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Whole Home Tankless Water Heaters

Whole-home tankless water heaters deliver endless hot water with compact, energy-smart designs. Shop natural gas/propane and high-output electric models, in indoor or outdoor versions, with options for built-in recirculation, Wi-Fi/app control, and clean concentric or twin-pipe venting. Finish installs with vent kits, isolation/flush valves, filters, and maintenance parts.

Shop by need

  • Fuel & power: Natural Gas (NG), Propane (LP), or 240V electric
  • Location: Indoor (vented) or Outdoor (climate/permitted)
  • Type: Condensing (highest efficiency) or Non-condensing
  • Recirculation: built-in pump models, recirc-ready units, or add-on kits
  • Venting: concentric or 2-pipe (PVC/CPVC/PP as specified) with terminations and pipe covers
  • Kits & parts: isolation/flush valves, condensate neutralizers, controllers/Wi-Fi modules, filters, and service parts

Quick choosing guide

  1. Size by demand: total your peak fixtures and calculate required GPM at your winter temperature rise. Whole-home gas units typically cover multi-bath demand; electric whole-home requires adequate amperage and is climate-dependent.
  2. Pick fuel & service: verify gas meter/line capacity and regulator for NG/LP models, or panel amperage/breaker space for electric.
  3. Choose location: Indoor where you can vent; Outdoor where climate/clearances allow and venting is impractical.
  4. Efficiency & condensate: condensing units save energy—plan a drain and consider a condensate neutralizer.
  5. Faster hot water: select a built-in recirc model or add a recirc kit/crossover; set schedules to cut wait time.
  6. Complete the kit: vent kit/terminations, isolation/flush valves, controller or Wi-Fi, and inlet water filtration/scale control as needed.
  7. Maintenance: flush/descale periodically (more often with hard water) to protect the heat exchanger.


  •

    Rinnai - RWMKT01P - Control-R Wireless Demand Recirculation Kit (Pump+Push Button)

    Rinnai
    $ 626.00 - $ 626.00
    $ 626.00
    $ 626.00 - $ 626.00
    $ 626.00

    Rinnai Control-R Wi-Fi Module and mobile app no longer are compatible w/ the RUCS/RUS Tankless Water Heaters Rinnai Control-R Kit with Push-Butto...

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    $ 626.00 - $ 626.00
    $ 626.00
    $ 626.00 - $ 626.00
    $ 626.00

  • Rinnai Bottom plate for Pipe Cover 109001364 Fits Sensei RX

    Rinnai
    $ 0.00 - $ 0.00
    $ 0.00
    $ 67.00
    $ 67.00 - $ 67.00
    $ 67.00

    Rinnai Bottom plate for Pipe Cover  109001364 Fits Sensei RX

    $ 0.00 - $ 0.00
    $ 0.00
    $ 67.00
    $ 67.00 - $ 67.00
    $ 67.00

  • Rinnai - 227412NPP - 2/4 Condensing Vertical Starter Adapter

    Rinnai
    $ 56.00 - $ 56.00
    $ 56.00
    $ 56.00 - $ 56.00
    $ 56.00

    Rinnai 2/4 Condensing Vertical Starter Adapter Weight: 1.39lbs Height: 5.63" Width: 5.71" Depth: 9.92"

    $ 56.00 - $ 56.00
    $ 56.00
    $ 56.00 - $ 56.00
    $ 56.00

  • Rinnai - 229012NPP - 12 Inch 2/4 Condensing Horizontal Termination Kit

    Rinnai
    $ 72.99 - $ 72.99
    $ 72.99
    $ 72.99 - $ 72.99
    $ 72.99

    2/4 Cond Horiz Termination Kit 12in Brand Model Compatibility SE+ Tankless Water Heaters and M-Series Boilers Diameter 4 in Lengt...

