Rinnai RL75iN Natural Gas Tankless Hot Water Heater, 7.5 GPM

(9 customer reviews)


Product details

Brand Rinnai
Capacity 7.5 Gallons
Power Source Gas Powered
Item Dimensions LxWxH 17.5 x 13 x 31 inches
Color Gray
Voltage 120 Volts

  • Original Design: Tankless hot water heater’s Circ-Logic technology offers recirculation patterns that match your habits; For the latest in non-condensing technology that speeds up service and installation, check out our new RE160iN model
  • Never Run Out of Hot Water with this Compact Tankless Gas Water Heater: Non-condensing tankless hot water heater from Rinnai is only the size of a small suitcase and fits in a wide variety of spaces, but provides up to 7.5 GPM (5 fixtures at once)
  • Smart, Durable Design: Includes 12-, 5-, and 1-year residential guarantee and 5-, 5-, and 1-year commercial factory warranty for heat exchanger, labor, and parts, respectively; See Controlr module for WiFi control (not included)
  • Professional Installation Recommended: Visit the Find a Rinnai PRO page on our website to locate a qualified technician in your area to install your tankless water heater; We do not recommend installing a water heater without a technician
  • Find Your Rinnai: See our product guides, manuals, energy guide, warranty information, videos, and tables to find the right tankless water heater for your home; Check our Ground Water Temperature Map to see if this heater is optimal for your region


Product Description

Rinnai’s high-efficiency non-condensing indoor tankless natural gas water heater models offer advanced technology for your home with comfort and value. Designed to be extremely compact, this small water heater only takes up the space of a small suitcase, letting you reclaim some of your home’s most valuable real estate. This smart on-demand hot water heater can be made even smarter with a Rinnai Controlr for WiFi connectivity (not included). This easy-to-install, ultra-compact unit lets you enjoy all the benefits of Rinnai tankless water heating. You’ll experience clean, reliable hot water at a consistent pre-set temperature, while saving energy and precious floor space in your home.

From the Manufacturer

Stop planning your mornings and evenings around your water heater. Set your own schedule, thanks to the R75LSi. Ideal for two- to three-bathroom homes, the R75LSi delivers up to 7.5 gallons of hot water per minute (GPM), while saving energy and money. Mount your compact R75LSi in virtually any room, and vent directly to the outside with a single wall or roof penetration.

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 54 kg
Dimensions 17.5 × 13 × 31 cm



7.5 Gallons

Power Source


Item Dimensions LxWxH

17.5 x 13 x 31 inches




120 Volts




Natural Gas Indoor Installation

Part Number


Item Weight

54 Pounds

Product Dimensions

17.5 x 13 x 31 inches

Item model number



7.5 GPM



Item Package Quantity


Water Consumption

9.4 Gallons


Energy Star


Indoor use only

Included Components

Valve Kit

Batteries Included


Batteries Required


Warranty Description

See Manufacturer



Date First Available

June 27 2011



9 reviews for Rinnai RL75iN Natural Gas Tankless Hot Water Heater, 7.5 GPM

  1. Phil

    I will never go back to a water heater with a tankI bought one (larger) for my business about 3 years ago, and I love it! When I decided to upgrade at home, I had my plumbing contractor install this one at my house. Amazing! You NEVER run out of hot water! I do live in an area with extremely hard water, so I had bypass valves installed, so I can run a cleaning solution thru it every 6 months (as recommended).Don’t run out of hot water ever again! (Mine is connected to natural gas line)You will be required to purchase Rannaii venting for this unit, as venting does NOT come with it.

