Rinnai RU199iN Condensing Tankless Hot Water Heater, 11 GPM, Natural Gas, Indoor Installation

(10 customer reviews)


Product details

Brand Rinnai
Power Source Gas Powered
Item Dimensions LxWxH 22.05 x 14.76 x 33.86 inches
Color Silver/Grey
Voltage 120 Volts
Item Weight 74.1 Pounds

  • Endless Hot Water: Enjoy unlimited hot water flow throughout the house; compact, durable, and easy to install; professional installation recommended
  • Energy and Space Efficient: Space-saving design conserves energy as it heats only when necessary
  • Optimal Water Pressure: Up to 11 GPM hot water flow rate for a powerful, constant stream
  • Instant Heating: Equipped with Circ-Logic – Pair with an external pump to reduce wait time for hot water via scheduled or on-demand recirculation
  • Guaranteed to Last: 15-, 5-, and 1-year residential for heat exchanger, labor, and parts, respectively. Wifi monitoring.


Rinnai’s super high-efficiency plus condensing indoor tankless water heater models offer the most advanced technology with SENSEI. Unlike tank heaters which accumulate rusty sediments, this RU199iN compact tankless water heater has a longer lifespan since water runs continuously through pipes. Pair with an external pump and enjoy on-demand recirculation technology for faster and more efficient hot water delivery right out of the faucet!

From the manufacturer


tankless heater

constant hot water

lasts twice as long


Never run out of hot water again

With Rinnai, hot water is always available to you, no matter how much or how often you need it

Smarter, more durable than a tank

Rinnai tankless water heaters last up to twice as long, and save energy-heating water only when needed

The Rinnai difference

Individually tested for quality before shipping, Rinnai makes the vast majority of our key components, unlike our competitors, allowing for better, more consistent quality

energy efficient

recirculation technology

space saving design

Enjoy energy saving benefits

Rated by a Uniform Energy Factor (UEF), our tankless water heaters are highly energy efficient, saving you from expensive power and water costs

Recirculation benefits

Hot water is always ready. Our ThermaCirc360 technology can offer faster hot water through an external pump (sold separately)

Saves valuable space

Our suitcase-sized compact wall units fit neatly in, freeing up more usable areas in your home

Important information

Bulb Voltage

120 volts

Additional information

Weight 74.1 kg
Dimensions 22.05 × 14.76 × 33.86 cm


Power Source


Item Dimensions LxWxH

22.05 x 14.76 x 33.86 inches




120 Volts

Item Depth

11.45 in 290 mm


Natural Gas Indoor Installation

Part Number


Item Weight

74.1 Pounds

Product Dimensions

22.05 x 14.76 x 33.86 inches

Item model number



11 GPM


Water Heater

Installation Method

Wall Mounted

Item Package Quantity


Included Components

Water Heater

Batteries Included


Batteries Required


Warranty Description

See Manufacturer



Date First Available

May 4 2018



10 reviews for Rinnai RU199iN Condensing Tankless Hot Water Heater, 11 GPM, Natural Gas, Indoor Installation

  1. Gordon G

    Why Didn’t I Do This Sooner? Great Product, Great Support, Saves EnergyMy AO Smith tank heater rusted out after five years. I decided to make the leap to tankless.After much research, I bought the Rinnai RU199iN. Rinnai just released a new model, with an internal water pump which I highly recommend instead of the model I bought. It was not available for delivery anywhere so I purchased the older model plus the Rinnai pump kit GTK03U to recirculate the hot water. You will also need a $100 valve from Rinnai to recirculate properly – part # 107000450.I installed the heater myself. The plumber wanted $3,000 to install it. My tank heater was connected to a recirc pump and powered exhaust fan which made the install easier.Whenever I had question, the Rinnai U.S. based support was excellent. I mean excellent – helpful, patient with very short phone wait times. Usually under 2 minutes. They keep a profile so the support person can pick up where you last called them. There are also detailed YouTube’s about installing tankless heaters.Taking on the task was not without anxiety when I disconnected the old tank and drained my house’s water supply. My house has PEX plumbing instead of copper so that helped.Now, we have instant hot water. The pump comes with a WiFi module that allows you to set on/off schedules for the recirculation pump which saves energy.The unit itself is very quiet. I can only hear it when standing next to it. The fan that runs the exhaust air is also far quieter than the fan on the old tank heater. No banging sounds in the middle of the night which came from small particles that accumulated in the bottom of the tank heater.If you have a tub and use it, a tankless heater is a must have because you will have unlimited hot water to fill it and keep it warmed up.In summary it is an well built, easy to install heater with excellent support.

