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Tankless Water Heaters

Tankless water heaters deliver endless hot water with compact, energy-smart designs. Shop gas (natural gas or LP) and electric models from Rinnai, Rheem, Stiebel Eltron, Eemax, and Chronomite—plus venting, recirculation, controls, and repair parts to finish the job.

Shop by need

  • Fuel & power: Natural Gas and Propane; Electric 120V or 240V point-of-use and whole-home
  • Model type: Condensing and Non-condensing; Indoor or Outdoor; Combination units
  • Recirculation: built-in recirc pump models, add-on pumps, pump hardware, controllers, and WiFi control accessories
  • Venting: concentric and twin-pipe kits, terminations, pipe covers, and heater guards
  • Kits & parts: NG/LP conversion kits, descaler/flush kits, repair parts, cables, and accessories
  • Series callouts: Rinnai Sensei CX and Sensei RX series options
  •

    Rinnai - 229308NPP - 2 in. / 4 in. x 10 in. Plastic Condensing Vent Pipe Extension Kit

    Rinnai
    $ 33.79 - $ 33.79
    $ 33.79
    $ 33.79 - $ 33.79
    $ 33.79

    Concentric venting allows for secure connection 2 in. / 4 in. condensing vent pipe extension 10 in For use with Sensei Se+ tankless water heaters ...

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    $ 33.79 - $ 33.79
    $ 33.79
    $ 33.79 - $ 33.79
    $ 33.79

  • Rinnai - CVENT3 - DiversiTech Concentric 3" Vent Termination

    Rinnai
    $ 49.58 - $ 49.58
    $ 49.58
    $ 49.58 - $ 49.58
    $ 49.58

    Concentric 3" Vent Termination  The DiversiTech 3-inch Concentric Vent Kit is the solution for simplifying high-efficiency furnace installations. T...

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    $ 49.58 - $ 49.58
    $ 49.58
    $ 49.58 - $ 49.58
    $ 49.58
  • White water heater with digital display and control panel on a white background
    White water heater with digital display and control panel on a white background
    Sold out

    Stiebel Eltron Tempra 20 Plus Electric Tankless Water Heater | 19.2 kW

    Stiebel Eltron
    $ 729.00 - $ 729.00
    $ 729.00
    $ 729.00 - $ 729.00
    $ 729.00

    Stiebel Eltron Tempra 20 Plus Tankless Electric Water Heater Brand: Stiebel Eltron SKU: TEMPRA 20 PLUS Product Details The Stiebel Eltron Tem...

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    $ 729.00 - $ 729.00
    $ 729.00
    $ 729.00 - $ 729.00
    $ 729.00
    Sold out

  • Stiebel Eltron - SHC6MINITANK - 235089 SHC 6 Mini-Tank Electric Water Heater, 6 Gallon, 1300W, 120V, 15-1/8" W x 20-1/2" H x 15" D

    Stiebel Eltron
    $ 269.99 - $ 269.99
    $ 269.99
    $ 269.99 - $ 269.99
    $ 269.99

    Spec Sheet Install Manual SHC series mini-tank electric water heater is ideal for office buildings, stores, malls, warehouses, food trucks, resta...

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    $ 269.99 - $ 269.99
    $ 269.99
    $ 269.99 - $ 269.99
    $ 269.99

  • Rinnai - 103000078 - Natural Gas to LP Gas Conversion Kit for RU180i Tankless Water Heater

    Rinnai
    $ 45.00 - $ 45.00
    $ 45.00
    $ 45.00 - $ 45.00
    $ 45.00

    Quick-n Easy Gas Conversion Remove 3 screws, change the orifice, parameter, and apply the new data plate Model Compatibility Conversion NG LPG...

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    $ 45.00 - $ 45.00
    $ 45.00
    $ 45.00 - $ 45.00
    $ 45.00

  • 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
  • Eemax FlowCo tankless electric water heater with FlowCo branding
    Eemax FlowCo tankless electric water heater front view

    Eemax HomeAdvantage II HA011240 Tankless Electric Water Heater | 11kW 240V SPEX75 FlowCo 240V Tankless Electric Water Heater | 7.5kW

    Eemax
    $ 0.00 - $ 0.00
    $ 0.00
    $ 260.36
    $ 260.36 - $ 260.36
    $ 260.36

    Eemax SPEX75 FlowCo Non-Thermostatic Tankless Electric Water Heater Brand: Eemax SKU: SPEX75 Product Details The Eemax SPEX75 FlowCo is a hig...

