Best Gas Tankless Water Heaters in 2022

Last Updated on 1 year by Todd

There are many water heaters on the market these days, but not all of them are created equal. If you’re in the market for a new one, it can be tough to decide which one is right for you. If you’re looking for a gas tankless water heater, we’ve got you covered. We’ve compiled some of the best gas tankless water heater reviews to help make your decision easier.

Gas tankless water heaters are a great way to save money and reduce your carbon footprint. They offer a faster flow of hot water, which is an excellent solution for large families that need more than one shower at the same time. In this blog post, we will look at the best gas tankless water heater options on the market today.

Natural gas-powered tankless water heaters are a good idea because you can get hot water at a lower cost and with less hassle. They will also be an excellent decision for most households for their hot water needs.

Before You Buy a Tankless Water Heater

A tankless water heater is being hailed as the most efficient way to heat your home’s hot-water. It doesn’t waste energy heating water that will be used up within an hour or two, which means it uses about half as much energy as a conventional storage tank does. In addition, you can save even more money on energy bills by using a timer to make sure the unit runs only when you need it. But there are still some things consumers need to consider before buying.

A tankless heater costs more than a traditional heater. The price range is between $1,000 and $3,000. When you include installation costs, the price can go as high as $6,000. For a traditional storage-tank model unit, the installation cost is between $1,000 and $2000.

Another virtal factor to consider is how much hot water your family uses each day. A tankless model may struggle to supply enough hot water if it’s required to serve multiple showers, a clothes washer, and a dishwasher at the same time.

There are few companies better than Plumbing-Heating-Cooling. For the most part, the installation process is straightforward and straightforward, so you don’t need to worry about that portion of it. However, there are some instances where special attention has to be paid to ensure the proper function of your tankless water heater system.

What to Consider When Buying a Tankless Water Heater

Quick access to hot water and reduced energy consumption are benefits of a tankless water heater. To choose the best one, think about what features would be best for your home.

Fuel Type

There are three main types of fuel for tankless water heaters. Gas models work better than electric ones because they heat the water quicker and more evenly. The downside is that it costs about $1000 more than an electric one. It takes longer to install too.

Natural gas usually costs less than propane or electricity. A tankless water heater is a good investment because the cost of natural gas is less than other things.

Natural gas is a good choice for homes that need to use a lot of energy and do not store other sources. If you live in an RV and want to use natural gas, this is not a good option. And if your home does not have an existing natural gas line, it will be expensive.

  • Propane gas Piping into a home is typically impossible because it is the most costly and, in many situations, cannot be done. A portable propane tank fills a tankless water heater that uses propane as its fuel. When the tank is empty, propane-powered tankless water heaters are difficult to use in homes but ideal for leisure vehicles.

Electric tankless water heaters are a good choice because they are easy to buy and install. They can be pricey, but then again, so is electricity.

Electrical models also have higher power requirements than many older homes can meet. If the current electrical system does not meet the manufacturer’s specifications, a costly upgrade to the electrical system could be necessary.

Flow Rate (GPM)

A tankless water heater’s flow rate is how much water it can produce. The more people who use the hot water, the more gallons per minute it will produce. The kitchen sink and bathroom tub require different amounts of flow rates.

Homes with more than 4 adults should have water heaters with a flow rate of 7.5 to 8 gallons per minute. Homes with less than 4 people can get away with the water heater’s flow rate being 3 to 5 gallons per minute.

When you figure out how much water is used in your home, think about the number of people and the number of things that need water. If there are not many people or big things, less water needs to go through the pipes. However, if numerous showers, a dishwasher, and a few sinks are likely to run simultaneously, a lower flow rate will be insufficient.

Power Input (BTU)

To heat water, you need energy. This is measured in BTUs. A BTU is an energy needed to raise one pound of water by one degree Fahrenheit.

