Best Tankless Water Heater Reviews 2017-10-31T15:57:29+00:00

What is a tankless water heater?

A tankless water heater is a water heater that provides hot water only when needed. It does not use a storage tank to heat water 24 hours a day. This on demand heating is accomplished by using a heating element to heat the water immediately as it passes through the unit.

A “point of use” water heater is a small tankless heater and is an alternative to a centrally located tankless water heater. This point of use, a.k.a. on demand water heater, is located near a sink, shower or bath. Without the need for a storage tank, the water heater is small enough to fit under the sink or inside a linen closet. Point of use water heaters are a great choice for single bathrooms located far from a conventional storage tank heater. If needed, several point of use units can be used in multiple locations throughout a home.

As previously mentioned, there are also larger, whole house tankless water heater models which are centrally located and provide hot water usage for the entire home.

How do these models work?

On demand water heaters have flow sensors which activate as water enters into the unit as the hot water tap is turned on. Once water enters into the unit, it crosses a hot coil exchanger that is warmed by gas or electricity resulting in a continuous supply of hot water. No hot water storage tank is necessary.

  • Save Money

  • Save Water

  • Save Energy

  • Save Space

What are the benefits of owning a tankless water heater?

  • Decreased energy demand resulting in lowered yearly cost – it produces hot water only when you need it, rather than heating water at 3am while people are sleeping.
  • Very little water waste- no more wasting gallons of water while waiting for the shower or sink to heat up.
  • Tax credit/rebates are available

Will you save money by using a tankless water heater?

Yes, but not initially. The cost of installation is higher than the conventional storage water tank heater, but you will see the most value reflected in means of savings on your water, gas and electric bills.

The American Council for an Energy Efficient Economy states that a tankless system can lower energy consumption by 10-15% and the U.S. Department of Energy states that tankless heaters overall are worth the investment since they use less fuel in average households. Owners can make the most of their savings by also installing low flow showerheads.

To summarize: Over the long term there is a great amount of savings in store for the home owner, whether it be savings in gas, electricity, water, space, money or the environment.

How long do they last?

The life expectancy of most top rated tankless water heaters is more than 20 years, plus you can get away with extending their life by easily replacing parts. Additionally, most companies offer a warranty to back their product.

Do you get a tax rebate/credit?

Point of use water heaters must have a minimum energy factor of 0.82 or minimum thermal efficiency of 0.90 to qualify for a $300 US Federal Tax Credit. The unit needs to be installed in a primary residence owned by the taxpayer. Use IRS Form 5695 when filing your taxes but they recommend you consult with a tax professional to confirm all requirements are met.

What size tankless water heater do I need?

Tankless water heaters use the term GPM the average flow rate in gallons per minute. The GPM is used to estimate hot water usage, so it may be helpful for you to know some average figures of estimated water demand in your home before making a purchase. One of the best ways to determine the right size tankless water heater that will be needed is by shower usage. The average shower lasts eight minutes and uses between 24 to 30 gallons of water. The average temperature most people prefer is 105 degrees Fahrenheit. Once the shower usage is determined, you will need to figure if simultaneous showers are likely. Then take into consideration the following estimates:

Shower – 4 GPM

Washing machine – 3.3 GPM

Kitchen and bathroom sink – 2.2 GPM

Dishwasher – 1.3 GPM

Next, determine the average ground temperature of your incoming water during the colder months. Subtract this number from the maximum water temperature of the tankless water heater you are considering to establish your specific need.

What is the best tankless water heater brand?

The following will give tankless hot water heater reviews & a summary of information about the leading tankless water heater brands on the market.

Navien Tankless Water Heater Reviews

The Navien tankless water heater  NPE 240A is a whole house unit. It is a  ultra condensing tankless water heater which uses a dual stainless steel heat exchanger with comfort flow technology to regulate the temperature. This Navien NPE unit utilizes your existing 1/2 inch gas line and uses 2” PVC venting. It also has easy field gas convertibility from NG to LP operation. The 11.2 gallons per minute gpm is a high flow rate that can easily accommodate two showers.

Additionally, this is the first unit that incorporates ComfortFlow, an internal circulation with buffer tank that can eliminate the “cold water sandwich” effect. For the Navien tankless water heater price click below.

