Tankless water heaters reviews

3 Best Tankless Gas Water Heater: Review of Propane, Natural Gas Hot Water Heaters [2021]

(Last Updated On: December 1, 2020)

Tankless gas water heaters last longer than tanked heaters, provide on demand hot water whenever you want it, for as long as you want it, and will save you a nice chunk of change every month. Most reviewers report 30-40% reductions in their energy bills! These devices are a worthwhile investment based on their convenience alone. Their financial savings, environmental friendliness and energy efficiency only sweeten the bargain!

Compared to electric models, gas tankless water heaters have better cold-weather performance and average lower fuel costs over time. They’re also more reliable over the long term.

To get the full range of benefits, it’s super important to select the right water heater for your household’s specific needs. The range of options on the market is vast and it’s all too easy to get an inadequate unit for your needs, or to overpay for one you won’t fully make use of. This equipment can be costly, especially because gas units require you to install proper ventilation ports and fuel hookups. This guide will help you get it right the first time.

We’ve got the know-how, and have come up with a list of high-quality options available today. We’ve sorted them into easy categories: top sellers, highest overall quality, and the best value buys.

ModelProduct ImagePrizeRatingPriceMax. FlowrateSuitable House Size?Suitable Climate?
EZ Ultra HE Natural Gas Condensing Tankless Water HeaterBest Value4.2$$Variable (2-3 fixtures)Small-MediumCold
Rinnai V75iN Tankless Gas Water HeaterBest Medium-Demand Heater4.5$$$7.5 GPMMediumCold
Rheem RTGH-95DVLN Tankless Gas Water Heaterlow NOx water heaterBest High-Demand Heater4.4$$$9.5 GPMLarge Anywhere

Best Gas Tankless Water Heater Reviews

1. Rinnai V75iN Natural Gas Indoor Tankless Water Heater (7.5 GPM)

“a good choice for the average household.”

Rinnai’s V75-IN is our top lower price recommendation for a gas tankless water heater. It’s rated at up to 7.5 GPM, and we think it’s a good choice for the average household.

You can easily run two or three things at once on this (provided you’re using low-flow plumbing fixtures and efficient appliances), depending on where you are. It’s part of Rinnai’s High Efficiency series, and has a superb .82 energy factor.


With an output of up to 7.5 GPM, the Rinnai is ideal for the average household, in any climate. You can easily have two showers running at once on this one, and still have some spare hot water for a sink. Or, you could run a load of laundry, take a shower, and have someone else do dishes at the same time.

“ideal for the average household, in any climate.”

Your actual results will depend on the efficiency of your fixtures and appliances, as well as your inlet temperature. Still, this is a good choice for the average small to medium-sized household where several things are often running at once.

It’s very efficient, as we’ve already mentioned, and it has low emissions ratings to boot. The Rinnai is SCAQMD-approved. This is a lot more environmentally-friendly and energy efficient than other gas units under $1,000.

It’s certified for mobile and prefab homes, too! A lot of tankless models aren’t, which is a shame because they’re ideal for tighter living spaces.

“You wouldn’t feel bad leaving this exposed”

Like the best tankless water heaters, the Rinnai is neat and compact: 14” x 9” x 23”. We think it looks good, too. You wouldn’t feel bad leaving this exposed, especially if you can install it next to another white appliance (such as a washing machine).

We think the controls are just right on this one. Some models these days are annoyingly “tech-y” and draw more attention than you want to a water heater. The Rinnai has an unobtrusive display, but still gives you easy access to everything you need.

You can choose settings between 98-140 degrees. There’s a temperature lock to prevent any accidental changes to the water temperature settings and limit.

Rinnai units have a great track record for long-term performance. This tankless heater has as solid a reputation as you’d expect from the brands. We haven’t discovered any long-term issues or design flaws.

You’re covered by warranty for 10 years on the heat exchanger, 1 year on labor, and 5 years on parts. Follow the links in this review to purchase one with extended warranty coverage, if you like to add that.