You need to think about how much hot water you want when plugging in the tankless heater. If the water coming into your house is 40 degrees, and you want it to be 120 degrees in your shower, you need a lot of power.

The tankless water heater would need to increase the temperature by 80 degrees. To do so, it would need 667 BTUs per gallon. A shower operates at 2.5 gallons per minute or 150 gallons per hour. If a tankless water heater is used to heat 150 gallons of 40°F water to a temperature of 120°F, it will need to generate 100,000 BTUs every hour, with 100% efficiency and a single fixture in use. The minimum BTU requirement goes up if the efficiency level falls or another fixture is used.

The basic formula is:

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

Efficiency Percentage

Where 500 (or 499.8 rounded up) is the weight of a gallon of water (8.33 lbs) multiplied by 60 minutes.

To know how many BTUs your home needs, do this math.


Gas tanks do not need to be connected to the house, so exhaust does not come in. Ventilation pipes cost more and can increase the price of a water heater.

Condensing vs. Non-condensing

Steam is a byproduct of the gas in a tankless water heater. When you turn on your tankless water heater, the steam comes out of the vent for a little bit and then goes into the air outside. A condensing or non-condensing tankless water heater does this at different times.

Non-condensing tankless water heaters vent the steam immediately. This means that they need to use materials that can withstand high temperatures. These materials are more expensive, which means installation is more expensive too. But the non-condensing tanks are cheaper to buy in the first place.

Condensing tankless water heaters have a condensing unit that captures and reuses the residual exhaust heat before releasing a significantly cooler exhaust via ventilation channels to the outside. This type costs more but has an efficiency rate of around 98 percent.

The first thing to consider is how the water heater is put together. It might be easy or difficult to put together, and you might need more vents and pipes for it to work in your apartment. In your apartment, if it is big or small, this will affect the water heater installation.

Usually, most brands offer a lifetime warranty. This is because it is the best way to be safe. If someone installs your water heater, they will know where it should be placed. You can have peace of mind that your electrical circuits are not damaged or anything else in the apartment.

You can install it yourself if you know how to work on the plumbing or do other handyman jobs. But make sure that you look at YouTube videos and documentation and the manual for instructions to make sure that you are doing things right.

Best Gas Tankless Water Heater 2022:

Rinnai RU160eN

The Rinnai RU150eN has many good features for those who need hot water. It can make 9 gallons per minute and it is enough for many houses. The BTU max is high, too. This is a natural gas system. It is very efficient. It has a condenser that removes as much heat from the exhaust as possible before releasing through ventilation.

This is a good buy. The heater works quietly and effectively. However, it does require some attention. Although this heater requires some installation work, it is not for the faint of heart. If you are not comfortable with pro-level building abilities, please have a professional install this equipment for you.

Depending on the region, there may be some minor modifications required to the plumbing. If you want to know everything there is to know about this product and how it works, go watch Mr. Rinnai Mike on YouTube right now – he does a fantastic job of describing the product line and what needs to be done for installation.


  • High flow rate
  • Great for average households
  • Heats up quickly


  • Pricey



Rinnai RUC98iN (The Best Gas Tankless Water Heater Overall)

This gas tankless water heater is a good choice if your family uses a lot of water. It is more efficient than an electric one because it has natural gas.

The RUC98iN water heater is advanced. It heats the water fast and can distribute it in the entire house really fast. You might not want to buy it because it is expensive and you might have a small household.

It can output 9.8 gallons of water per minute, which means it can be used for taking baths and showers simultaneously. It also has water that you can use to wash your clothes before they get cold.

This heater can heat up really fast. It can be between 98 degrees F and 140 degrees F. And it is small so that it will take less space than other heaters.

Despite the Energy Star certification, which helps with your bills. It is also worth noting that it is hard to install by yourself since it costs $3000-$4000. Depending on where you live, it might come with different PVC or concentric vents, which can be expensive if you need OEM parts.

This product is excellent for both residential and commercial use. But the warranty for residential service is 12 years and the warranty for commercial service is 5 years.