The rundown on the Navien NPE:

  • Natural gas / propane
  • stainless steel exchanger
  • 120 volt
  • Low NOx
  • 35 degree rise = 11.2 GPM °
  • 67 degree rise = 5.6 GPM
  • 0.96 NG or 0.96 LP
  • Warranty: 15 year exchanger, 5 year parts, 1 year labor

Ecosmart Tankless Water Heater Reviews 

The ecosmart tankless water heater  ECO 27 is one of Ecosmart’s top tankless water heaters model. With it’s self-modulating technology it will adjust its energy usage to how much water is needed resulting in up to 50% saving on water heating costs. ECO 27 has both copper and stainless components which provide energy efficiency, durability and are easily replaced. This compact model is energy efficient and stylish and will save valuable storage space.

The rundown on the Ecosmart ECO:

  • Electric
  • copper exchanger
  • 240 volts
  • ECO27 35 degree rise = 4.9 GPM   / 65 degree rise = 2.7 GPM
  • ECO36 35 degree rise = 6.5 GPM  /  65 degree rise = 3.6 GPM
  • Warranty: Lifetime

Rinnai Tankless Water Heater Reviews 

In our rinnai water heater review, the R75LSi was determined to be the best of their models on the market. The Rinnai R75LSi delivers a high flow rate up to 7.5 GPM which is ideal for up to two or three bathrooms home and has the convenience of both concentric and PVC/CPVC venting in the same model. By using the appropriate fittings, buyers can choose to vent through the wall or roof. Rinnai’s ThermaCirc360 uses thermal bypass technology, an internal bypass line with a thermal bypass valve. The ThermaCirc360 helps create immediate hot water availability even in the coldest climates.

The rundown:

  • Natural gas / propane
  • Low NOx
  • 35 degree rise = 7.5 GPM
  • 65 degree rise = 4.9 GPM
  • Energy Star rated w/ 0.81 ng / 0.81 lp
  • Warranty: 12 year exchanger, 5 year parts, 1 year labor

  Rheem RTEX-13 Tankless Water Heater Reviews

The Rheem RTEX13 tankless is one of our top rated electric water heaters. Its external controls allow you to adjust the temperature by 1°F reaching up to 6 GPM for the whole house. This stylish model is efficient and easy to install and is rating four stars for best pricethe company has to offer.

Rheem Tankless Water Heater Reviews 

The Rheem has three series of tankless water heaters: the prestige series, the classic series, and their mid-efficiency series. RTG-64XLN is a natural gas outdoor tankless water heater that is in their mid-efficiency series. It produces the flow rate of 6.8 GPM at a 35A degree Fahrenheit maximum rise and 5.3 GPM at a 45A degree Fahrenheit max rise. Since this unit uses gas and is kept outdoors, it is not well suited for cold climates. The 0.82 EF unit has an all copper heat exchanger with an overheat film wrap (OFW) to protect the heat exchanger. This one also comes with a digital remote control, a 10 ft. thermostat wire, and a manual gas isolation valve. Even though the RTG-64XLN is the heater recommended, the Rheem RTE model is one you may also want to take a look at.

The rundown:

  • Natural gas
  • copper exchanger
  • 0.82 Efficiency factor
  • 35 degree rise = 6.4 GPM
  • 65 degree rise = 4.5 GPM
  • Warranty: 12 year exchanger, 5 year parts, 1 year labor

Noritz Tankless Water Heater Reviews 

The Noritz tankless water heater has two units that are worth mentioning. The NRC661-DV-NG and the NR981-SV-LP.

The NRC661-DV-NG has a flow rate capacity up to 6.6 GPM. It can be wall-mounted indoors or outdoors (which would not require ventilation if outdoors). The Direct Vent model can be converted to a non-direct vent model by using a Conversion kit (#SV-CK-3). This model has an energy factor or 0.91 (NG) or 0.93 (LP) and is fully condensing, 93% efficient for use with natural gas or propane.

The NR981-SV-LP model has a flow rate up to 9.8 GPM. With the installation, you have the option to mount indoors or outdoors. Its steel casing with polymer coating  and commercial grade copper heating exchange makes this model extremely durable with great performance. This heater has an energy factor of 0.82 (NG) and 0.88 (LP) and is 84% efficient for use with natural gas or propane.

