Best Propane and Natural Gas Tankless Water Heaters

Are They Worth It?

Propane and natural gas tankless water heaters are by far the most common kind. I have the opposite problem choosing a gas tankless heater than I do an electric one.

With electric ones, the vast majority are simply BAD, with a number of shining gems that stand out like diamonds in the rough. Gas ones on the other hand?

There’s an enormous number and variety to choose from, most of which are pretty good. But pretty good wasn’t really enough for this list. I needed the best of the best, which is hard to suss out even when you know what you’re looking for, much less if you haven’t spent as much time poring over these units as I have.

Hopefully this list (and my others) help severely narrow down the range of what you’re looking for, particularly with the more common brands (most of whom have several nearly identical models in the same price range that are only differentiated by special features).

Are you in a Rush?


Noritz 11.1 GPM Built-In Recirc. Pump

Top Gas & Propane Tankless Water Heaters

Noritz 11.1 GPM

Built-In Recirc. Pump

Noritz EZ Series

11.1 GPM Gas Tankless Water Heater

Rinnai RUR98iN

Condensing Indoor Natural Gas Tankless Water Heater

Takagi T-H3J-DV-N

Condensing High Efficiency Natural Gas Indoor Tankless Water Heater

Rinnai C199EN

Commercial Condensing Tankless Water Heater


Indoor Direct Vent Tankless Natural Gas Water Heater

Rheem RTG-84XLN

Low NOx Outdoor Tankless Natural Gas Water Heater

Takagi T-H3-DV-P

Condensing High-Efficiency Propane Indoor Tankless Water Heater

How to Choose the RIGHT One?

First and foremost, you should only consider units made by reputable and dependable brands. After all, it’s a product you will use every day for the next 30 years. There are many other factors you should take into account before you buy. The most important must-know modifications are outlined below. Click on the items to see more.

Water Flow Rate

Measured in units of GPM (gallons per minute), the flow rate determines how much hot water can run at the same time. The average shower has a flow rate of 1.5 GPM, while the average kitchen sink uses 1 GPM.

For example, if your home has two showers, you need a heater with a maximum capacity of 4 GPM or greater. Otherwise, two people won’t be able to shower at the same time while someone is washing the dishes or vise versa.

Your Household

The ambient temperature of H2O from the grid is stable all year long with the exception of below-freezing weather. For obvious reasons, if you live in a colder climate, you will need a more powerful heater. Ideally, it should be able to heat to 150° F at your maximum flow rate on the coldest winter day.

If you’re worried about the efficiency – don’t be. Most tankless units are compatible with electronic controllers that let you dial down the burner.

Gas Supply

Not all are compatible with low-capacity of supply lines. So make sure to check whether your existing line would support a heating machine. If it isn’t sufficient, you will need to get it replaced with an upgraded version.


Every gas-powered units has a certain ventilation rate requirement. They only run on clean-burning natural gas but the fumes still require an exhaust. As such, you’ll need to install an adequate venting system.

Top Rated Models On The Market Today

Noritz 11.1 GPM Built-In Recirc. Pump

Is, bar none, the most powerful tankless water heater I can find.

It has almost everything I would conceivably look for. A massive 11.1 GPM starts us off, with a 199k maximum BTUh condensing heater (94% efficient). This bad boy performs well in the cold too, still retaining a more than respectable 8 GPM in places with colder groundwater.

These raw stats alone would be enough to catapult it up near the top of any list I decided to feature it on, but its host of special features are what really sells it as a true winner.

Starting with the simple, it has ultra low NOx emissions (something I always try to look for in a tankless water heater, and which has become relatively standard among the mid to top range models) and remote control capability (ditto).

What really cements its spot though? It has a built in recirculation pump. I cannot overstate how much better a tankless water heater with a recirculation system is compared to one that lacks it. It’s such a huge boost to efficiency that the raw stats above somewhat belie its real capabilities.

I’ve explained how this works elsewhere, but a quick review here: recirculation systems (not standard in most homes, but a conversion kit can be fairly easily found to convert your cold water line into one on demand) cycle water that goes down the drain back into circulation, passing it through the heater again and back out of the faucet or showerhead.

In essence, instead of a lot of the hot water being wasted after it bounces off your skin a fraction of a second after coming out of the shower, it’s recycled and reused so the water stays hot longer and with less strain on the heater.

Both of the tankless water heaters I considered for the top spot have this feature; all others were automatically knocked down a notch. The only real downsides to this tankless water heater are the price (a little under $1500, a fair price but really hammers home that this unit shouldn’t be gotten if it’s overkill for your home) and its lack of commercial application for anything beyond light commercial use. It lacks the main feature that one of our runners-up actually has, the ability to connect multiple units together to form a more powerful tankless water heater.