One reason we prefer this to other gas units is the smart safety system built in. It’s a well-designed way to keep things sound for years. Scale detection prevents any damage to the unit and automatically shuts things off if you haven’t followed the cleaning schedule, or if your water composition needs more frequent descaling.

There’s also built-in leak detection, which is a fantastic feature we wish more companies would roll out. If one of these should somehow spring a leak, it’ll sense it and shut itself off to prevent water damage. That’s the worst case scenario when water heaters go south, so we’re big fans of this feature!


Like any lower priced tankless model, it’s a bit slower to respond. It’s still only about a 30-second wait for most people.  Some other models may get you hot water slightly faster, but the Rinnai has a higher capacity once it’s up and running.

You’ll need to get a direct-venting kit. This doesn’t come with anything but the heater unit.

This is our recommendation to the average home. That’s a pretty vague term, so you should get some hard numbers to use as a benchmark for your water requirement. In general, this ought to be suitable for the typical family in a small to medium-sized home. Medium and large homes with heavy usage requirements, or medium size homes in particularly cold areas would be better off with the Rheem below.

2. Rheem RTGH-95DVLN 9.5 GPM Indoor Direct Vent Tankless Natural Gas Water Heater

low NOx water heater

“one beast of a tankless water heater!”

This is one beast of a tankless water heater! Someone could take two showers, run the dishwasher, hand wash a pan, and do a load of laundry––all at the same time! Not only does it have a massive output capacity, but it uses energy very sparingly. It’s a condensing unit, which is the most energy efficient gas option on the market.

All that power and efficiency comes at a cost that will make it prohibitive for a some folks, but if you have a large demand for instant hot water, this is a great investment. It’s easy to install, works quickly and quietly, and can compete with any tank model in the flow department. And of course, you’ll never run out of supply!

This is a great natural gas tankless water heater for big households or small/medium households with high demand. The Rheem is not intimidated by even the coldest of climates. It’s also the ideal tankless model for folks who never want to have to think about managing their supply of hot water. If price is no object, this is the unit you want, without question!


With a very high flow rate of 9.5 gallons per minute (GPM), this Rheem could heat three full-flow showers at once. You truly will never run out of hot water with this one, even at times of peak usage. It’s ideal for larger households, even 4-bedroom and larger.

“It’s ideal for larger households”

With this Rheem, the coldest climates will never cause a drop in pressure or temperature and you do not have to compromise on functionality, ever. We’ve heard from buyers in the coldest parts of the country who have all attested to the fact that it cranks at full-bore no matter the weather.

Also, as a condensing unit, this Rheem extracts heat from exhaust gasses, which makes it more energy-efficient and thus cheaper long-term than non-condensing models. Efficiency is third-party certified to 94%; non-condensing heaters max out around 82% efficient, even in ideal conditions.

And because the exhaust gasses aren’t as hot upon their exit, you can use cheaper venting options in the installation phase! There’s a built-in electric blower to help out with venting, too. That’s something a lot of other large models neglect to include.

As with the Rinnai, it’s a low-NOx model. Between the low emissions and the ultra-efficient design, it’s comparable to many electric models in the eco-friendly department.

“it’s comparable to many electric models in the eco-friendly department.”

It includes a remote control in the box, so you don’t need to buy anything separately.

Many other large-capacity tankless models are fairly industrial, but this Rheem balances brute force with brains. It has lots of smart features, like the Rinnai. There are self-diagnostic controls, and maintenance codes are displayed on the panel, as well as temperature settings. You can quickly pair these units up, and they’ll work together seamlessly to heat the largest demands.

“They don’t come hardier than this!”

It’s still industrial-quality, though. The Rheem works up to 9840 feet above sea level and packs freeze protection to -30F. They don’t come hardier than this! If you’re in an extremely cold spot and need to compensate, this should be right up your alley.

As with our other recommendations, the Rheem is extremely reliable. It has a 10-year warranty on the heat exchanger, and 1 year of coverage on the parts.