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    $ 0.00 - $ 0.00
    $ 0.00
    $ 260.36
    $ 260.36 - $ 260.36
    $ 260.36

  • Stiebel Eltron - SHC2.5MINITANK - 233219 2.5 gallon, 1300W, 120V SHC 2.5 Mini-Tank Electric Water Heater

    Stiebel Eltron
    $ 219.00 - $ 219.00
    $ 219.00
    $ 219.00 - $ 219.00
    $ 219.00

    Spec Sheet Install Manual Stiebel Eltron 233219 Details If you're storing 30+ gallons of hot water in a traditional water heater when your appli...

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    $ 219.00 - $ 219.00
    $ 219.00
    $ 219.00 - $ 219.00
    $ 219.00

  • 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 - 105000250 - Sensei External Pump Harness

    Rinnai
    $ 15.00 - $ 15.00
    $ 15.00
    $ 15.00 - $ 15.00
    $ 15.00

    Rinnai Sensei Pump Harness External Recirculation Pump Wire Harness (Part Number 105000250) is the essential accessory you need when adding an exte...

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    $ 15.00 - $ 15.00
    $ 15.00
    $ 15.00 - $ 15.00
    $ 15.00
  • Eemax LavAdvantage tankless electric water heater product detail
    Eemax LavAdvantage tankless electric water heater front view

    Eemax LavAdvantage SPEX55T Tankless Electric Water Heater | 5.5kW 240V Thermostatic

    Eemax
    $ 0.00 - $ 0.00
    $ 0.00
    $ 308.43
    $ 308.43 - $ 308.43
    $ 308.43

    Eemax LavAdvantage SPEX55T Thermostatic Tankless Electric Water Heater Brand: Eemax SKU: SPEX55T Product Details The Eemax SPEX55T LavAdvanta...

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    $ 0.00 - $ 0.00
    $ 0.00
    $ 308.43
    $ 308.43 - $ 308.43
    $ 308.43
  • Rinnai - Rinnai Connect Cable MSB-M - - Water Heater Controllers - Big Frog Supply

    Rinnai - MSB-M - Connect Cable

    Rinnai
    $ 102.00 - $ 102.00
    $ 102.00
    $ 102.00 - $ 102.00
    $ 102.00

    Rinnai Connect Cable MSB-M for Rinnai tankless water heaters. 13.1 ft with terminal connectors.

    $ 102.00 - $ 102.00
    $ 102.00
    $ 102.00 - $ 102.00
    $ 102.00
  • 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

  • Rheem - RTG20006DW - Main Control

    Rheem
    $ 74.06 - $ 74.06
    $ 74.06
    $ 74.06 - $ 74.06
    $ 74.06

    The Rheem RTG20006DW is a remote control (UMC-117). HVAC replacement part Rheem RTG20006DW. Get your system working properly once again with replac...

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    $ 74.06 - $ 74.06
    $ 74.06
    $ 74.06 - $ 74.06
    $ 74.06

  • Stiebel Eltron - SHC4MINITANK - 234046 SHC 4 Mini-Tank Electric Water Heater, 4 Gallon, 1300W, 120V, 12-5/8" W x 19-3/4 12-1/2" D

    Stiebel Eltron
    $ 239.00 - $ 239.00
    $ 239.00
    $ 239.00 - $ 239.00
    $ 239.00

    Spec Sheet Install Manual Stiebel Eltron 23406 Details If you're storing 30+ gallons of hot water in a traditional water heater when your applic...

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    $ 239.00 - $ 239.00
    $ 239.00
    $ 239.00 - $ 239.00
    $ 239.00

  • 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
  • Eemax FlowCo tankless electric water heater with FlowCo branding
    Eemax FlowCo tankless electric water heater front view

    Eemax SPEX55 FlowCo Tankless Electric Water Heater | 5.5kW 240V Thermostatic

    Eemax
    $ 0.00 - $ 0.00
    $ 0.00
    $ 237.69
    $ 237.69 - $ 237.69
    $ 237.69

    Eemax SPEX55 FlowCo Thermostatic Tankless Electric Water Heater Brand: Eemax SKU: SPEX55 Product Details The Eemax SPEX55 FlowCo is a high-pe...