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    $ 72.99 - $ 72.99
    $ 72.99
    $ 72.99 - $ 72.99
    $ 72.99

  • Rinnai RX199iN Sensei Condensing Indoor/Outdoor Natural Gas/Propane Tankless Water Heater

    Rinnai
    $ 0.00 - $ 0.00
    $ 0.00
    $ 1,703.10
    $ 1,703.10 - $ 1,703.10
    $ 1,703.10

    Rinnai Sensei RX199iN Indoor/Outdoor Tankless Water Heater Rinnai introduces their Pro Build RX Series Tankless Water Heaters, featuring Adaptive G...

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    $ 0.00 - $ 0.00
    $ 0.00
    $ 1,703.10
    $ 1,703.10 - $ 1,703.10
    $ 1,703.10

  • Rinnai - 229013NPP - 2/4 21 Inch Condensing Horizontal Termination Kit

    Rinnai
    $ 81.00 - $ 81.00
    $ 81.00
    $ 81.00 - $ 81.00
    $ 81.00

    2 in. / 4 in. condensing horizontal termination kit 21 in. For use with Sensei Se+ tankless water heaters (condensing) and m-series boilers White ...

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    $ 81.00 - $ 81.00
    $ 81.00
    $ 81.00 - $ 81.00
    $ 81.00

  • Rinnai HVENT-2 DiversiTech Horizontal 2" Termination Vent

    Rinnai
    $ 34.97 - $ 34.97
    $ 34.97
    $ 34.97 - $ 34.97
    $ 34.97

    2 Inch Horizontal Vent Termination The DiversiTech HVENT-2 2-inch Horizontal Termination Kit is the premium solution for cleanly venting high-effic...

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    $ 34.97 - $ 34.97
    $ 34.97
    $ 34.97 - $ 34.97
    $ 34.97

  • Rinnai - 229230NPP - 10 in. 2/4 Condensing 90 Degree Elbow for Tankless Water Heaters

    Rinnai
    $ 24.25 - $ 24.25
    $ 24.25
    $ 24.25 - $ 24.25
    $ 24.25

    2/4 Condensing Vent Pipe Extension 10 in For Sensei Models Product Weight: 0.57 Height: 5.9" Width: 4.33" Depth: 6.29" Refer to the R...

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    $ 24.25 - $ 24.25
    $ 24.25
    $ 24.25 - $ 24.25
    $ 24.25
  • Rinnai - Rinnai Multi Unit Control kit REU-MSB-M - - Water Heater Controllers - Big Frog Supply

    Rinnai - REU-MSB-M - Multi Unit Control kit

    Rinnai
    $ 235.00 - $ 235.00
    $ 235.00
    $ 235.00 - $ 235.00
    $ 235.00

    Rinnai Multi Unit Control kit REU-MSB-M For use with Rinnai tankless water heaters. Electronically connects 3 tankless water heaters and allows the...

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    $ 235.00 - $ 235.00
    $ 235.00
    $ 235.00 - $ 235.00
    $ 235.00

  • Rinnai - 187595NPP - 2in x 2/4 Condensing Twin Pipe Adaptor

    Rinnai
    $ 92.00 - $ 92.00
    $ 92.00
    $ 92.00 - $ 92.00
    $ 92.00

    Features: Twin pipe adapter 2 in. x 2/4 Dimensions: 5.67 in. x 9.92 in. x 14.4 in. Water heater accessory For use with SENSEI SE+ tankless water h...

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    $ 92.00 - $ 92.00
    $ 92.00
    $ 92.00 - $ 92.00
    $ 92.00

  • Rinnai - RWMTS01 - Control-R Wi-Fi Temperature Sensor

    Rinnai
    $ 159.95 - $ 159.95
    $ 159.95
    $ 159.95 - $ 159.95
    $ 159.95

    Wireless Temperature Sensor The sensor turns off the recirculation and is available for purchase if required by local building codes.

