Best Tankless Gas Water Heater

Best Tankless Gas Water Heater for Every Household

Updated on

Brenda Nyawara

Brenda Nyawara is an editor at Archute. She is a graduate architect with a passion for edge-cutting ideas in design, fashion, art and modern world interests.
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According to the US Department of Energy, tankless water heaters boost energy efficiency by 24-34% compared to the regular water heater storage tank, which heats and stores gallons of hot water. Therefore, investing in the best tankless gas water heater will save you money. We have listed excellent options and the crucial considerations when buying an ideal for your home.

What is a Tankless Water Heater?

Tankless water heaters also referred to as instantaneous, on-demand, continuous flow, or instant-on water heaters. The products instantly heat water as it goes through the devices and retains no water inside them except for what is in the heat exchanger coil. Besides, they deliver a constant supply of hot water when it's required.

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These water heater models don't have the standby energy losses that storage water heaters have therefore saving money. Now that we know what a tankless device is, let's check out the best models for your home.

1. Rinnai Propane Tankless Water Heater, V65iP

Rinnai V65iP Propane Tankless Hot Water Heater, 6.5 GPM
  • Endless Hot Water: Enjoy unlimited hot water flow throughout the...
  • Energy and Space Efficient: Space-saving design conserves energy...
  • Optimal Water Pressure: High-performance up to 6.5 GPM hot water...
  • Enhanced scale detection lessens possibility of serious,...
  • Guaranteed to Last: 10-, 5-, and 1-year residential factory...

If you are looking for the best tankless water heater that you can use conveniently indoors and outdoors, we recommend the Rinnai V65iP model. It has a maximum input of 150,000 BTUs and hot water output of 6.5 GPM, making it ideal for a home with one or two bathrooms or one to two adults or teens.

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The unit features the Control-R 2.0 mobile app. The app is easy to use; I usually schedule hot water needs during the day. Also, when I'm not using the water heater, I usually use the app to put the unit in sleep mode.


  • Energy and space efficient
  • Ideal capacity for one or two adults
  • Offers optimal water pressure
  • Features the Control-R 2.0 mobile app, which is easy to use


  • It takes a few minutes to generate hot water.

2. Rinnai Natural Gas Tankless Hot Water Heater, V65eN

Rinnai V65eN Natural Gas Tankless Hot Water Heater, 6.5...
  • Endless Hot Water: Enjoy unlimited hot water flow throughout the...
  • Energy and Space Efficient: Space-saving design conserves energy...
  • Optimal Water Pressure: High-performance up to 6.5 GPM hot water...
  • Enhanced scale detection lessens possibility of serious,...
  • Guaranteed to Last: 10-, 5-, and 1-year residential factory...

Rinnai V65eN Natural Gas Water Heater has a flow rate of 6.5 GPM, which equates to continuous hot water for up to four fixtures. Conversely, a showerhead usually has an EPA-mandated flow rate of 2.5 GPM. Hence, I could hook it up to two showers, a sink, and a washing machine and have them operate simultaneously without experiencing hard temperature drops.

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This gas-powered tankless heater comes with a leak detection feature, which immediately turns off the water supply valve if a leak is detected. We love this tankless gas water heater's space-saving and energy consumption, saving 40% more energy than standard tanks.


  • Ideal for up to four fixtures
  • It comes with a leak detection feature
  • An energy and space efficient unit


  • Lack an individual faucet temperature setting.

3. Camplux (AY132) Enjoy Outdoor Life Propane Tankless Water Heater, 1.32 GPM

CAMPLUX ENJOY OUTDOOR LIFE 5L 1.32 GPM Outdoor Portable...
  • Compact,Portable Design: The compact portable water heater...
  • Installation Recommended: This propane water heater only takes...
  • Operation Features: The flow rate is 1.32 GPM, 1.32 gallons of...
  • Wide Applications: The water heater start up with 3.0 PSI lowest...
  • 6-in-1 Proection: Flame failure device, anti-freezing protection...