The big drawback to this unit is the price tag. It’s the most expensive gas model we recommend. Be prepared to spend $1,200 or more for the heater, not including fittings or installation costs.

This is overkill for a lot of people. Smaller households (1-4 people) do not need something this powerful, and can very easily do with one of our less expensive options. Be sure to come up with your own GPM requirements and check your inlet temperature, to make sure you can justify buying this!

3. Rinnai RU199 Sensei SE Tankless Hot Water Heater


If you have a bit more to spend, have a large household, and love innovative technology, you can move up to the Rinnai RU199.  This will likely cost at least $1,500.  At 11 GPM, this will provide far more hot water than the Rinnai V75 (at 7.5 GPM) and 16% more than the Rheem (at 9.5 GPM).

This Rinnai has ThermaCirc360 Technology, which recirculates hot water through your pipes to get you hot water ultra fast.  To understand why this is great, let’s compare it to your old tank water heater.  While you wait would normally wait for your hot water to travel from your old tank to your shower, you could waste the equivalent of 24 16 oz bottles of water each time, or 8.700 bottles of water per person per year!

This model even has WiFi monitoring so that your Rinnai service provider can monitor the efficiency of your water heater and address issues remotely and before you ever experience a break in service.


With the highest flow rate of the water heaters reviewed, this would be your best best for large households.  If your family members are all on the same schedule and you have multiple bathrooms, you could feel comfortable that everyone can get ready for work and school and once with no one being left out in the cold.

“We are a family of 5 and use LOTS of hot water…The benefits are being noticed…I won’t be going back to a tank.”

“The unit can handle both showers running at full blast and I’ve also ran the 3 third floor faucets, shower, and tub with hot water still coming out of all of them.”

Not only is there endless hot water with this model, but it is very efficient with multiple reviewers stating immediate cost savings on their energy bills.

“I replaced 2 40-gallon electric water heaters with this tankless gas unit. My electric bill has been $150 less a month, and my gas bill has only gone up $8.”

Although most of you would probably prefer to pay a professional, many reviewers raved about how easy this was to install on their own and saving a couple thousand dollars of labor costs.

“In about one day I was able to single-handedly remove the original tankless water heater and install the Rinnai without blowing up or flooding my home.”

“Clear and precise instructions. Only took about an hour to install.”

In general, most people have nothing but good things to say about this water heater, but as with anything in life, there are a few drawbacks.


The water take a bit of time to reach the furthest faucets, with some people claiming it can take up to 30 seconds to a minute to arrive. Reviewers suggested buying one with the recirculation pump.

“Only downside is it takes a long time for the hot water to reach the faucets if you don’t have a return line installed.”

The only other issue reported by some was that it can be a little loud if it’s installed in closet next to where you sleep.  Most people install water heaters in a garage, storage room, or closet away from bedrooms, so in general, this wouldn’t be an issue.

“It’s not that bad but I wouldn’t mount it in a closet close to where you’ll be sleeping…It produces around 45db, but when it’s mounted to an interior wall, the sound resonates a bit more.”

Overall, if you’re willing to shell out some money, this unit gets a glowing endorsement for larger households.

Buying Guide

The promise of tankless gas water heaters (unlimited hot water on demand, and substantial long-term energy savings)! will only ring true for you if you buy a unit that’s appropriate for your needs. With so many options to choose from, it’s a tricky thing to find your ideal balance between price and functionality.

A hugely important factor to consider is household size.

Generally speaking, an apartment shouldn’t need the same gallons per minute (GPM) output from its water heater as a five-bedroom house. If you’re only running one shower or hot water-driven appliance at one time, there’s no reason to spend lots more money for something that’s designed to run several.

That brings us back to price. A smaller household or apartment can get its needs met with a much cheaper unit. Likewise, people who own larger homes with multiple bathrooms should plan on spending substantially more at the checkout. The bottom line is tankless water heater prices will vary greatly dependent on size and features.

