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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 - Rinnai Universal Horizontal Termination Kit 11.5" 223181 - - Water Heater Venting - Big Frog Supply - 2
    Rinnai - Rinnai Universal Horizontal Termination Kit 11.5" 223181 - - Water Heater Venting - Big Frog Supply - 1

    Rinnai 223181 Non-Condensing Universal Horizontal Termination Kit 11.5"

    Rinnai
    $ 96.19 - $ 96.19
    $ 96.19
    $ 96.19 - $ 96.19
    $ 96.19

    Rinnai Universal Horizontal Termination Kit The Rinnai 223181 Non-Condensing Horizontal Termination Kit is an 11-1/2” universal venting solution th...

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    $ 96.19 - $ 96.19
    $ 96.19
    $ 96.19 - $ 96.19
    $ 96.19
  • Rinnai - Rinnai Universal Horizontal Termination Kit 21" 223182 - - Water Heater Venting - Big Frog Supply

    Rinnai - 223182 - Universal Horizontal Termination Kit 21"

    Rinnai
    $ 114.99 - $ 114.99
    $ 114.99
    $ 114.99 - $ 114.99
    $ 114.99

    Long 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 a...

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    $ 114.99 - $ 114.99
    $ 114.99
    $ 114.99 - $ 114.99
    $ 114.99
  • Rinnai - Rinnai Vent Pipe Extension 39" 224053 - - Water Heater Venting - Big Frog Supply

    Rinnai - 224053 - Vent Pipe Extension 39"

    Rinnai
    $ 78.00 - $ 78.00
    $ 78.00
    $ 78.00 - $ 78.00
    $ 78.00

    39" vent pipe extension for your Rinnai tankless water heater venting. Inner exhaust material is aluminum and outer intake material is plastic. Pa...

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    $ 78.00 - $ 78.00
    $ 78.00
    $ 78.00 - $ 78.00
    $ 78.00
  • Rinnai - Rinnai Vent Pipe Extension 10" 224051 - - Water Heater Venting - Big Frog Supply

    Rinnai - 224051 - Vent Pipe Extension 10"

    Rinnai
    $ 50.00 - $ 50.00
    $ 50.00
    $ 50.00 - $ 50.00
    $ 50.00

    10" vent pipe extension for your Rinnai tankless water heater venting. Inner exhaust material is aluminum and outer intake material is plastic. Pa...

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    $ 50.00 - $ 50.00
    $ 50.00
    $ 50.00 - $ 50.00
    $ 50.00
  • Rinnai - Rinnai Condensate Trap 222053 - - Water Heater Venting - Big Frog Supply
    Sold out

    Rinnai - 222053 - Condensate Trap

    Rinnai
    $ 61.00 - $ 61.00
    $ 61.00
    $ 61.00 - $ 61.00
    $ 61.00

    Rinnai has made the best condensating trap for their line of tankless water heaters. The 222053 condesate trap works with all plastic and metal com...

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    $ 61.00 - $ 61.00
    $ 61.00
    $ 61.00 - $ 61.00
    $ 61.00
    Sold out
  • Rinnai - Rinnai 18" Roof Discharge Terminal 184118S - - Water Heater Venting - Big Frog Supply

    Rinnai - 184118S - 18" (above roof) Roof Discharge Terminal

    Rinnai
    $ 115.00 - $ 115.00
    $ 115.00
    $ 115.00 - $ 115.00
    $ 115.00

    Rinnai roof discharge 18" for non-condensing ultra series tankless water heaters. SKU: 184118S Color of product may differ from image. This ventin...

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    $ 115.00 - $ 115.00
    $ 115.00
    $ 115.00 - $ 115.00
    $ 115.00
  • Rinnai - Rinnai 90 Degree Elbow 224063 - - Water Heater Venting - Big Frog Supply

    Rinnai - 224063 - 90 Degree Elbow

    Rinnai
    $ 63.00 - $ 63.00
    $ 63.00
    $ 63.00 - $ 63.00
    $ 63.00

    This 90 degree elbow is for non-condensing (luxury and value series) Rinnai tankless water heaters. Rinnai 224063. Product color may differ from im...

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    $ 63.00 - $ 63.00
    $ 63.00
    $ 63.00 - $ 63.00
    $ 63.00
  • Rinnai - Rinnai Vent Pipe Extension 19.5" 224052 - - Water Heater Venting - Big Frog Supply

    Rinnai - 224052 - Vent Pipe Extension 19.5"

    Rinnai
    $ 71.00 - $ 71.00
    $ 71.00
    $ 71.00 - $ 71.00
    $ 71.00

    19.5" vent pipe extension for your Rinnai tankless water heater venting. Inner exhaust material is aluminum and outer intake material is plastic. ...