    $ 159.95 - $ 159.95
    $ 159.95
    $ 159.95 - $ 159.95
    $ 159.95

  • Rinnai - HVENT-3 - DiversiTech Horizontal 3" Termination Vent

    Rinnai
    $ 34.97 - $ 34.97
    $ 34.97
    $ 34.97 - $ 34.97
    $ 34.97

    Horizontal 3" Termination Vent Horizontal vent kits for use in venting high efficiency fossil fuel appliances. The low profile kit hides the vent f...

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    $ 34.97 - $ 34.97
    $ 34.97
    $ 34.97 - $ 34.97
    $ 34.97

  • Rinnai - RWMKT03P - Control-R Wireless Demand Recirculation Kit (Pump+Push Button,Temp Sensor)

    Rinnai
    $ 806.00 - $ 806.00
    $ 806.00
    $ 806.00 - $ 806.00
    $ 806.00

    Rinnai Control-R Wi-Fi Module and mobile app no longer are compatible w/ the RUCS/RUS Tankless Water Heaters Rinnai Control-R Kit with Push-Butto...

    View full details
    $ 806.00 - $ 806.00
    $ 806.00
    $ 806.00 - $ 806.00
    $ 806.00
  • Rinnai - Rinnai Shingle Roof Flashing (8/12 to 16/12 pitch) 189952 - - Water Heater Venting - Big Frog Supply - 2
    Sold out

    Rinnai - 189952 - Shingle Roof Flashing (8/12 to 16/12 pitch)

    Rinnai
    $ 87.00 - $ 87.00
    $ 87.00
    $ 87.00 - $ 87.00
    $ 87.00

    Precisely engineered accessories can add even more reliability, convenience and flexibility to Rinnai Tankless Water Heaters. With Rinnai Common Ve...

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    $ 87.00 - $ 87.00
    $ 87.00
    $ 87.00 - $ 87.00
    $ 87.00
    Sold out

  • Rinnai - 229205NPP - Condensing 2/4 45 Degree Elbow (2 Pack) for Tankless Water Heaters 229205NPP

    Rinnai
    $ 50.75 - $ 50.75
    $ 50.75
    $ 50.75 - $ 50.75
    $ 50.75

    For use with Sensei Se+ tankless water heaters (condensing) and m-series boilers. Refer to the Rinnai Water Heater Installation and Operation man...

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    $ 50.75 - $ 50.75
    $ 50.75
    $ 50.75 - $ 50.75
    $ 50.75

  • Rinnai RX160iN Sensei RX Series Indoor/Outdoor Natural Gas/Propane Tankless Water Heater

    Rinnai
    $ 0.00 - $ 0.00
    $ 0.00
    $ 1,442.70
    $ 1,442.70 - $ 1,442.70
    $ 1,442.70

    Rinnai Sensei RX160iN Natural Gas/Propane Tankless Water Heater Rinnai RX160iN Tankless Water Heater features Adaptive Gas Valve Technology that al...

    View full details
    $ 0.00 - $ 0.00
    $ 0.00
    $ 1,442.70
    $ 1,442.70 - $ 1,442.70
    $ 1,442.70

  • Rinnai RE140iP Propane Indoor High Efficiency Non Condensing Tankless Water Heater

    Rinnai
    $ 795.69 - $ 795.69
    $ 795.69
    $ 795.69 - $ 795.69
    $ 795.69

    Rinnai RE140iP Indoor Tankless Water Heater The Rinnai RE140iP  High Efficiency Tankless Water Heater is the ideal indoor solution for homeowners s...

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    $ 795.69 - $ 795.69
    $ 795.69
    $ 795.69 - $ 795.69
    $ 795.69

  • Rinnai V53DeN V Series High Efficiency Tankless Water Heater

    Rinnai
    $ 667.49 - $ 667.49
    $ 667.49
    $ 667.49 - $ 667.49
    $ 667.49

    Rinnai V53DeN High Efficiency Water Heater Experience the perfect combination of efficiency and value with the Rinnai V53DeN Non-Condensing Tankles...

