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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 - 229309NPP - 2 in. / 4 in. x 19.5in. Plastic Condensing Vent Pipe Extension Kit

    Rinnai
    $ 29.99 - $ 29.99
    $ 29.99
    $ 29.99 - $ 29.99
    $ 29.99

    Concentric venting allows for secure connection 2 in. / 4 in. condensing vent pipe extension 19.5 in For use with Sensei Se+ tankless water heater...

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    $ 29.99 - $ 29.99
    $ 29.99
    $ 29.99 - $ 29.99
    $ 29.99
  • Sold out

    Rheem - RTG20282- 3 in. x 5 in. Vertical Concentric Termination Vent Kit Stainless Steel for Mid Efficiency Tankless Gas Water Heaters

    Rheem
    $ 207.26 - $ 207.26
    $ 207.26
    $ 207.26 - $ 207.26
    $ 207.26

    3 in. x 5 in. Vertical concentric vent kit for use with the Rheem EcoSense mid efficiency indoor tankless gas units. Contains a storm collar, 6/1...

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    $ 207.26 - $ 207.26
    $ 207.26
    $ 207.26 - $ 207.26
    $ 207.26
    Sold out

  • 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

  • Rheem - RTG20271- 90 Degree elbow for RTG-64DVL, RTG-84DVL, RTG-95DVL Tankless Models

    Rheem
    $ 99.90 - $ 99.90
    $ 99.90
    $ 99.90 - $ 99.90
    $ 99.90

    3 Inch / 5 Inch Concentric Venting 90 Degree elbow for tankless models: RTG-64DVL RTG-84DVL RTG-95DVL

    $ 99.90 - $ 99.90
    $ 99.90
    $ 99.90 - $ 99.90
    $ 99.90

  • 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 - 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 - 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
  • Sold out

    Rheem - RTG20151D-1 - 36" Pipe length for RTG-64DVL, RTG-84DVL, RTG-95DVL Tankless Models

    Rheem
    $ 110.30 - $ 110.30
    $ 110.30
    $ 110.30 - $ 110.30
    $ 110.30

    36" Pipe length for Tankless Models: RTG-64DVL RTG-84DVL RTG-95DVL For 3 in. / 5 in. Concentric Tankless Venting

    $ 110.30 - $ 110.30
    $ 110.30
    $ 110.30 - $ 110.30
    $ 110.30
    Sold out
  • 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

  • Rheem - RTG20270B- 12" Pipe length for RTG-64DVL, RTG-84DVL, RTG-95DVL Tankless Models

    Rheem
    $ 44.99 - $ 44.99
    $ 44.99
    $ 44.99 - $ 44.99
    $ 44.99

    12" Pipe length for Tankless Models: RTG-64DVL RTG-84DVL RTG-95DVL For 3 in. / 5 in. Concentric Tankless Venting

    $ 44.99 - $ 44.99
    $ 44.99
    $ 44.99 - $ 44.99
    $ 44.99

  • Rheem - RTG20270C- 24" Pipe length for RTG-64DVL, RTG-84DVL, RTG-95DVL Tankless Models

    Rheem
    $ 55.99 - $ 55.99
    $ 55.99
    $ 55.99 - $ 55.99
    $ 55.99

    24" Pipe length for Tankless Models: RTG-64DVL RTG-84DVL RTG-95DVL 23.66 in. overall length For 3 in. / 5 in. Concentric Tankless Venting

    $ 55.99 - $ 55.99
    $ 55.99
    $ 55.99 - $ 55.99
    $ 55.99

  • 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...

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    $ 108.98 - $ 108.98
    $ 108.98
    $ 108.98 - $ 108.98
    $ 108.98

  • Rheem - RTG20321- Concentric 45 Degree elbow for RTG-64DVL, RTG-84DVL, RTG-95DVL Tankless Models

    Rheem
    $ 85.99 - $ 85.99
    $ 85.99
    $ 85.99 - $ 85.99
    $ 85.99

    Stainless Steel Concentric 45° elbow for use with a mid efficiency tankless gas unit installation. Perfect for making offsets in the vent run from ...

