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10 Best Tankless Water Heaters 2025 in the United States

#1

Winner

10.0 score

NEW Rinnai RXP199iN Condensing Smart Sense Natural Gas or Propane Tankless Water Heater, Indoor or Outdoor Water Heater, Up to 11.1 GPM, 199,000 BTU, with Recirculation Pump

NEW Rinnai RXP199iN Condensing Smart Sense Natural Gas or Propane Tankless Water Heater, Indoor or Outdoor Water Heater, Up to 11.1 GPM, 199,000 BTU, with Recirculation Pump

Rinnai

10.0 score

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The Rinnai RXP199iN Condensing Smart Sense Tankless Water Heater offers impressive versatility, operating with either natural gas or propane and being suitable for both indoor and outdoor installations. With a flow rate of up to 11.1 GPM, it can handle multiple fixtures at once, making it ideal for larger households. Its compact size and modern design, which includes features like Quick Flush and Smart-Circ Intelligent Recirculation, enhance its efficiency and user-friendliness.

Rating
10.0
Chosen by1,228
Flow Rate
Energy Efficiency
Fuel Type

Most important from
281 reviews

Flow Rate
Powerful enough to provide hot water simultaneously at four places in a household of five or more.
Energy Efficiency
For maximum energy efficiency, the BLE Bluetooth button accessory is recommended to activate the water recirculation cycle, saving lots of water and energy.
Fuel Type
Supports both natural gas and propane, making it versatile for different household setups.
Size and Installation
Installation is straightforward with the excellent, detailed instruction manual, though pre-planning for mounting location, materials, and electrical service is advised.
Warranty and Support
While the quick start guide can be confusing, the manufacturer's tech support is very helpful for resolving issues.
#2
9.7 score

Stiebel Eltron Tankless Water Heater – Tempra 36 Plus – Electric, On Demand Hot Water, Eco, White

9%OFF

Stiebel Eltron Tankless Water Heater – Tempra 36 Plus – Electric, On Demand Hot Water, Eco, White

Stiebel Eltron

9.7 score

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The Stiebel Eltron Tempra 36 Plus is a high-powered electric tankless water heater designed to provide continuous hot water on demand. Its 36 kW wattage supports a maximum flow rate of about 1.5 gallons per minute, which is ideal for point-of-use or smaller household setups but may struggle to supply multiple outlets simultaneously in larger homes. This model features advanced flow control and self-modulation technology that adjusts energy use to match the demand, making it energy-efficient and helping to reduce utility bills. The digital LED display allows for precise temperature adjustments, which is a convenient feature for users wanting consistent water temperature.

Rating
9.7
Flow Rate (Gallons Per Minute - GPM)
Energy Source (Gas vs. Electric)
Temperature Rise

Most important from
2179 reviews

Flow Rate (Gallons Per Minute - GPM)
Provides unlimited hot water with the ability for simultaneous showers, only limited when combined with heavy appliance use.
Energy Source (Gas vs. Electric)
Uses no power when not in use, delivering instant hot water even after long periods of inactivity.
Temperature Rise
Accurate and easy temperature control with presets that simplify filling tasks like soaking tubs perfectly.
Installation Requirements
Compact, wall-mounted design allows installation close to points of use, drastically reducing wait time for hot water.
Size and Dimensions
Quiet operation and space-saving footprint make it ideal for homes where noise and space are concerns.
Maintenance Needs
A whole-house water filtration system is recommended to prevent mineral buildup and maintain performance.
#3
7.3 score

Rinnai CX199iN Condensing Smart Sense Commercial Natural Gas or Propane Tankless Water Heater, 199,000 BTU, 11.1 GPM

Rinnai CX199iN Condensing Smart Sense Commercial Natural Gas or Propane Tankless Water Heater, 199,000 BTU, 11.1 GPM

Rinnai

7.3 score

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The Rinnai CX199iN High Efficiency Plus Natural Gas Interior Tankless Water Heater is designed for those looking for a high-performance water heating solution. With a maximum flow rate of 11.1 gallons per minute (GPM), it can handle multiple hot water demands simultaneously, making it suitable for larger households. The 96% energy efficiency rating is impressive, indicating that it can significantly reduce energy costs compared to traditional water heaters.