If you want the best tankless gas water heater for outdoor uses, count on the Camplux AY132 Propane Tankless Water Heater. You can use this unit for almost anything from taking outdoor showers to bathing your dog. Though it only has a 1.32 GPM output, you can conveniently use and install it in cabins without needing a messy gas hardline.

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I usually carry my Camplux AY132 Tankless Water Heater if I intend to go camping for more than one day. The fact that it comes with a folding handle makes it convenient to carry around. Another impressive feature of this unit is that it comes with a max dual regulator, which allows flow rates to be set from 46.4°F to 114°F temperature. You will love this feature, too, if you are sensitive to higher or lower water temperatures.

Furthermore, the water heater's igniter requires two D-cell batteries, or you can plug it into a standard outlet. Besides, you can pair it with a 12-volt water pump to boost water pressure.


  • It comes in a budget-friendly price
  • Perfect for camping
  • Compact and portable unit
  • Easy to operate


  • 1.32 GPM output is quite low

4. Eccotemp Tankless Hot Water Heater, i12-NG

Rinnai RL75IN Tankless Hot Water Heater, 7.5 GPM,...
  • Energy and Space Efficient: Space-saving design conserves energy...
  • Optimal Water Pressure: High-performance 7.5 GPM hot water flow...
  • Instant Heating: Circ-Logic technology enables recirculation...
  • Guaranteed to Last: 12-, 5-, and 1-year residential and 5-, 5-,...

Eccotemp i12-NG Natural Gas Tankless Water Heater has a flow rate of 3GPM, which is enough to let me operate a shower and a faucet at the same time. Moreover, it has a consistent temperature rise, with a 35-40° temperature rise at 3 GPM and a 77° temperature rise at 1.5 GPM. Also, the unit is compact, taking very little space on a tabletop or wall.

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Furthermore, the tankless water heater has Concentric and PVC venting options. Additionally, I like that the unit is easy to install and energy efficient too. Plus, the model has childproof, alongside a UL-listed child-lock technology for preventing unattended use. Hence, I was more relaxed that kids could not tamper with it.


  • It comes with an LED display
  • Features child safety lock
  • The unit has an automatic temperature control
  • Easy to install and energy efficient


  • 3 GPM output is low

5. Rinnai RL75IN Natural Gas Tankless Hot Water Heater, 7.5 GPM

Eccotemp i12-NG Tankless Water Heater
  • Whole home indoor, gas powered tankless water heater, rated at 3...
  • Sleek, modern design with black tempered glass front panel...
  • Features fully automatic temperature controls with an energy...
  • Safe electronic ignition system; Plugs into standard 110v...
  • Uses standard 1/2" NPT water fittings and comes with horizontal...

Rinnai RL75i Tankless Gas Water Heater offers up to 7.5 GPM of hot water and can conveniently support up to four different fixtures simultaneously, depending on the groundwater temperature. Besides, the unit has a maximum output of 180,000 BTUs, making it ideal for houses with two bathrooms and less than three adults or teens.

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This unit has Rinnai's ThermaCirc360 technology, which helps it provide consistently hot water when the faucet is turned on. Also, I love that the unit features leak detection technology, which immediately turns off the water supply valve if it spots a leak.


  • Offers faster flow rate
  • You can use it in mobile homes
  • Conveniently support up to four different fixtures at the same time
  • The unit has an automatic temperature control


  • It is a bit expensive.

Factors to Consider Before Buying the Best Tankless Water Heater

1. Intended Use

Where do you plan to use your tankless gas water heater? Depending on the setup location, you can go for a whole-house tankless water heater or a point-of-use water heater. But of course, the former is more powerful than the latter.

Furthermore, whole-house tankless heaters provide enough hot water for an entire residence and have significantly larger flow rates and power inputs. On the other hand, point-of-use models are designed for use on a single fixture, with enough flow and power to heat water for one shower or sink.

2. Fuel Type

Before buying the best gas tankless water heaters, consider the fuel type. There are two types of gas fuel for these models; natural gas and propane gas. You can also get an electric tankless water heater. Let's go into detail on these types of fuels.