  2. Core

    Owner InstallSo, here’s the deal, if your going to tackle this project yourself.. Your going to need quite a few tools.2 Adjustable wrenches, Teflon tape, measuring tape, a whole lot of patience. And some experience with plumbing. And more tools.And if you have to install a new gas line.. yeah good luck with that, you may need a plumber/ a whole lot of digging! and it will cost you a pretty penny, so I hope you saved up?For me my water heater went out. My second water heater to go out. When this second one went out, the inner liner around the relief valve went bad. And so this pin hole leak grew.. and grew, and since I thought things were just fine.. well my utility room ended up getting pissed on by my old water heater. So I had heard of tankless water heaters and of Rinnai in particular, and its Japanese quality, and decided this time around I was going to try something different.One of the big things you may forget about is the venting with this install, both the amount you need and the tools for the job.. One, depending on where you live and your buying this unit, you might get screwed vent wise. If your here on Amazon thinking about buying one, it means your probably slightly educated about new plumbing tech, and you don’t have any local dealers.The closest Rinnai dealers/service guys were like 50 miles away for me. So I decided to install this badgirl myself. Or try to. Or fail trying! I think failing while your running is the best.. because that momentum you build up before you fall face forward into failure.. thrilling and impactful!Two mistakes I made when ordering this were:1.I didn’t think of a GREAT way to cut the venting material. (I was like I have a hacksaw, should be no problem, WRONG! it was tedious at best) you really need good solid clean cuts with the venting material, because of the airtight seals the gaskets form in the material.. Like if you don’t have good clean cuts, the joining of the material will go from really annoying.. to use your imagination. )Here’s a solution! Also you can use this to cut drain pipe later on when you need to. Also it looks like there’s a long lead up time to getting the actual product for some unknown reason so if your planning ahead, may want to just go ahead and bite the bullet. Why else do you have that prime account?https://www.amazon.com/dp/B001H4NUB4/ref=twister_B00N4NUEBA?_encoding=UTF8&th=1orhttps://www.amazon.com/Ridgid-31662-4-Inch-8-Inch-Acting/dp/B001P3091Q/ref=pd_sim_469_15?_encoding=UTF8&pd_rd_i=B001P3091Q&pd_rd_r=GP12BP3ZE2BREP7SECBD&pd_rd_w=bqkeZ&pd_rd_wg=Z0EMp&psc=1&refRID=GP12BP3ZE2BREP7SECBD2.I ordered the outdoor vent termination kit right? well that’s all well and good if I had an extremely short distance to go.. But I had a foot beyond that, and also needed some 45degree elbows. And vent extensions. Spoiler! (I could not buy the vent extensions locally! no one had any… so I end up ordering those off amazon as well!- – -but after I had my new tankless water heater and had installed it and so I had to cap my cold water supply line and take a cold a$$ bath because I couldn’t vent my unit) FUN TIMES!Anyways, my knee jerk reaction on this install. It’s actually pretty straight forward. Rip out your old tank, plumb new lines in, make sure you got the correct adapters to hook up. make sure you don’t reverse your lines, label stuff, take your time.. hook it all up and it throws a fault! So the little computer in this unit worked good. Correct that issue. And good to go!It’s quiet for the most part. 120 degrees Fahrenheit in the summer time is hot enough. I may tinker with this later. Depends. I did not install a recirculating set up, I just did a straight forward install, and so I do experience that “Sandwich effect” on the water, but I had that with my hot tank water heater, so its nothing new.Works fairly quickly.Also, this unit in particular came with the Rinnai Union/Drain Valves… I ended ordering a set of Union/Drain Valves .. so now I have extra, accidentally. Just a heads up.If anything worth anything happens down the line. I’ll give an update. Or if your reading this review five years down the line and want to know how this unit has held up, just send me a request. If I still live in the same house I’ll try and reply. But not to technical questions.Good luck if your doing a self install and not a plumber. I’m very grateful my unit function great right out of the box pretty much.P.S. I wish plumbing were easier and more straightforward. Like plug and play. I have a feeling there’s a whole industry here for future new housing if someone can make it happen.Year Update + Change:Well its paid for itself now. My gas bill has been continuously cheaper, even though I completely take advantage of the continuous hot water.I’m really glad I bit the bullet & made this buy. I didn’t know how it would work out at first, but as long as I don’t overwhelm the unit, like washer filling with hot water , because washer is pulling a lot of hot water volume, while running hot water for the bath, its pretty freaking awesome!Its honestly continues to work better than I could ever have hoped for & that’s on a 1/2″ instead of 3/3″ line.

