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Internet # 306655615

Model # RUCS65iN

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Super High Efficiency 6.5 GPM Residential 130,000 BTU Natural Gas Interior Tankless Water Heater

$849.00
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  • Enjoy endless hot water
  • Less space for heating gives you more space for living
  • Professional installation recommended; please call 833-746-6210
  • View More Details

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Product Details

About This Product

Welcome to ultimate efficiency. With technology that operates only when hot water is needed, super-efficient heating coils, no pilot light and no storage tank to heat and reheat water, you save on energy and utility costs. In fact, Rinnai Tankless Water Heaters use up to 40% less energy than a traditional tank water heater. Plus, with premium technology, increased energy efficiency, an improved Home Energy Rating System (HERS) Index Score and optimized LEED eligibility, our tankless solutions can increase your home's value. You can even qualify for energy efficiency rebates and tax credits. It's a smart investment for now and the future.

Highlights

  • Save time with hot water whenever and wherever you need it, any size home, even for simultaneous uses at multiple fixtures
  • Save energy and reduce utility costs by operating only when hot water is needed
  • Maximum output, minimum space; suitable for installation in non-traditional spaces such as crawl spaces and attics
  • Multiple venting options available including PVC/CPVC using the Ubbink concentric to twin pipe adaptor allow for an easy installation
  • Automatic frost protection
  • Residential warranty: limited 12-year on heat exchanger, 5-year on parts, 1-year on labor (5-year optional on labor); commercial warranty: limited 5-year on heat exchanger, 5-year on parts, 1-year on labor (2-year optional on labor)
  • *Note. Rinnai is changing the language in its warranty terms and conditions found in the current User Installation manuals. The existing statement will be replaced by the following: "This Limited Warranty applies only to products that are installed in the United States and Canada. Improper installation may void this Limited Warranty. It is recommended that a trained and qualified professional who has attended a Rinnai installation training class complete your installation." All warranties (old or new manual) will be honored as written above.
  • You can be confident in choosing to install Rinnai tankless technology in your home; our commitment to quality has made us the #1 selling tankless water heating brand in North America; your family deserves nothing less
  • Professional installation recommended; please call 833-746-6210
  • Rinnai branded accessories will ensure optimal performance of your Rinnai Tankless Water Heater.
  • For compatible isolation valve kit see Rinnai #MIVK-T-LW
  • Click here for more information on Electronic Recycling Programs
  • Return Policy
  • California residents
     see Prop 65 WARNINGS

Product Information

Internet # 306655615

Model # RUCS65iN

Specifications

Dimensions: H 26 in, W 18.5 in, D 10.1 in

Dimensions

Product Depth (in.)

10.1 in

Product Height (in.)

26 in

Product Width (in.)

18.5 in

Water Connection Size (in.)

3/4

Details

Application Type

Residential

BTU Rating

130000 Btu

Efficiency Level

High

First Hour of Delivery (gallons/hr)

228

Flow Rate @ 35°F Rise (gallons/min)

6.5 gal (US)/min

Flow Rate @ 45° Rise (gallons/min)

5.3 gal (US)/min

Gas Connection Size

3/4 in. MNPT

Gas Type

Natural Gas

Indoor/Outdoor

Indoor

Maximum Flow Rate (gallons per minute)

6.5

Number of Showers

1-2

Product Weight (lb.)

57.3 lb

Required Volt Connection

120 volt

Returnable

90-Day

Total BTU (Btu)

130000 Btu

Uniform Energy Factor

0.85

Water Heater Features

Freeze Protection, Overheat Protection, Ultra LoNox, Wall Mounted, WiFi

Water Heater Type

Gas

Warranty / Certifications

Certifications and Listings

CSA Listed

Part Warranty

5 Year

Questions & Answers

Does the water heater require electricity
ByOct 6, 2026
1 Answer | 
Answer This Question

Hi Mike, yes, all our water heaters require both gas and electric to fire up and run.

By|Oct 6, 2026


    What size is the condensate line
    BySep 7, 2026
    1 Answer | 
    Answer This Question

    Hello Ostey, The condensate drain line is 1/2 inch NPT.