  2. COM

    Performs flawlesslyOne of the best purchases from Amazon I have made. Great quality easy to install and performs amazing I have a shower with 6 heads it has constant hot water and pressure huge improvement over a hot water heater and my water is fed from a glacial lake that goes in at 42 degrees and I have it set to 108 it heats the water no problem

  3. Sarah Harrison

    A good whole house water heater (beware- Amazon installers will not install this!!)2yr ownership update: Aside from one breakdown due to a faulty part (which was immediately shipped by the manufacturer under warranty) this heater is amazing. Perfectly maintained hot water temperature for as long as you need it. Can run a bath, shower and dishwasher etc and not a slightest drop in hot water pressure. Awesome! I completely recommend this heater without any hesitantion.Our home is 4 bedroom single family home with 2 main bathrooms and 2 smaller washrooms.Firstly, the positives;Fast to heat up (within 1 minutes 2 floors above)Endless flow of hot waterCan have 2 showers working and haven’t really tested how many faucets we can run at the same timeIt is quiet and does exactly what we bought it forThe only negative was the ordering process. I chose a water heater from Amazon that had a connected Amazon Installation Service option which I chose. The heater arrived quickly and in good condition. I called the Amazon approved contractor to confirm its arrival and they sent someone to come and install it. When the person came, they stated that they did not realize that it was a tankless heater and refused to install it unless they supplied it themselves. All down to Warranty issues apparently. Seeing as our existing electric tank heater had broken down2 days prior, we were left with an issue – no hot water and 3 young kids to keep bathed. I asked them to take a look at the electric heater to see if there was a fuse or something that may have gone wrong. They said that they could book the job for $150 and take a look at it but that it would most likely be the internals. (as it was, when we eventually managed to get a local installer for the new heater, he made the effort to come down and take a look at the existing heater. It was a case of taking off a small panel (4 small screws) and pressing a reset button. Sure enough, it sprang to life again)We then called Amazon to ask them to recommend another installers. The chap who dealt with us at Amazon installation services called around all the local plumbers and none of them would install a tankless heater that they had not sold. Amazon said that they would refund the installation fee and give us a $30 credit for the hassle.After a bit of phoning around we found a local plumber to do the work. I called the actual water heater manufacturer to check that the warranty would still apply and they confirmed that so long as he was a registered professional plumber then he could sign off on the warranty sheet.So the 5 stars is for the heater and only 1 star for the Amazon Installation Service

  4. daniel deville

    works great, but overkill for most housesUnless you are building a new house and have large water lines going to your faucets this may be too large. I learned after install and the hot water kept cutting off when I tried to blend some cold water in that the best way to run it is to set temp to the hottest comfortable and run your hot water tap at full blast (no cold blended) for showers. The reason for this is that average water pipes in a house can only handle 8 gal/minute flow rate, while this is trying to push 11gal/min. Also, most shower heads only push 2.5gal/min at most. So, it will choke up if you try to blend cold water into a shower. So, you can save some money and just get the smaller unit and should work fine for most houses, or do as I described above.

  5. Scott K

    Works perfectlyI went with this model because of the reviews. The unit showed up timely in perfect shape with all parts described. The install was easy with the clear instructions, took me about 6 hours. I had a 50 gallon natural gas non high efficiency go to hell so the longest part of the install was the venting. I will admit I have a lot of experience working with plumbing, gas and electrical so it was nothing I’ve never seen before. Anyone with basic handyman skills can do this install with the instructions provided. I didn’t rate the customer support only because I never needed to use it so I have no idea.