The rundown:


  • Natural gas / propane
  • Commercial grade copper
  • Low NOx
  • 35 degree rise = 6.0 GPM (approximated)
  • 65 degree rise = 3.5 GPM (approximated)
  • 0.95 ng / 0.96 lp
  • Warranty: 12 years exchanger, 5 years parts, 1 year labor


  • Natural gas / propane
  • Commercial grade copper
  • Low NOx
  • 35 degree rise =
  • 65 degree rise =
  • 0.82 ng / 0.88 lp
  • Warranty: same as above model

Marey Tankless Water Heater Reviews 

The Marey tankless water heater ECO line is designed with SMART technology to prevent an accumulation of sediment forming on the element. These ECO units do not allow the water to touch the heating element decreasing chlorine and calcium buildup. It will increase the water temperature by 28 degrees Fahrenheit at 3.0 GPM or 56 degrees Fahrenheit at 1.5 GPM. It performs best in regions where the incoming water temperature is above 70 degrees F (warmer climates) and should not be installed no more than 40 feet from its intended point of use. The ECO tankless water heater  is a great choice for a small bathroom or to use as a single shower water heater.

The rundown:

  • small electric
  • 220 volt
  • 35 degree rise = 2.2 GPM (approximated)
  • 65 degree rise = 1.25 GPM
  • Warranty: 1 year parts and labor

Steibel Eltron Tankless Water Heater Reviews

Steibel eltron is a pioneer with over 90 years in tankless water heating technology and has produced one of the best rated tankless water heater models. The powerful Tempra Plus whole house electric tankless water heater has Advanced Flow Control enabling it to maintain a steady temperature even if flow rates vary. Unlike other manufacturers that will deliver colder water when pressure increases, the Tempra Plus uses the power of smart microprocessor technology to automatically reduce the flow of water slightly but at the correct temperature. A copper heating element and electric conductor is used to reach a max temp of 109 degrees Fahrenheit.

The Tempra Plus models range from 12 kW to 36 kW but we reviewed the Tempra 24 Plus. This unit can increase the water temperature by 37 degrees Fahrenheit at 4.5 GPM, and because it uses electricity rather than gas, there is no need for a vent which makes installation cheaper. Steibel Eltron may have created the best tankless hot water heater.

The rundown:

  • Electric
  • 240 volts
  • copper exchanger
  • 35 degree rise = 4.5 GPM
  • 65 degree rise = 2.5 GPM
  • Warranty: 3 year limited warranty

Takagi tankless water heater reviews 

Takagi water heaters are units you have to vent outside your home. This 110v tankless water heater is also in the best picks for tankless gas water heater reviews. For people who live in warmer regions, the gas model may be the right option for you. Buyers may also want to consider, for best pricethis small model the Takagi TKJR2 in NG.

The takagi tk4

Takagi t kjr2 in ng

Which small demand, point of use water heaters are recommended?

Bosch Tankless Water Heater Reviews 

For folks who do not have a need for larger whole house units, you could probably get away with using the Bosch Powerstar. This heater will only have to use 9.5kW of power to get what you need. The AE 125 powerstar electric tankless water heater uses a copper wire heating element and it requires a 40AMP breaker at 240V. So this unit itself is great to heat a sink in your home, but if you are looking for an rv tankless water heater, then the ecotemp may be a better option for you.

Bosch also makes the WH27 Tronic and US7 Tronic for entire homes, but for the price they did not make the cut in the best rated water heaters.

Eccotemp I10 or Eccotemp L5

Eccotemp is an excellent choice if you are looking to use for the convenience of a portable hot water shower or rv tankless water heater. The eccotemp produces a flow rate of 1.5 GPM of up to 150 degrees Fahrenheit of hot water using liquid propane fuel and a 2D cell battery. This propane tankless water heater has an automatic shut off over the 20 minutes and at only 13lbs, it is easily portable. This may be the best on demand water heater and is perfect for your portable hot shower.

Now that you’ve decided on either the best tankless gas water heater or the best electric tankless water heater, you’ll need to decide on the right method of installation.


Proper installation depends on fuel type, climate, and building code requirements. It is best to have a qualified plumber and heating contractor install your tankless water heater. When selecting a contractor, we recommend:

  • requesting a cost estimate in writing
  • checking with the local BBB
  • asking for references

If you think you are going to install the unit yourself, it is best to consult the manufacturer for appropriate installation and instruction manuals.

Tankless water heater maintenance


GPM – gallons per minute

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