To figure out how much you need to spend, you need to figure out how much hot water you need at any one time. This is a matter of finding your GPM (gallons per minute) usage. Look at the GPM rating on your shower head to find out how much water it uses.

The shower is by far the appliance with the largest hot water demand. The standard shower ranges from 2.5-3 GPM, while low-flow showerheads typically output 1.5 GPM. Now check your sinks. It’s also a good idea to check your appliances like a dishwasher or a washing machine to see how much they use.

Then, think about how many of those feeds you use at once, and how much that total GPM would be. For instance, if you live alone but like to run a load of laundry while you shower, you will want to add the washing machine to the shower head to get your total. If you live alone, and don’t run any other appliances while you’re in the shower, your total will simply be the flow rate on your shower head.

We always recommend rounding up by about 50% of your total requirements, in order to give yourself an appropriate margin of error.

In colder climates where your unit will have to work harder to heat your water, you should round up by as much as 75-100%. That’s because most models are tested at average input temperatures, which don’t apply in some far northern or high altitude regions.

Climate determines the temperature of incoming cold water, which in turn determines the effectiveness of your hot water heater. The GPM output that companies list is the maximum possible output of water that unit can heat. You do not want to underestimate demand, especially in colder climates. Tropical climates like Florida can get away with much less powerful units, even in large households, because the heaters themselves have to do so much less work. Conversely, an apartment in Chicago should probably invest in a more powerful unit.

The final thing to consider is installation cost: specifically, the amount you’ll have to pay for venting construction and retrofitting your gas line. Tankless gas water heaters have a higher upfront cost than their electric counterparts. That’s because indoor units must be vented, and outdoor units cost even more to be weatherproofed.

Even if you’ve already got a gas line going into your house, you’ll probably need to make some slight modifications. Most water heaters with tanks use a ½” gas line, but most tankless heaters require a larger gas input, ¾” at least.

In short, installation isn’t usually as simple as just plugging and playing. It’s always worth consulting a qualified plumber to determine the full cost of retrofitting your house for a tankless gas heater before you buy.

All that said, though, natural gas is significantly cheaper than electricity, and if you pick the right unit that lasts, you will save money every month until it pays for itself. Most buyers say that their machines paid for themselves within the first 1.5-2 years!


All of our recommendations are reliable, efficient and rugged. They’ll all last for years of service, and they should all more than pay for themselves over time. Still, the best one for you depends on your specific needs.

The Rinnai V75IN is the best choice for the “average” person, who wants to comfortably be able to run 2-3 things at a time, in any climate. It give you enough extra power to avoid budgeting your hot water usage so much. It’s not what we would consider inexpensive, but gas tankless water heaters tend to be more expensive, and we found this one to have the biggest bang for the buck.

The Rheem is the best way to go if you don’t want to worry about capacity in a larger household, trust that the unit will be reliable, and still be a bit cost conscious.  However, at around $1,200, this unit is fairly expensive. Even if you have three bathrooms, you can shower in each of them at the same time. It’s ideal for larger households, spacious homes, and folks who simply don’t like to have to budget their hot water use. Just know that it’s quite expensive, and that many people don’t actually need something this powerful.

The Rinnai RU199  is the most expensive unit reviewed, but this unit would be perfect for large households in any climate if you have the extra money to spend.  At an 11 GPM flow rate, you never have to worry about running out of hot water and the energy savings will certainly help you feel better about the initial investment.

What’s Next?

Electricity might be more expensive than natural gas in the long run, but many people prefer electric heaters because the upfront cost tends to be lower, both in the cost of the unit and in the installation. See our overall picks, read our Best Tankless Water Heater Reviews !

Tankless Reviews was created with the goal of helping people to understand the benefits and practical knowledge related to tankless water heaters. After purchasing my very first tankless heater years back, I realised that other people needed to hear about the incredible money-saving ability of this household item, and wanted to share my lessons with you!