  6. D. Coral

    Tips for Error Code 12I love this tankless heater. It is also easy to maintain to keep it running rock solid over the years. I’d like to share some tips from my experience if you come across error code 12, which means that it couldn’t keep the flame alive. The first thing you should check are the flame rods. After a while some carbon deposits build up on the rods, and you can scrape it off using Scotch-Brite and it will start working again like new. Or simpler, order some spare flame rod kits and you’ll have them available next time they need replacing. They’re pretty inexpensive parts, and very easy to access using just 3 screws. On another occasion I got error code 12 because some debris on the roof blew on top of the roof vent and partially blocked the vent. I was perplexed about the cause, until I went on the roof for an unrelated roof project and saw the debris covering the vent. But most the time it will be the flame rods. Hopefully this saves someone a service visit!

  7. Sam H.

    Straightforward and easy install. Hire a pro for GAS.You really need to contact a professional for the gas installation, but the rest was very straightforward and easy to do. The hanging system for this unit is easy, though there are some mounting points that do not offer an easy hex drive access if you are mounting using hex drive screws or bolts. There are plenty of optional extras you can get to make this easier. One I opted for, being generally awful at PVC gluing and routing, was the concentric venting options, also available on here. For the RU199iN that I used you need the condensing vent. Check your model to determine what kind of venting is required for your unit.Out of the box the temperature gets high enough for most people, and the instruction manual guides the user on how to activate the extra high temperatures if necessary. I would highly suggest installing a scale inhibition system at the same time to aid with keeping the system clean.I have so much more room in my utility room it is ridiculous, not to mention having eliminated the threat of backdrafting into the house!!

  8. Jeffrey Pomeroy

    Pleased with purchase!Was fairly simple and quick to install. It was just a matter of shutting off the main water supply and gas supply, closing the isolation valves, and cutting and soldering new fittings on the copper water lines, and connecting flexible steel braided water lines with a whole house water filter. I had a 1 inch gas line already ran down the wall with a reducer to 1/2 inch so i replaced the reducer with a 3/4 and replaced the isolation valve with an additional one. Did a quick soap check to make sure there wasnt any leaks. The closet where i was installing, the studs were outside of where the mounting brackets were so i just cut up a 2×4 so that i knew that it would be mounted securely. The weird thing was that it recommended just a 2 in pvc for the exhaust port but the exhaust gases arent even hot due to the efficiency. Going through the manual i made sure to enable the setting for higher temperature, higher flow rate, and enable the service soon for 1 year and then wired it up to my automation system so that i could get statistics and so it would alarm when i needed to flush the system with vinegar. Pleased with the fact i always have water on demand.

  9. Paul H

    I will never have a tank style water heater again!This water heater is amazing and keeps up well with our household of three children and four bathrooms. It comes with the two connection valves and TP valve needed to install it. Amazon recommends that you buy the tankless heater valve installation kit, but don’t do it. It’s all there. I ended up returning the kit. The heater is well designed and has a hanging bracket that makes installation very easy. Simply locate the heater, anchor the bracket, then lift the heater up onto it. This project is not for the novice. You do need decent plumbing skills to install. It was a full day’s work by myself installing the vents and all the lines but well worth it. Don’t forget that you need to perform maintenance on these heaters every year by pumping white vinegar through the flushing valves to de-scale it. You also need to clean the intake filter. Both tasks are easy to do and well worth the benefits of this heater.

  10. NK

    Recirculation Pump and WiFi NOT INCLUDEDThe product description is misleading. “Circ-Logic technology allows you to set recirculation patterns that coincide with your typical habits. Hot water is available when you need it!” This implies there is an onboard recirculation pump, which is not the case. Also, the WiFi unit to control recirculation patterns is an additional item. The Rennai RUR series tankless water heaters contain built in recirculation pumps and WiFi control. For the RU199 you have to purchase a Grundfos GTK03 pump and a WiFi unit. We should have been informed – just like “batteries not included” – and it adds about $450 to the total cost if you want those features. Otherwise, this tankless water heater is fine. Rennai customer service, which explained all this to me, is excellent.

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