Top 10 Best Tankless Water Heaters 2025 in the United States

#1

Winner

10.0  score
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Rinnai

NEW Rinnai RXP199iN Condensing Smart Sense Natural Gas or Propane Tankless Water Heater, Indoor or Outdoor Water Heater, Up to 11.1 GPM, 199,000 BTU, with Recirculation Pump

Flow Rate: 11.1 GPM
Energy Efficiency: 0.98
Fuel Type: Natural gas or propane
Size and Installation: 19"W x 31"H, Wall mount

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Chosen by 1228 this week

#2
9.7  score
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Stiebel Eltron

Stiebel Eltron Tankless Water Heater – Tempra 36 Plus – Electric, On Demand Hot Water, Eco, White

Flow Rate (Gallons Per Minute - GPM): 1.5 Gallons Per Minute
Energy Source (Gas vs. Electric): Electric
Installation Requirements: Wall mount; pro installation recommended
Size and Dimensions: 16.63"W x 14.5"H
Maintenance Needs: Periodic descaling in hard water

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9% OFF
#3
7.3  score
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Rinnai

Rinnai CX199iN Condensing Smart Sense Commercial Natural Gas or Propane Tankless Water Heater, 199,000 BTU, 11.1 GPM

Flow Rate: 11.1 GPM
Energy Efficiency: 96%
Fuel Type: Natural Gas or Propane
Size and Installation: 18.5"W x 30.11"H, Wall Mount

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#4
7.3  score
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FOGATTI

FOGATTI Natural Gas Tankless Water Heater Indoor - Max 7.5 GPM 170,000 BTU, CSA Certified Compact Design On Demand Instant Hot Water Heater - Instagas Comfort 170S Series

Flow Rate (Gallons Per Minute - GPM): 7.5 Gallons Per Minute
Energy Source (Gas vs. Electric): Natural Gas
Installation Requirements: Indoor, pro install, proper ventilation
Size and Dimensions: 17.1"W x 26.2"H
Maintenance Needs: Drain heater below 5°F to prevent damage

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20% OFF
#5
7.3  score
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Rheem

Rheem RTGH-95DVELN-3 Super High Efficiency Condensing Indoor Tankless Natural Gas Water Heater, 9.5 GPM with WiFi

Flow Rate: 9.5 Gallons Per Minute
Energy Efficiency: 0.93
Fuel Type: Natural Gas
Size and Installation: 17.7"W x 23.7"H, 51.3 pounds
Temperature Rise: 140 Degrees Fahrenheit

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#6
7.3  score
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Rheem

Rheem RTGH-95DVLN-3 RTGH Series 9.5 GPM 199,900 BTU 120 Volt Residential Indoor Natural Gas Tankless Water Heater Stainless Steel

Flow Rate: 9.5 GPM
Energy Efficiency: 0.93
Fuel Type: Natural Gas
Size and Installation: 17.7"W x 23.7"H, Wall-mounted
Temperature Rise: 100 to 140°F
Warranty and Support: 1-year labor, 5-year parts

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#7
7.3  score
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Stiebel Eltron

Stiebel Eltron Tankless Water Heater – Tempra 24 Plus – Electric, On Demand Hot Water, Eco, White

Flow Rate: continuous flow
Energy Efficiency: energy-efficient
Fuel Type: Electric
Size and Installation: 16.63"W x 14.5"H, Wall Mount
Warranty and Support: 7-Year Leakage, 3-Year Parts

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#8
7.3  score
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Rinnai

Rinnai RE199iN Non-Condensing Natural Gas Tankless Water Heater, Up to 9.8 GPM, Indoor Installation, 199,000 BTU