  3. M. C. Stith

    No complaints and I definitely would recommendOK… hot water stops(off and on) midstream without an obvious reason, so called for the repair guy…..1st time to do anything in almost 10 years as of 11/1/21….will update.Update as of 7/5/17…..Still great, and have had zero issues.Update as of 11/12/14…..We have had our Rinnai installed now for about 44 months and it works extremely well. There can be a delay in hot water, or a cold water sandwich; if you change temperature quickly or turn off and then on after having it on for 15 seconds or more. It probably takes 30 seconds for ours to really heat up, and maybe 40-45 seconds to get really hot water in the dead of winter…this is slower than a tank heater and the only detriment I can note or am aware of at this point. Puts out plenty of HOT water for us as we can have 2 showers and laundry going in the dead of winter…it is no problem. We adjusted our tank to put out 140 degree water and we love it…again, especially in the winter. My wife used to fill our tub, and the old water heater would actually run out of hot water(it is a large tub)…..this is never a problem again! I think beyond 3 uses at one time(shower, laundry, dishwash, etc) running you would have a capacity problem…or extrememly cold basement. There are two of us here most of the time with the occasional guests….2 1/2 bath, and Rinnai is in the basement and very close to our main shower/bathroom, so this helps the time as our upstairs shower can take a minute to get hot water when its cold. Also, getting water temp correct with a single turn knob may be an issue….the water temp only goes so low before it will cut off….but we found the minimum spot which is hot, but we turned up our Rinnai so we could get hotter water and ideally, more use or capacity at the same time. By the way it is not uncommon for our basement to be 50 or so degrees in the winter and this easily overcomes that. I cant say how much cash it has saved us really, but our propane bill has definitely not gone up…and I estimate our electric bill had actually dropped 10 bucks/mo., and that was with our electric going up 9% last year, and another 5% this year. We replaced the original house water heater that had gone bad after 6 years do to salt water getting through our reverse osmosis/charcoal filter/saline filtration system(we have very salty well water on the coast)and it backed into the original water heater due to a valve being left open….and then it literally ate our water heater from the inside out with just one soaking of brackish water(took about 6 months to destroy it, of course we didn’t know it was happening until the rust color started to show up) but once the water started turning rusty it was obviously too late(and this was only a 6 yr old water heater. Also, since we have a whole house well reverse osmosis and double charcoal filters purified water running, we shouldnt have to flush our Rinnai like you are supposed to do with these every year(our water has about 60ppm tds), but you are supposed to flush/clean every year to remove buildup and sediments(we pay enough up front to not have this issue unless our filter goes bad or salt water gets through usually by human mistake). We paid less for this than our local plumber could buy them wholesale through his supplier(by about 150 bucks total). He said there is an even more efficient tankless Rinnai available if your interested? This got here in 2 days and just make sure to order the venting pipes and gas taps if you need them! We had our whole system installed for 1350 total…..so it cost us about 500 bucks more than a good replacement standard tank water heater….I am sure we have gotten this back or will be very close by the end of this year. I believe we have saved 15 bucks per month on average? Make sure your gas pipes have enough flow…..Ive heard this can be an issue also? We really love ours. If anything happened we would probably just upgrade to the more efficient unit. Our unit is about 3 years installed now, maybe longer and I see others have issues, but we really have to recommend at this point. I will edit should anything come up as I think this needs to last at least 12 years for the return to really pay off. Propane and electricity is getting more expensive and this helps through efficiency to combat costs. Installed 03/2012

  4. John

    Replaced my older Rinnai model, but the outlet line was in a different locationLike it and would have given a 5 STAR but by manufacturing it with the outlet line 2″ one way and 1″ fwd made the installation a real problem !! Had to solder 6- 90 degree elbows and an insert piece to make it work. Wish they would keep the inlet & outlet hoses in the same spot on a newer model..

  5. Larry S2

    Cheap hot water in Ontariocheapest way to have hot water in Ontario, works well replace same unit that was a rental & rental was getting expensive so replaced it with a twin, original has given us 9 years of trouble free hot water no issues with it ever, and once you are used to how it works, for showers turn hot water on full & adjust with cold if you do that you will not get cold water unexpectedly. Also remember if you go back to use water & it’s still hot remember you will get a shot of cold in front of next batch of hot water. I strongly recommend unit.

  6. Jason D.

    Perfect alternative to renting from reliance home comfortI live in Ontario, Canada and have been renting the exact same unit from Reliance Home Comfort for the past five years. I wish I had purchased one of these a lot sooner.After purchasing this I now save $45 a month on the rental cost. I hired a gasfitter to install it.

  7. Doggerdave

    Excellent price!Great price. Installed in place of the exact model (a rental) so install was a synch. My rental provider wanted about $500 more than this brand new one for my existing 7 year old so purchasing new was a no brainer.

  8. Elizabeth P

    Wonderful water heater but remember the ventIt’s a little bigger and noiser then I would have liked but otherwise it works great and the plumber installed it no problem. REMINDER: you must also buy a vent pipe with this!

  9. Terry Phillips

    Efficient/ cost effective/ endless hot waterInfloor heating application. Run @ 160 degrees F. Added circulation pump wired to room thermostat through a relay. Excellent space saver.

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