  • Energy-efficient, relatively compact, ultra-fast, extensive temperature range.


  • Extremely expensive, may require additional OEM parts.



Rheem 240V Tankless Water Heater

This little water heater is electric. It is very efficient with a 99% rating. This might not be a good choice for a house with multiple people using the hot water simultaneously, but it would work well for a home with one or two people.

In a 3 Season cottage in the upper midwest, it was installed last month. There is only one shower, one toilet, and one bathroom sink, as well as a single kitchen sink. Ground water enters the house from a private well at temperatures between 45 and 55 degrees Fahrenheit. The flow rate of the Moen Shower Faucet 1.5 gpm I bought is enough for you to shower for ever with no temperature change.

I did observe, however, that when the bath sink is turned on and all hot, our temperature fluctuates a bit, and reducing the water volume on the faucet eliminates this. NO issues with mixing hot and cold typical hand washing temperatures since they are constant, even, and pleasant.

I installed the unit with two separate shut-offs on both sides, and I haven’t yet experimented with the output valve on the heater to restrict the flow out to fix the ALL HOT sink problem, but I believe that restricting that end will remedy the problem.


  • Compact unit
  • Highly efficient
  • Ideal for up to 2 people


  • Does not handle multiple fixtures simultaneously



Stiebel Eltron Tankless Heater – Tempra 36 Plus

The Stiebel Eltron tankless water heater is an efficient, quiet water heater that can heat a lot of water. It also shows how much money you have saved.

I phoned Stiebel Eltron to find out what unit I should buy based on the number of fixtures and flow rate of each fixture in my home (1 shower head, 1.9 GPM; 3 sink faucets, 1.2 to 1.5 GPM). I also mentioned that a master bedroom/bathroom may be added in the future, and that I wanted the water heater to be able to handle it as well.

The Tempra/Plus Sizing Guide, which displays my usual tap water temperature (52* F) and states that the Tempra 29 Plus can handle up to 3.7 GPM maximum flow rate, was mentioned by the customer care representative. “You will be able to operate two showers and a sink faucet at the same time without affecting the temperature or flow rate.” This is ideal for me since it meets my needs. So I bought it.


  • Quiet operation
  • Cost savings displayed on the screen
  • Easy to operate


  • Professional installation required



Hike Crew Portable Propane Water Heater:

For Hike Crew’s portable water heater, you need to put it into a water source and attach a propane tank. You can then use the pump to get ongoing hot water for your camp needs.

This Hike Crew portable is powered by AC/DC electricity. It has some safety features too. For example, when the water runs out or gets up to 125 degrees Fahrenheit, the unit powers off the burner automatically. The Hike Crew can produce 1 gallon per minute (GPM) with 42,000 BTUs. It is not great for all applications, but it is perfect for mobile units.

This was used at our off-the-grid cabin. We had to restart it a few times during the first usage because E3 errors occurred. Since then, we’ve put it in such a manner that the wind isn’t blowing straight through the vents, and we haven’t had any issues since.

We didn’t have any problems with the water becoming scorching hot or dialing in a perfect 105-degree shower. This will be added to our long-term plan as a permanent outdoor shower enclosure. The pump provides enough pressure to remove all of the shampoo from my lengthy hair, which is fantastic! We run the pump off of a Jackery 240Wh and a 5-gallon shower uses approximately 1% of the battery.


  • Ideal for camping
  • Showerhead included
  • It comes with a carry case
  • Lightweight


  • Low output



ECOTOUCH Tankless Water Heater

This small but mighty ECOTOUCH is great for showers or kitchen faucets as a point-of-use unit. It is perfect because it has a high flow rate and BTUs.

This water heater has a 99% efficiency rating. This means almost no heat is lost when the water travels from the water heater to your shower, faucet, or other fixture. All this time, its self-modulation control is monitoring the temperature so that you don’t get too hot or too cold when using one of these fixtures. It can be used in certain rooms like your bathroom or kitchen only if not every room in your house needs it.