Flow Rate: 7.6 GPM
Energy Efficiency: better energy efficiency
Fuel Type: Natural Gas
Size and Installation: 14.05"W x 27.28"H, compact
Warranty and Support: 15 years heat exchanger

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#9
7.0  score
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Rheem

Rheem RTG-95DVLN-3 High Efficiency Non-Condensing Indoor Tankless Natural Gas Water Heater, 9.5 GPM

Flow Rate: 9.5 gallons per minute
Energy Efficiency: 0.82
Fuel Type: Natural Gas
Size and Installation: 13.5" x 24", wall-mounted, indoor
Temperature Rise: Max 140°F

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#10
7.0  score
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Rheem

Rheem RRTGH84DVLN3701171 Rheem RTGH Series 8.4 GPM 157,000 BTU 120 Volt Residential Indoor Natural Gas Tankless Water Heater Stainless Steel

Flow Rate: 8.4 GPM
Energy Efficiency: 0.93
Fuel Type: Natural Gas
Size and Installation: 17.7"W x 23.7"H, Wall Mount
Temperature Rise: 100 to 140°F
Warranty and Support: 1 year labor, 15 years heat exchanger

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Buying Guide for the Best Tankless Water Heaters

Choosing a tankless water heater can be a smart way to ensure you have hot water on demand without taking up much space or worrying about running out. Unlike traditional heaters with storage tanks, tankless models heat water only when it's needed, making them energy-efficient and generally more durable over time. To find the best fit for your household, it's essential to understand the main specifications and features, as these will directly affect your experience and satisfaction.
Flow Rate (Gallons Per Minute - GPM)Flow rate measures how much hot water the unit can provide at once, typically shown in gallons per minute (GPM). This is important because if the flow rate is too low, you might struggle to use hot water in multiple places at the same time (like a shower and kitchen sink). Lower GPM units (around 2-4 GPM) work well for small households or single fixtures, while larger homes or those who need hot water at several points at once should look at higher GPM units (6+ GPM). To pick the right flow rate, add up the GPM of appliances you normally use together at peak times; choose a model that covers your total need.
Temperature RiseTemperature rise tells you how much a heater can increase the water's temperature as it flows through. This matters because the incoming water is colder in some places or during certain seasons. Units are rated based on how much they can heat the water at a given flow rate. If you live in a colder area, or want extra-hot showers, choose a model that can deliver a higher temperature rise at your required flow rate. Manufacturers often provide charts; match your expected flow and local cold water temperature to select the right fit.
Energy Source (Gas vs. Electric)Tankless water heaters can be powered by natural gas, propane, or electricity. Gas models usually provide higher flow rates and can keep up with larger demand, while electric models are often more compact and easier to install in smaller spaces. The choice comes down to what's available in your home and your hot water use. If you need high capacity or already have a gas line, gas may be better. For smaller needs, or if you want a simpler setup, electric could be the way to go.
Installation RequirementsInstallation involves factors like ventilation for gas models, electrical capacity for electric ones, and space for fitting the unit on a wall. Gas models need proper venting to the outside, which can add to the installation steps, while electric heaters often require an upgraded electrical panel. Consider what's easier and feasible in your home; if your installation location can't easily be adapted, that should guide your choice.
Size and DimensionsWhile tankless heaters are much smaller than traditional tanks, they still come in different sizes. Size affects where you can place your unit, especially if you want to install it in a tight spot, like under a sink or in a closet. Measure your available space and make sure the unit you pick will fit comfortably, including space for any necessary maintenance.
Maintenance NeedsTankless units generally need less day-to-day attention than tanks, but they should still be cleaned (descaled) annually, especially if you have hard water. Some models make this easier than others. If you want minimal hassle, look for units with simple maintenance requirements and easy access for servicing. Think about your ability and willingness to keep up with maintenance when making your choice.

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