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    $ 71.00 - $ 71.00
    $ 71.00
    $ 71.00 - $ 71.00
    $ 71.00
  • Rinnai - Rinnai 45 Degree Elbows For Venting NON CONDENSING (2 Pack) 224050 - - Water Heater Venting - Big Frog Supply

    Rinnai - 224050 - 45 Degree Elbows For Venting NON CONDENSING (2 Pack)

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

    45 degree elbows for your Rinnai tankless water heater venting. Inner exhaust material is aluminum and outer intake material is plastic. Part Numb...

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    $ 87.00 - $ 87.00
    $ 87.00
    $ 87.00 - $ 87.00
    $ 87.00

  • 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

  • Rinnai REP199iN High Efficiency Non Condensing Indoor Tankless Water Heater With Built-in Recirculation Pump

    Rinnai
    $ 1,381.59 - $ 1,381.59
    $ 1,381.59
    $ 1,381.59 - $ 1,381.59
    $ 1,381.59

    Rinnai REP199iN High Efficiency Tankless Water Heater With Recirculation Pump The Rinnai REP199iN High-Efficiency Tankless Water Heater delivers ma...

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    $ 1,381.59 - $ 1,381.59
    $ 1,381.59
    $ 1,381.59 - $ 1,381.59
    $ 1,381.59

  • Rinnai RE180iN Natural Gas High Efficiency Non Condensing Tankless Water Heater

    Rinnai
    $ 1,091.16 - $ 1,091.16
    $ 1,091.16
    $ 1,091.16 - $ 1,091.16
    $ 1,091.16

    Rinnai RE180iN Indoor Non Condensing Tankless Water Heater Enjoy endless hot water and exceptional efficiency with the Rinnai RE180iN natural gas t...

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    $ 1,091.16 - $ 1,091.16
    $ 1,091.16
    $ 1,091.16 - $ 1,091.16
    $ 1,091.16
  • 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 - RE160iP - RE Model Series High Efficiency Non Condensing (Replaces model V65)

    Rinnai
    $ 893.34 - $ 893.34
    $ 893.34
    $ 893.34 - $ 893.34
    $ 893.34

    Spec Sheet Install Manual Learn More RE160iP is the perfect combination of high efficiency, comfort and value in a Propane gas non- condensing ta...

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    $ 893.34 - $ 893.34
    $ 893.34
    $ 893.34 - $ 893.34
    $ 893.34
  • 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 - RE199iP - RE Model Series High Efficiency Non Condensing (Replaces model V94 and RL94)

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

    Spec Sheet Install Manual Learn More RE199iP is the perfect combination of high efficiency, comfort and value in a Propane gas non- condensing ta...

    View full details
    $ 1,280.79 - $ 1,280.79
    $ 1,280.79
    $ 1,280.79 - $ 1,280.79
    $ 1,280.79

  • Rinnai RE180iP High Efficiency Non Condensing Indoor Propane Tankless Water Heater

    Rinnai
    $ 1,091.16 - $ 1,091.16
    $ 1,091.16
    $ 1,091.16 - $ 1,091.16
    $ 1,091.16

    Rinnai RE180iP Indoor Propane Tankless Water Heater The Rinnai RE180iP Tankless Water Heater is your high-efficiency, space-saving solution for end...

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    $ 1,091.16 - $ 1,091.16
    $ 1,091.16
    $ 1,091.16 - $ 1,091.16
    $ 1,091.16

  • Rinnai - RE160iN - RE Model Series High Efficiency Non Condensing (Replaces model V65)

    Rinnai
    $ 893.34 - $ 893.34
    $ 893.34
    $ 893.34 - $ 893.34
    $ 893.34

    Spec Sheet Install Manual Learn More RE160iN is the perfect combination of high efficiency, comfort and value in a natural gas non- condensing ta...

    View full details
    $ 893.34 - $ 893.34
    $ 893.34
    $ 893.34 - $ 893.34
    $ 893.34
  • 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...

    View full details
    $ 84.00 - $ 84.00
    $ 84.00
    $ 84.00 - $ 84.00
    $ 84.00

  • Rinnai REP199iP High Efficiency Non Condensing Tankless Water Heater with Built-in Recirculation Pump.

    Rinnai
    $ 1,381.59 - $ 1,381.59
    $ 1,381.59
    $ 1,381.59 - $ 1,381.59
    $ 1,381.59

    Rinnai REP199iP Non Condensing Tankless Water Heater The Rinnai REP199iP Non Condensing Tankless Water Heater delivers the perfect blend of high ef...

    View full details
    $ 1,381.59 - $ 1,381.59
    $ 1,381.59
    $ 1,381.59 - $ 1,381.59
    $ 1,381.59

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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