    By|Sep 8, 2026


      Is this a non-condensing or condensing unit?
      ByJul 9, 2026
      1 Answer | 
      Answer This Question

      Hello AJPurnell, The RUCS65iN is a condensing unit.

      By|Aug 24, 2026

        (2)

        does it have a drain
        ByNov 26, 2024
        1 Answer | 
        Answer This Question

        Hi jess, this unit does not have an internal drain but will require a condensate drain as part of the installation. This model is a condensing unit, which means it generates condensate during operation that needs to be properly drained away to prevent damage

        By|Jul 17, 2026

          (3)

          Average cost to install a gas water heater
          ByNov 25, 2024
          1 Answer | 
          Answer This Question

          Hi Claude, we are unable to provide pricing as it varies depending on the region. You can always call around and see about companies that offer free in-home assessments with a quote for installation in your area.

          By|Nov 29, 2024


            how fast can i get hot water
            ByNov 18, 2024
            1 Answer | 
            Answer This Question

            Hi Many, it can vary by the distance from unit to the fixture you are using. It could take 30-60 seconds and in rare cases up to 5 minutes. However, once you get hot water it will be endless. Recirculation can almost instant hot water by allowing the unit to preheat the water utilizing the existing plumbing.

            By|Nov 22, 2024


              Does this need a gas regulator and if so what kind
              ByNov 9, 2024
              1 Answer | 
              Answer This Question

              Hi Tereasa, yes our tankless water heaters typically requires a gas regulator to ensure safe and consistent gas pressure. For this type of high-efficiency tankless water heater, a 2-stage gas regulator is often recommended, which provides a more stable pressure suitable for high-demand appliances. The required gas pressure specifications should be noted in the heater’s manual, but most natural gas units operate within a pressure range of 4–10 inches water column (WC). Always consult our product manual or a licensed professional for exact regulator type and installation guidance to ensure proper performance and safety.

              By|Nov 11, 2024


                Can I use the exhaust flue from the hot water tank i removed that runs up and out the roof
                ByOct 22, 2024
                1 Answer | 
                Answer This Question

                Hi Robert, we recommend you confirm with your installer and in our manual. Most existing venting will not be compatible with our units.

                By|Oct 23, 2024


                  Viewing 1-8 of 47

                  Customer Reviews

                  4.3 out of 5

                  • 4.3 out of 128 reviews
                  • 80% recommend this product
                  Filter by:
                  Showing 1-10 of 128 reviews
                  This unit is amazing! The HD price was hard to beat anywhere, and even the installer was impress...
                  This unit is amazing! The HD price was hard to beat anywhere, and even the installer was impressed. I went with this unit as the low end of the Top of the Line RUCS condensing units. The Rinnai quality is amazing and with a certified installer I found the replacement of the boiler to be the single best home improvement I've done. Hot water does take 30 secs to 1 minute to show at the faucet depending on where in the house I need it, but once it starts flowing there is nothing quite like it! The Rinnai unit is attic mounted and I hear no mechanism noise and haven't seen any undesirable side effects. This 7.5 unit can run both showers and the kitchen sink and my HE washing machine a the same time. I literally cat imagine going back to a tank heater now, and its only been installed for a week. If you have natural gas already heating your water this is the ONLY way to go. And with the special pricing it will show a much earlier return on investment for me!
                  by
                  • Verified Purchase
                  • Recommended
                  16 found this review helpful
                  Why did I wait so long?
                  Endless hot water! It's been installed for about a year. Wanted to put one in for a long time and finally pulled the trigger. The only thing I would change is the size of it as far as output(BTU). Here in Missouri the ground water temperature gets pretty low in the winter which affects the amount of GPM. If 2 or more things are demanding hot water, it struggles to keep up because of the temperature rise required . Other than that I have no complaints. It's not really a complaint but, a better and/or more flexible way to change the temperature without buying the expensive controller. I think that should be standard on all models.
                  by
                    This is an excellent tankless water heater.
                    It was easy to install and doesn't take up very much room. I have only had it for 6 months, but so far, so good. I do not have any complaints so far.
                    by
                      Rinnai On-Demand Water Heater
                      Easy replacement but hard to locate on the shelfs.
                      by
                        This customer chose to rate the product and not provide text.
                        by
                        • Verified Purchase
                        Returned Unit - Goes to sleep overnight
                        I want to follow up on initial review and comment from Rinnai "Expert". I removed the malfunctioning Rinnai and returned to store. Installed a Rheem which is working perfectly so far. In addition to the installer trying to get help with them over the phone I also tried their chat line. They where of no help and would only provide contact information for other installers and recommended I had one of them come over to wait on phone to troubleshoot. They could not even schedule an appointment! So the Rinnai "expert" does not even know how their customer support system works, or in my case didn't work
                        by
                        Response from Rinnai Product ExpertJan 22, 2025
                        We apologize for any confusion regarding our services. As a manufacturer, Rinnai does not have technicians who work directly for us. Instead, our team refers customers to licensed professionals in their area who can provide onsite troubleshooting and resolve any issues with your product.