    View full details
    $ 0.00 - $ 0.00
    $ 0.00
    $ 237.69
    $ 237.69 - $ 237.69
    $ 237.69
  • Eemax LavAdvantage tankless electric water heater product detail
    Eemax LavAdvantage tankless electric water heater front view
    Sold out

    Eemax LavAdvantage SPEX55T-ML Multi-Lav Tankless Water Heater | 5.5kW 240V

    Eemax
    $ 0.00 - $ 0.00
    $ 0.00
    $ 281.99
    $ 281.99 - $ 281.99
    $ 281.99

    Eemax LavAdvantage SPEX55T-ML Multi-Lavatory Tankless Electric Water Heater Brand: Eemax SKU: SPEX55T-ML Product Details The Eemax SPEX55T-ML...

    View full details
    $ 0.00 - $ 0.00
    $ 0.00
    $ 281.99
    $ 281.99 - $ 281.99
    $ 281.99
    Sold out

  • Rinnai - MCC-601-W - Commercial Temp Controller - White

    Rinnai
    $ 178.34 - $ 178.34
    $ 178.34
    $ 178.34 - $ 178.34
    $ 178.34

    The MCC-601-W is made from premium materials, this Item offers great function and value for your home. This fixture is part of Rinnai's decorativ...

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    $ 178.34 - $ 178.34
    $ 178.34
    $ 178.34 - $ 178.34
    $ 178.34
  • 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...

    View full details
    $ 207.26 - $ 207.26
    $ 207.26
    $ 207.26 - $ 207.26
    $ 207.26
    Sold out
  • 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
  • Sold out

    Rheem - RTG-70DVLN-3 - Mid Efficiency 70 Direct Vent Indoor Natural Gas EcoNet Enabled Tankless Water Heater

    Rheem
    $ 804.00 - $ 804.00
    $ 804.00
    $ 804.00 - $ 804.00
    $ 804.00

    Spec Sheet Mid Efficiency 70 Direct Vent Indoor Natural Gas EcoNet Enabled Tankless Water Heater with 12 Year Limited Warranty   Rheem RTG is a s...

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    $ 804.00 - $ 804.00
    $ 804.00
    $ 804.00 - $ 804.00
    $ 804.00
    Sold out

  • Rheem - RTG-95DVLN-3 - Mid Efficiency 9.5 GPM Indoor Natural Gas EcoNet Included Tankless Water Heater

    Rheem
    $ 1,543.00 - $ 1,543.00
    $ 1,543.00
    $ 1,543.00 - $ 1,543.00
    $ 1,543.00

    Spec Sheet Mid Efficiency 9.5 GPM Indoor Natural Gas EcoNet Included Tankless Water Heater with 12 Year Limited Warranty Rheem RTG is a series of...

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    $ 1,543.00 - $ 1,543.00
    $ 1,543.00
    $ 1,543.00 - $ 1,543.00
    $ 1,543.00

  • 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 ...

    View full details
    $ 81.00 - $ 81.00
    $ 81.00
    $ 81.00 - $ 81.00
    $ 81.00

Quick choosing guide

  1. Size by flow: estimate peak demand in GPM at your winter inlet temperature rise. Whole-home gas units often cover 5–11+ GPM; electric point-of-use fits sinks and small loads.
  2. Pick fuel & placement: Gas for highest flow; choose indoor with proper venting or outdoor where climate allows. Electric units need the correct amperage and breakers.
  3. Efficiency: select condensing for higher efficiency and cooler exhaust; plan condensate drain where required.
  4. Faster hot water: choose a model with a built-in recirc pump or add a recirc kit and controller.
  5. Complete the install: vent kit and terminations for gas models; isolation/service valves; pipe covers; WiFi or wall controllers. Use NG/LP conversion kits only as specified.
  6. Maintenance: add a descaler/flush kit and schedule periodic cleaning to protect the heat exchanger.

Pro tips: Size for the coldest inlet temperature, verify gas line BTU capacity and vent route for NG/LP models, or breaker/wire size for electric units. Install isolation valves for easy flushing, set recirc schedules to cut wait time, and winterize outdoor units where required.

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