This is a huge point-of-use, tankless, on-demand water heater that I had installed under my kitchen sink. Because the hot water pipe from the main water heater passed beneath the slab and needed 3 quarts of chilly water to be lost before any hot water emerged, it was required. Now I have instant hot water. Yay!

This installation required an electrician to install an 8 gauge, 40-amp, 240 volt service to the unit as well as a plumber to connect the unit to the pipe with the dishwasher and faucet. As a result, purchasing the heater unit was only a minor aspect of the overall expenditure. The heater unit is tiny and effortlessly attaches to the side of the cabinet, away from the ground, out of sight, and inconspicuous.

I appreciate the fact that I have no mechanical switch or knob, and the temperature of the water may be adjusted simply by touching the front of the device. There are no moving parts to it. Set it at 120 degrees since 120 appeared to be a little high for me.

The plumber informed me that there is a screen in the intake to catch debris. He recommended turning off the water to the unit (he installed a quarter-turn ball valve) and rinsing out the filter screen if the flow decreased.


  • Affordable
  • Almost no heat loss
  • Great supplemental unit for a bathroom or kitchen


  • Not suitable for an entire home



How We Chose the Best Tankless Water Heaters

The best tankless water heaters are energy efficient and work well. They can pump out hot water for an entire household. Our list of recommendations gathers the best products that stand out from their competitors regarding reliability, energy-saving features, and flow rate. We offer the most reliable units in the market with reasonable flow rates and low energy consumption. You can choose between gas or electric units.

Our top picks also include some technology for when you are saving money. They can help you save money for hot water and electricity bills. We looked at different venting options to provide recommendations that would work for people in different sizes of homes.

We wanted to help you have a good time outside, even cold. So we took a shower so you can take one there.

Q: How does a tankless water heater work?

A tankless water heater is a machine that turns hot water into the cold. The heat exchanger heats the cold water that enters it. When someone turns on the faucet, the flow-activated switch turns on the heating element so that there is hot water for them to use. That way, they don’t have to wait for it to make more hot water. The water then goes through a series of loops within the unit, gaining enough time to reach its target temperature before exiting at a fixture in your home.

Q: What size tankless water heater do I need?

The size of the tankless water heater you need depends on how many people live in your house, what they use it for, and the local temperature.

If you live in a home with one to three people, you should get a water heater that puts out 3-5 gallons of water per minute. If four or more people live in your home, you should get a water heater that puts out up to 8 or 9 gallons of water per minute.

Q: How do you flush a tankless water heater?

To shut off the water, you need to turn off the electricity and gas (a gas water heater). Next, connect hoses to the cold and hot water isolation valves. The hose connected to the hot water should not be attached anywhere else. The hose connected to cold water needs to be attached to a pump.

Fill a bucket with about 4 gallons of white vinegar. Put the pump in the bucket and fill it up with water. Then turn on the pump to let the vinegar clean your tankless water heater for 45 minutes or an hour. Turn off your pump and empty out all of the vinegar before you leave.

Next, turn the cold water on for five minutes to allow it to flow through and remove the vinegar.

Once you finish, turn off the water, disconnect the hose, and put back on your tankless water heater.

Test your water heater to see if it is working. If not, find out why. You will need to do this with power and fuel sources. If there is a problem, you might want to call a plumber for help.


This is the end of our list with the best gas tankless water heaters. If you want to use something other than natural gas, see this list with the best power-efficient electrical tankless water heaters. We tried to make it easier for you by breaking down difficult information into easy points that can be understood.

Hopefully, this list will help you find a water heater for your home based on the size of your house. If you have bedrooms that are small with less than two bathrooms, then look into smaller water heaters. Also, if you need to run more appliances that require hot water at the same time, then check out some higher-end models from our list like Rinnai’s.

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