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    $ 85.99 - $ 85.99
    $ 85.99
    $ 85.99 - $ 85.99
    $ 85.99
  • Rinnai - Rinnai Horizontal Termination Diverter Kit 21" 223187 - - Water Heater Venting - Big Frog Supply
    Sold out

    Rinnai - 223187 - Horizontal Termination Diverter Kit 21"

    Rinnai
    $ 117.00 - $ 117.00
    $ 117.00
    $ 117.00 - $ 117.00
    $ 117.00

    Raised termination kit for Rinnai tankless water heater venting in the shape of an L to go outside of side wall. Inner exhaust material is aluminum...

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    $ 117.00 - $ 117.00
    $ 117.00
    $ 117.00 - $ 117.00
    $ 117.00
    Sold out
  • Rinnai - Rinnai Metal Pass Through Venting Plate 224097 - - Water Heater Venting - Big Frog Supply
    Sold out

    Rinnai - 224097 - Metal Pass Through Venting Plate

    Rinnai
    $ 32.50 - $ 32.50
    $ 32.50
    $ 32.50 - $ 32.50
    $ 32.50

    Rinnai has the best metal pass through plate for your venting needs. The Rinnai 224097 is suitable for use with plastic and metal components. Actua...

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    $ 32.50 - $ 32.50
    $ 32.50
    $ 32.50 - $ 32.50
    $ 32.50
    Sold out
  • Sold out

    Rinnai - 790146 - Check Valve PPTL to PVC Direct Vent

    Rinnai
    $ 0.00 - $ 0.00
    $ 0.00
    $ 212.19
    $ 212.19 - $ 212.19
    $ 212.19

    PVC AND CPVC COMMON VENTING IN 3" AND 4" SIZING INCREASES SAVINGS AND FLEXIBILITY AVAILABLE WITH RINNAI INLINE TANKLESS RACK SYSTEMS (TRS) AND CORN...

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    $ 0.00 - $ 0.00
    $ 0.00
    $ 212.19
    $ 212.19 - $ 212.19
    $ 212.19
    Sold out

  • Rheem - SP20286 - Horizontal Vent Termination Kit 3 In.

    Rheem
    $ 30.88 - $ 30.88
    $ 30.88
    $ 30.88 - $ 30.88
    $ 30.88

    Rheem SP20286 3" Low Profile Horizontal Termination Kit 3" Low Profile Horizontal Termination. 3 in. horizontal vent termination kit for high effi...

    View full details
    $ 30.88 - $ 30.88
    $ 30.88
    $ 30.88 - $ 30.88
    $ 30.88
  • Rinnai - Rinnai All-Weather Wall Discharge 223159 - - Water Heater Venting - Big Frog Supply

    Rinnai - 223159 - All-Weather Wall Discharge

    Rinnai
    $ 79.99 - $ 79.99
    $ 79.99
    $ 79.99 - $ 79.99
    $ 79.99

    Rinnai's all-weather wall discharge 223159. Product color may vary from displayed image.

    $ 79.99 - $ 79.99
    $ 79.99
    $ 79.99 - $ 79.99
    $ 79.99
  • Rinnai - Rinnai 21" Universal Non-Cond Horizontal Termination 223184 - - Water Heater Venting - Big Frog Supply

    Rinnai - 223184 - 21" Universal Non-Cond Horizontal Termination

    Rinnai
    $ 84.00 - $ 84.00
    $ 84.00
    $ 84.00 - $ 84.00
    $ 84.00

    Rinnai's 223184 21" universal non-condensing horizontal termination kit is compatible with all Rinnai tankless water heater models except the 98 se...

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    $ 84.00 - $ 84.00
    $ 84.00
    $ 84.00 - $ 84.00
    $ 84.00

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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