Rinnai Tankless Water Heater Reviews

Introduction to Rinnai

Every brand in every kind of product has some kind of specialty. Rinnai’s specialty is having the highest overall performance of any brand.

Pound for pound an equivalent model from some other brand will lose to a Rinnai whether it be a high-end Rinna vs a high-end something else, or low end vs low end (or in some case, a middle of the road Rinnai vs a high end some other brand).

So today I’m going to pull out what I feel are the best Rinnai models that price themselves fairly; if another brand does about the same job but cheaper I’m leaving it off, going only for the best of the best here.

Best Rinnai Instant Heaters


Rinnai C199EN

Rinnai RUR98iN 9.8 Max GPM

Ultra Series Condensing Indoor Natural Gas 

Rinnai V65EP

6.6 GPM Outdoor Low NOx Propane

Rinnai RL75iN

Natural Gas, 7.5 Gallons Per Minute

Rinnai RUC98iN Ultra Series

Natural Gas, Concentric/Twin Pipe Installation

Rinnai C199EN

Commercial Condensing 

A Quick Overview Of Terms

I use a few uncommon abbreviations and terms in this article, which I’ll quickly explain here:


British Thermal Unit (per hour), the amount of heat required to heat one pound of water one degree. The higher this number, the hotter your tankless water heater.


Gallons per minute. In this context, how many gallons per minute a tankless water heater can effectively heat without starting to output cold bursts. Bigger is better, once again.


A condensing heater keeps the propane or natural gas more highly compressed, resulting in more efficient heat output that isn’t as affected by the weather. Non-condensing units (the majority) lack this feature and may perform up to 50% less efficiently in cold weather.

Top Rinnai Choices For Your Money

A beast of a machine.

In terms of raw power, they have that in spades, with a 9.8 GPM at a relatively low heat rise, while still maintaining a respectable 5.5 GPM at a 70 degree rise in temperature.

This makes it a perfect all weather tankless water heater, maintaining most of its high (96%) efficiency even with the coldest possible groundwater, putting that 199k BTuH to good use.

It can run on either propane or natural gas depending on what’s available (the EP is propane, the EN is natural gas), and in either case it is an energy efficient condensing heater.

Like almost all Rinnai models it is also Energy Star certified and Wi-Fi capable for remote control via computer or even phone.

This doesn’t make it to the very top of the list because it’s beyond overkill for most people, and others perform as well or better for residential use, but in terms of raw performance this is the best on the market.

Top of the line for large residential or light commercial tankless water heaters.

199k BtUH translates into a maximum of 9.8 GPM at a fairly low rise in temperature (about 30 degrees), making it amazing in warmer climates for huge homes or a medium sized business.

This is hard to beat in any climate, warm or cold as a result, and works for altitudes up to 10, 200 feet above sea level.

The HUGE need here is recirculation.

efficiency in hot water. It gets pumped back into circulation instead of just floating out the drain and all that hot water being lost.

The only real downsides (as with ALL Rinnai tankless water heaters) are bulk and price. It’s the size of a suitcase and weighs roughly 82 lbs, and has a similarly hefty price tag: a bit over $2000.

Still, you can’t say they’re particularly gouging you, that’s simply the fair price for such high performance metrics. It’s a bit overkill for many homes, but when you need that kind of raw power and don’t want to sacrifice comfort and ease of use, Rinnai has you covered.

If you need a cheaper option for more compact homes, this has you covered.

This has a slightly above average 150k BTuH with a decidedly average 6.6 GPM, making it perfect for the average two-bathroom home.

It is an 82% efficient non-condensing propane unit (it also comes in natural gas if necessary), which actually makes it a little bit more efficient than many non-condensing units (by a percent or two).

The primary draw here is that it’s certified for use in manufactured or mobile homes, which is actually a rarity among tankless water heaters. This makes it both a solid option in its own right, and one of the ONLY options for someone in a mobile home to use.

I highly recommend it if you want a good, cheap tankless water heater for your average sized home and don’t need the huge overkill capacity of many of the rest on this list.

RUC98iN Ultra Series

So close to our top model, and yet not quite.

The main thing it lacks is the recirculation system. Now, before I continue, I do want to say that being close to $500 cheaper than our winner, this is a much better option for anyone that doesn’t need the recirculation system, hands down.

Lacking that inherently makes it a much less efficient system. But it IS overkill in a lot of cases, so this takes rather than second place, more first place with a caveat: it’s only better if you don’t need that extra bit of heat efficiency.


Rinnai C199EN

Every tankless water heater on here is the best for somebody in some situation, with the possible exception of the RL75. Of particular note is the RUC98iN Ultra which lacks only one feature (albeit an important one) over the RUR98 and comes in significantly less expensive.