Noritz 11.1 GPM EZ Series

Close, but no cigar.

This unit is very close to our winner, but ends up a few spots down for an important reason: it lacks the recirculation system.

Almost everything else is the same: it has the 11.1 GPM (7 or 8 GPM in the cold, and 6 GPM when the groundwater is near freezing temperatures), the 199k BTUh maximum (and 18k BTUh minimum), the ultra low NOx emissions, and the remote control capability.

It also has something our winner was not graced with, namely easy installation features. On this one the vents are located in such a way that they’re designed to be easily plugged in where a tank water heater would be, replacing it outright with the tankless equivalent in the same spot (this one is meant to replace a roughly 70 gallon tank, for reference).

While that feature is nice, and great for somebody upgrading from a tank water heater to a tankless once rather than building a new place that goes tankless from the start, the lack of the recirculation pump built-in really hurts it in the raw efficiency aspect.

Given it’s only about $20 cheaper than our winner I couldn’t give it the top slot. It’s good, even great, but not THE BEST.

Rinnai RUR98iN

Rinnai’s best is also one of our close contenders for the top.

This sucker hits 9.8 GPM at max (7.7 GPM where the groundwater is around 60 degrees, and a still solid 5.5 GPM in near freezing temperatures), with a 199k maximum BTUh coming from a condensing heater, making it one of the most powerful out there.

It also has high altitude capability, working perfectly up to 10, 200 feet above sea level. Not bad.

In addition to those impressive raw stats, it has a number of quality of life features and extras, including wifi control (largely pointless in a residential setting, but great for small to medium-sized businesses) and of course, a recirculation kit. Similar to the Rheem model above, this one gives you the tools needed to convert your cold water line into a makeshift recirculation line.

This one would be the absolute top dog if it weren’t for the massive price difference between this one and the Noritz that took the top spot: this Rinnai will run you over $2000, a tidy sum.


Rinnai’s best is also one of our close contenders for the top.

While it takes a solid hit in the raw output department compared to the monstrous power of the Noritz models above it on this list, it has a few advantages over them.

In terms of basic stats it boasts a solid 9.5 GPM, 199k maximum BTUh (11k BTUh minimum), and is a 93% efficient condensing model (lower by a percent than out winner and by a few percent than most other units on this list).

Where it really shines though is luxury features. It has the mostly standard features of remote control (or app control, so you can control it by phone) use and ultra low NOx emissions, as well as freeze protection up to -30 degrees (a godsend in these cold climates).

Additionally, it has our old favorite the recirculation kit (in this case, it not only has the pump but comes INCLUDED with the kit needed to retrofit your cold water line as a recirculation line when needed), and “hot start programming” that lets you tweak how the heater works to make it more convenient.

A primary feature is making the heater run a minute or two after you turn a faucet off, making it possible to shut the faucet on and off in relatively rapid succession and still ensure hot water comes out instantly.

It sounds simple, but is insanely useful, at least to me. When I wash dishes I don’t like to leave the water running the whole time, I turn the faucet on and off for a combination of conserving water and making it easier to hear the TV, whatever podcast I have running at the time, or whoever I’m talking to better.

With most tankless water heaters, turning off the faucet for more than a few seconds means the whole heater shuts off and you’re left with waiting for the hot water to build back up again, wasting a bit of time each time you turn it off. So to me, this is an insanely good feature.

Of course, all of this comes at a price: nearly $1700, which is why this one ends up a strong contender for second or third place…but doesn’t quite hit the top, where our winner has both far more power and is about $200 cheaper.

Still, the luxury features on this bad boy should not be ignored, and $200 might pay for itself over the course of a few years anyway.

Rinnai C199EN

The only model primarily made for commercial use on this list.

This is identical to the Rinnai RUR98 (above) in many ways, including most of its basic stats. 9.8 max GPM (7.7 in the cod, 5.5 when it’s VERY cold), 199k BTUh, a 96% efficient condensing heater, the whole nine yards.

This one’s main claim to fame is its commercial applications. Up to 25 of these bad boys can be linked together to form one super tankless water heater: a Megaheater, if you will.

As far as I know the Megaheater doesn’t perform perfectly linearly (i.e. 25 C199’s are not just 25 times as strong), but it’s still quite a good investment for very large businesses.

Emphasis on “very large” though. Funding a boiler room full of these things is likely to break the bank for most businesses: each one of these will cost you nearly $2000, a hefty investment for a small to medium sized business that could potentially make do with a few Point of Use models scattered around.