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    $ 667.49 - $ 667.49
    $ 667.49
    $ 667.49 - $ 667.49
    $ 667.49

  • Rinnai - 710342 - 3/5 Rubber Wall Plate White

    Rinnai
    $ 9.00 - $ 9.00
    $ 9.00
    $ 9.00 - $ 9.00
    $ 9.00

    Rubber Wall Plate (White) Wall Plate for Rinnai's unique Ubbink concentric venting system provides ease of installation. Compatible with all indoo...

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    $ 9.00 - $ 9.00
    $ 9.00
    $ 9.00 - $ 9.00
    $ 9.00

  • Rinnai - 242141 - Flashing for Metal Roof - Plastic

    Rinnai
    $ 108.98 - $ 108.98
    $ 108.98
    $ 108.98 - $ 108.98
    $ 108.98

    Flashing for Metal Roof For metal roof installations. Zero clearance to combustibles. Material: Plastic UPC: 8713645120461 Height: 2.5" Width...

    View full details
    $ 108.98 - $ 108.98
    $ 108.98
    $ 108.98 - $ 108.98
    $ 108.98

  • Rinnai RXP160IN Sensei RX Condensing Recirculating Pro Series Indoor with Pump Natural Gas/Propane

    Rinnai
    $ 0.00 - $ 0.00
    $ 0.00
    $ 1,685.60
    $ 1,685.60 - $ 1,685.60
    $ 1,685.60

    Rinnai RXP160iN – Sensei RX Series Indoor Tankless Water Heater The Rinnai RXP160iN is built for homeowners who want dependable performance, intell...

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    $ 0.00 - $ 0.00
    $ 0.00
    $ 1,685.60
    $ 1,685.60 - $ 1,685.60
    $ 1,685.60

  • Rinnai RX180iN Sensei Indoor/Outdoor Tankless Water Heater Natural Gas/Propane

    Rinnai
    $ 0.00 - $ 0.00
    $ 0.00
    $ 1,566.60
    $ 1,566.60 - $ 1,566.60
    $ 1,566.60

    Rinnai RX180iN – Sensei RX Series Indoor Tankless Water Heater The Rinnai RX180iN delivers powerful, efficient hot water performance for medium-to...

    View full details
    $ 0.00 - $ 0.00
    $ 0.00
    $ 1,566.60
    $ 1,566.60 - $ 1,566.60
    $ 1,566.60

  • Rinnai RE199iN Natural Gas High Efficiency Non Condensing Tankless Water Heater

    Rinnai
    $ 1,280.79 - $ 1,280.79
    $ 1,280.79
    $ 1,280.79 - $ 1,280.79
    $ 1,280.79

    Rinnai RE199iN Natural Gas Tankless Water Heater Never run out of hot water again with the Rinnai RE199iN natural gas non-condensing tankless water...

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    $ 1,280.79 - $ 1,280.79
    $ 1,280.79
    $ 1,280.79 - $ 1,280.79
    $ 1,280.79
  • Sold out

    Rinnai CX199iN SENSEI Commercial Condensing Indoor/Outdoor Tankless Water Heater 199000 BTU

    Rinnai
    $ 0.00 - $ 0.00
    $ 0.00
    $ 1,752.80
    $ 1,752.80 - $ 1,752.80
    $ 1,752.80

    Rinnai CX199iN SENSEI Commercial Indoor/Outdoor Tankless Water Heater For commercial spaces demanding peak performance and efficiency, the Rinnai C...

    View full details
    $ 0.00 - $ 0.00
    $ 0.00
    $ 1,752.80
    $ 1,752.80 - $ 1,752.80
    $ 1,752.80
    Sold out

Pro tips: Size from the coldest inlet temperature, verify gas line and meter capacity (or electrical service for electric units), and map the vent path before mounting. Neutralize condensate on condensing models, install isolation valves for easy flushing, and follow local code for gas/electrical and combustion air. Not sure which unit or kit fits? Tell us fuel type, location, and demand—we’ll build a dialed-in list.

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