Frequently Asked Questions on the Best Tankless Water Heater

1. Is it worth switching to tankless water heaters?

Yes is worthy and a smart move switching to tankless water heaters. Ideally, tankless heating units will save your energy, space, and installation expense. In addition, considering you only use them on-demand basis, they tend to be durable and power-efficient. First, however, you need to get the appropriate model with a GPM that suits your hot water needs and climate.

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Tim Parry

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