Outdoor Tankless Water Heaters

Are you looking to save space by purchasing an outdoor tankless water heater? We’ve reviewed the best outdoor tankless water heaters on the web and narrowed it down to our top 5 choices. Picking the right water heater for your home is an important task that will last you for decades, so we’ve done our best to make that choice as easy as possible for you.

Please be sure to read each of our outdoor water heater reviews to ensure you get the right unit for your household.

Outdoor Tankless Water Heaters

Name/Image Learn MoreBrandRatingPower SourceUse TypeCapacityType
Rinnai RU90eN Ultra Series Outdoor Water Heater Review

Rinnai RU90eN Ultra Series Outdoor Water Heater Review

view pricefull review Rinnai5 Star Average Rating Natural GasOurdoor9.0 GPMTankless
Takagi T-D2-OS-NG Outdoor Tankless Water Heater Review

Takagi T-D2-OS-NG Outdoor Tankless Water Heater Review

view pricefull review Takagi4 Star Average Rating Natural GasOurdoor10 GPMTankless
Rheem RTGH-95XLN Prestige Tankless Water Heater Review

Rheem RTGH-95XLN Prestige Tankless Water Heater Review

view pricefull review Rheem4 Star Average Rating Natural GasOutdoor9.5 GPMTankless
Rinnai RL94eN Outdoor Tankless Water Heater Review

Rinnai RL94eN Outdoor Tankless Water Heater Review

view pricefull review Rinnai4.5 Star Average Rating Natural GasOutdoor9.4 GPMTankless
Rheem RTG-84XLN Outdoor Tankless Water Heater Review

Rheem RTG-84XLN Outdoor Tankless Water Heater Review

view pricefull review Rheem4 Star Average Rating Natural GasOutdoor8.4 GPMTankless

Rinnai RU90eN Ultra Series Outdoor Natural Gas Tankless Water Heater

Rinnai RU90eN Ultra Series 9 gpm Outdoor Natural Gas Tankless Water Heater

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If it’s energy efficiency you’re after, then the Rinnai RU90eN Outdoor Water Heater is right for you. With the absolute leading energy efficiency of 96% on an outdoor tankless water heater, this unit will line your pocket with up to 6% in energy savings every time you use it. While more expensive than some of the other leading outdoor units, and without the raw power, the cost savings over time makes this a very compelling outdoor tankless water heater indeed. With an impressive 9.0 GPM flow rate, you can easily provide hot water for the average North American home, the ability to heat 2 showers at once.

Pros

  • Most efficient on energy in the Outdoor Natural Gas category
  • Built by Rinnai, an industry leading and trusted name in water heating
  • An amazing 12 year warranty on the heat exchanger

Cons

  • Somewhat expensive up front, but not by much
  • Quite a large unit
  • Efficiency limit the absolute flow rate

We give the Rinnai RU90eN the top spot on our list for being the most efficient outdoor tankless water heater in the market!

Takagi T-D2-OS-NG Outdoor Tankless Water Heater, Natural Gas

Takagi T-D2-OS-NG Outdoor Tankless Water Heater, Natural Gas

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If you want the absolute maximum flow rate at the most affordable price, then the Takagi T-D2-OS-NG is the very best in class. With a whopping 10 GPM flow rate at a price lower than the competition, you can meet virtually any hot water need for any average home in North America. Takagi is a slightly lesser known brand, but with a solid product line across indoor and outdoor and thousands of positive online reviews, we think the name is beginning to stand side by side with Rheem and Rinnai. While you will pay less up front for this unit, it sacrifices efficiency for raw power, meaning you will pay more for energy over time.

Pros

  • Most powerful in terms of GPM rate on the outdoor category
  • Very affordable up-front price
  • Excellent 12 year heat exchanger warranty

Cons

  • Lower end of the efficiency scale at an unimpressive 82%
  • Will be more expensive over time due to more energy cost
  • Not the most visually appealing unit

If you want the highest possible flow rate for the lowest possible up-front cost, then the Takagi T-D2-OS-NG is the right model for you.

Rheem RTGH-95XLN Prestige Natural Gas Outdoor Tankless Water Heater

Rheem RTGH-95XLN Prestige Natural Gas Outdoor Whole House Low NOx Condensing Tankless 9.5 GPM Water Heater

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If you are looking for the perfect mix of power and effiency, with a trusted name in the industry, look no further than the Rheem RTGH-95XLN Prestige outdoor tankless water heater. With both a 9.5 GPM flow rate and a very impressive 94% energy efficiency, you don’t have to sacrifice power for efficiency. We also feel this unit is perfectly priced making it of tremendous value. When you have a brand name like Rheem offeing best in class efficiency with best in class flow rates, you certainly cannot go wrong with this fantastic tankless outdoor water heater.

Pros

  • One of the highest effiency outdoor units at 94%
  • One of the highest GPM flow rates at 9.5 GPM
  • Backed by leading brand and warranty

Cons

  • Slightly more expensive than the Takagi model for less flow
  • Not as attractive externally as the Rinnai Models

If you want the best of the best and are willing to spend a little more up-front, then look no further than the Rheem RTGH-95XLN Prestige.

Rinnai RL94eN Natural Gas Outdoor Tankless Water Heater

Rinnai RL94eN Natural Gas Tankless Water Heater, 9.4 Gallons Per Minute - Outdoor

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If you trust the Rinnai name but don’t want to buy their top of the line model, you can save a little bit and go with their RL94eN water heater. While not as efficient as our #1 pick on this list, you can still get that high flow rate for a lower price at the cost of efficiency. While this is a great model and we’ve included it for it’s popularity and the trust in the Rinnai name which offers a mid priced unit in the low efficiency category. Of course it comes with the warranty you would expect from Rinnai, which has it’s value, and a leading flow rate at 9.4 GPM, capable of meeting the needs of the average household.

Pros

  • One of the most trusted names in tankless water heating
  • Industry leading warranty
  • Very high flow rate at 9.4 GPM
  • Visually appealing

Cons

  • Low efficiency rate of 83% means you’ll pay more over time
  • More expensive relative to Rheem and others
  • Not the best bang for your buck in terms of value

While this is a great outdoor tankless water heater from a trusted brand, we think other models may be a better bargain if you’re not set on the Rinnai name.

Rheem RTG-84XLN Low NOx Outdoor Tankless Natural Gas Water Heater

RTG-84XLN 8.4 GPM Low NOx Outdoor Tankless Natural Gas Water Heater

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The Rheem RTG-84XLN is simply the best outdoor tankless water heaters for smaller homes. If you have 2 bathrooms or less, there isn’t much need to get a 9+ GPM unit when 8.4 will be more than enough for your needs. At a very attractive price, by a reputable brand with an industry leading warranty, any smaller home can’t go wrong with this fantastic outdoor tankless water heater from Rheem. You may not be able to heat two showers and a dishwasher at once, you’ll have to settle for just one shower and one appliance at a time. For most of us, that will do just fine. We’ve also included this Nox version which is more eco friendly and produces less emissions.

Pros

  • Adequate flow rate for the majority of homes
  • Very low emissions compared to other gas heaters
  • Very attractive price for a Rheem model

Cons

  • Slightly louder than expected
  • Low flow rate relative to price

If being eco-friendly while still having enough power for an entire house, then the Rheem RTG-84XLN is the right model for you.