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i) Propane Gas 

It is the most expensive fuel option and is often not piped into residential homes. Therefore, it's more likely you will require a fuel tank for the water heater, which will take up space saved by the tankless design. However, propane tankless water heaters offer the best energy production, even outperforming natural gas. Also, they are ideal for recreational vehicles because of their liquid propane portability.

ii) Natural Gas

It is less expensive than propane gas and electricity. Besides, it's best for long-term investment due to the lower cost of natural gas, which will eventually pay for the unit. Also, natural gas is an excellent option for high-demand families.

However, natural gas is not easy to store. Also, we wouldn't recommend using it in an RV or at a campsite. Moreover, keep in mind that your home might not have natural gas connections, and if this is the case, extending a line into your house will raise the installation fee.

iii) Electric

Tankless electric water heaters are the least expensive option for initial purchase and installation. However, the high electrical requirements and lower total power production can quickly add up. One thing to remember about electric models is that their efficiency rating is about 10% higher than that of gas ones. Consequently, you can save more energy than with a gas model.

Conversely, depending on the current price of electricity vs. gas in your location, it may cost more. In addition, electric tankless water heaters have significant power requirements that an older home may not meet. Therefore, if the current electrical system doesn't meet the manufacturer's requirements, you will need a different water heater or pay more to upgrade the electrical system.

3. Flow Rate

Before getting the best tankless gas water heater, consider the flow rate, usually measured in gallons per minute (GPM). The manufacturer lists the measurements, which you can establish the maximum flow of hot water the heater can generate. Besides, each fixture in the house will consume a fraction of the water heater's total flow rate.

 For example, a sink uses roughly 1.5 GPM on average, whereas a shower requires about 3 GPM. Therefore, to operate both the sink and the shower at full capacity, the tankless water heater must have a flow rate of at least 4.5 GPM.

Conversely, households with more than four adults should invest in tankless water heaters with a flow rate of 7 to 8 GPM, while those with three or fewer adults should be fine with a flow rate of 3.5 to 5 GPM.

4. Condensing vs. Non-Condensing

i). Condensing

These tankless water heaters come with a condensing unit that absorbs and reuses the remaining exhaust heat before discharging a considerably cooler exhaust via the ventilation channels to the outside. Though this type is more expensive, it saves on ventilation material and achieves 98% efficiency.

iI). Non-Condensing

This type of tankless water heater will instantly exhaust the steam; therefore, ventilation materials must be able to tolerate high temperatures when hot steam passes through the their channels. Besides, these high-quality materials are expensive, and installation costs can be high.

The heat lost due to the quick venting of this steam results in an efficiency rating of around 80-85%. However, this type of water heater is less expensive to buy.

5. Safety Features

Before buying the best tankless gas water heater, it's wise to check for safety features. Keep in mind not all manufacturers make their tankless gas water heaters with safety features. In addition, you want protection from freezing and overheating if the unit is to be installed outsides or in a less ventilated area.

Some gas tankless hot water heaters have an automatic shutoff feature that usually shuts down the unit if there is excess water pressure or when it runs out of water. Besides, if you install the water heater in the open and have kids, a child safety lock feature on the controls will prevent accidents.

Frequently Asked Questions on the Best Tankless Gas Water Heater

1. What size gas tankless water heater do I require for a two-bathroom house?

As a general rule, the minimum size should be a 5 GPM flow rate for a two-bathroom house. For larger households, we recommend a 6 GPM flow rate or higher.

2. How do you install gas tankless water heaters?

Installation of a tankless gas water heater requires a professional plumber since a gas line needs to be safely connected to the unit and tested to confirm the connection does not leak fuel.

3. What are the cons of a tankless water heater?

The main setback of tankless water heaters is that they're substantially more expensive to buy (unit and installation) than tank-style heaters. On average, tankless water heaters cost three times as much as tank-style water heaters, including installation.

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About the author

Brenda Nyawara

Brenda Nyawara is an editor at Archute. She is a graduate architect with a passion for edge-cutting ideas in design, fashion, art and modern world interests.
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