                        Our chat team is available to assist with general questions, pro recommendations, warranty inquiries, Wi-Fi support, and product recommendations. You can reach us via the chat feature on rinnai.us Monday through Friday, 8 AM–8 PM EST. For licensed professionals, our technical support team is available 24/7 at 1-800-621-9419.

                        We appreciate your feedback and hope to provide you with the support you nee RinnaiAmerica
                          Solid directions and performance
                          Instructions provided were superb. There's a lot to consider going from a tank to tankless water heater. I took my time and everything worked out great.
                          by
                            Very happy customer
                            Savings on heated water, the space saving, one month, beyond my expectations.
                            by
                              Unit is great when it works. Problem is that you have to cycle the power every morning to get it to work. It goes to sleep over night and won't kick on in the morning. Rinnai customer support is worthless. Had installer with 25 yr experience and he can't explain why it won't work. Looks like problem with flow control valve sensor or circuit board. Rinnai tech support had him on hold for 2 hrs. They won't support the warranty either, everything is on your dime to troubleshoot what is obviously a defective unit. I'm very frustrated. Now I have to have this unit removed, return to Home Depot and get another brand installed.
                              by
                              Response from Rinnai Product ExpertJan 9, 2025
                              Thank you for sharing your feedback. I’m sorry to hear about the difficulties you’ve experienced with your Rinnai unit and our support team. The issue you’ve described is not typical, and I understand how frustrating this must be.

                              To address your concerns, I recommend reaching out to our live chat team on the Rinnai.us portal. A REAL person can respond within minutes. They can review your case in detail, provide real-time assistance, and work to resolve this matter as quickly as possible.

                              Your satisfaction is very important to us, and we’re here to help ensure your unit operates as it should. RinnaiAmerica
                              • Verified Purchase
                              1 found this review helpful
                              The water heater seems fine, ask me again in a year. But, I made a big mistake in letting Home Depot refer me to a qualified plumber. It appears that the plumbing company, ARS, jacked up the price to cover what they pay to Home Depot. The plumbers that arrived, though competent, had never installed a Rinnai. I was not aware that the installation contract was with Home Depot. My advice: find a plumber, get a quote, and then order your tankless water heater.
                              by
                              • Verified Purchase
                              Showing 1-10 of 128 reviews

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                              Product Snapshot

                              Ideal for homeowners wanting continuous hot water, ensuring energy savings and comfort.
                              Ideal for customers who want continuous hot water for multiple fixtures, ensuring energy savings.
                              Ideal for small to medium homes looking for on-demand hot water, ensuring maximum output with minimum space.
                              Ideal for small to medium homes looking for on-demand hot water, this heater boasts high efficiency and Wi-Fi connectivity for ultimate convenience.

                              Flow Rate

                              6.5 GPM
                              6.5 GPM
                              5.3 GPM
                              6.6

                              Temperature Control

                              Wi-Fi Enabled

                              Recirculation Pump

                              Multiple Water Outlets