This one is nowhere near the top of my list for that relatively niche application (there are other, better, cheaper models for residential use) but it’s good enough I felt it deserved a mention.

Rheem RTG-84XLN

An excellent Rheem, but not excellent enough.

My main issue with this one is it’s non-condensing, leaving its efficiency (and therefore its cold weather effectiveness; the two go hand in hand) at an abysmal 81%.

Besides that, most of its other features are very good, being an 8.4 GPM unit (though that drops to a less impressive ~5 GPM in the cold), with a 180k maximum BTUh.

One thing that pumps it up a notch in my estimation is that it does come with the same recirculation kit as another Rheem we’ll cover below in more detail (which is much better in most regards), raising its practical efficiency by quite a lot.

Is this a massive powerhouse like our winner or most others on our list? Not by a long shot.

But in many cases…you don’t need that. If you only use 5 GPM at a time on average, you don’t need an 11.1 GPM unit by any means. Factor in that this unit is also significantly cheaper (under $900) and has a light commercial application (they’re designed to be linked together with others for more power) and you have yourself a good option for many homes.

It’s good enough to earn a spot on the list, anyway. Even if it is near the bottom.

Takagi T-H3-DV-P

Takagi’s best, but lacks the “wow power” to be close to the top.

Much like the T-H3J below, this one sits on the cheaper end of the spectrum (a bit over $1100) of our units today. That’s not a bad thing, necessarily, since it has quite a lot of raw power under the hood, even if it ones lack the special features required to take a higher spot.

This outputs the full 199k BTUh in its 93% efficient condensing heater, and can hit up to 10 GPM (with the usual drops you’d expect for colder climates).

Much like its little brother, it has a wide array of protection features, being protected against freezing, overheating, and surges or lighting strikes along with the same 15 years on heat exchanger and 5 years on parts limited warranty.

Its only downfall is its lack of special features. Particularly it lacks the recirculation pump the cheaper (though less powerful) Rheem RTGH-95 (below) and our other runners-up possess, making it inherently less efficient no matter what the extra .5 GPM at the baseline implies.

The final nail in the coffin is the price…the aforementioned Rheem is about $200 cheaper, has close to the same base stats, and comes with a very important feature this Takagi can’t hope to match.

I should reiterate: this unit is NOT BAD, it’s actually very good. It’s just…simple. And while simple can sometimes be great, in this case it’s a big hit to its comparative quality.

Takagi T-H3J-DV-N

Don’t feel bad for this Takagi just because it’s at the bottom.

Something always has to bring up the rear even on a best list, but that doesn’t mean it’s a bad product. On the contrary, the Takagi T-H3J is quite excellent.

It outputs a fairy low but still respectable 160k BTUh from its impressively efficient (95%) condensing heater. That translates into a 6.6 GPM in warm climates, dropping a couple of GPM in the colder areas of the world.

Still, 6.6 GPM (even 5.5 GPM, actually) is enough for a lot of homes. That’s two showers and a dishwasher plus a washing machine, more than enough for any two bathroom home. Most of the others on this list are monster powerhouses largely because they are the best their brand offers in other ways, but I figured I’d take a moment to acknowledge that smaller units can be really good too.

The main thing that puts this so low is the lack of extra features more than its lower power. It doesn’t have much worth talking about except an excellent
warranty (15 years on the heat exchanger, 5 years on the other parts) and its wide range of protective features. It has freeze protection, overheat protection, and surge (or lightning strike) protection, making it one of the more durable tankless water heaters out there.

Not bad for the ballpark of $900.


Noritz 11.1 GPM Built-In Recirc. Pump

Rinnai has been the leading gas heater manufacturer for over two decades now. And their Ultra Series is the most efficient burner ever made.

The Energy Star Qualified model uses condensing technology for 96% thermal efficiency, which is 15% above standard tankless models units.

At 199,000 BTU, the RUC98iN is the largest Ultra Series model available. It has a heating range of 98° F to 140° F with the capacity to easily handle multiple water sources.

And reliability is backed by a 5-year manufacturer warranty for all parts as well as a 12-month warranty on labor.

It’s also an RUR model, meaning it features Rinnai’s ThermoCirc360 technology for virtually instant hot water from the second you turn on the shower/faucet.

The system comes complete with a built-in recirculation pump, an internal bypass line, and an optional dedicated return line.

Annual maintenance is simplified thanks to the isolation valves. The Ultra Series is compatible with both Concentric Polypropylene and dual-pipe PVC/CPVC venting system.

However, it must be installed on an exterior wall in order to vent outside.