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10 Best Tankless Water Heaters 2025 in the United States
#1
Winner
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
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 by1,483
Flow Rate
Energy Efficiency
Fuel Type
Most important from
279 reviews
#2
Stiebel Eltron Tankless Water Heater – Tempra 36 Plus – Electric, On Demand Hot Water, Eco, White
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
2177 reviews
#3
Rheem RTGH-95DVLN-3 RTGH Series 9.5 GPM 199,900 BTU 120 Volt Residential Indoor Natural Gas Tankless Water Heater Stainless Steel
The Rheem RTGH-95DVLN-3 is a solid choice for those in need of a tankless water heater, especially for residential use. With a flow rate of up to 9.5 gallons per minute, it can easily meet the hot water demands of larger households or simultaneous usage across multiple fixtures. Its energy efficiency rating of 0.93 ensures that it operates economically, which can translate to lower energy bills over time.
Rating
8.2
Flow Rate
Size and Installation
Temperature Rise
Most important from
148 reviews
Top 10 Best Tankless Water Heaters 2025 in the United States
#1
Winner
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
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
Chosen by 1483 this week
Stiebel Eltron Tankless Water Heater – Tempra 36 Plus – Electric, On Demand Hot Water, Eco, White
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
Rheem RTGH-95DVLN-3 RTGH Series 9.5 GPM 199,900 BTU 120 Volt Residential Indoor Natural Gas Tankless Water Heater Stainless Steel
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
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
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
Stiebel Eltron Tankless Water Heater – Tempra 24 Plus – Electric, On Demand Hot Water, Eco, White
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
Related Products
Rinnai RE199iN Non-Condensing Natural Gas Tankless Water Heater, Up to 9.8 GPM, Indoor Installation, 199,000 BTU
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
Rheem RRTGH84DVLN3701171 Rheem RTGH Series 8.4 GPM 157,000 BTU 120 Volt Residential Indoor Natural Gas Tankless Water Heater Stainless Steel
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
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
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
Rheem RTEX-24 24kW 240V Electric Tankless Water Heater, Gray
Rheem RTEX-24 24kW 240V Electric Tankless Water Heater, Gray
Flow Rate: 5.9 GPM
Energy Efficiency: 99.8%
Fuel Type: Electric
Size and Installation: 17.63"W x 18.25"H x 3.5"D
#10
FOGATTI Natural Gas Tankless Water Heater Outdoor - Max 8.1 GPM 180,000 BTU, CSA Certified Compact Design On Demand Instant Hot Water Heater - Instagas Comfort 180S Series
FOGATTI Natural Gas Tankless Water Heater Outdoor - Max 8.1 GPM 180,000 BTU, CSA Certified Compact Design On Demand Instant Hot Water Heater - Instagas Comfort 180S Series
Flow Rate: 8.1 Gallons Per Minute
Energy Efficiency: >0.81
Fuel Type: Natural Gas
Size and Installation: 17.1"W x 26.2"H, Wall-Mounted
Warranty and Support: 2-year unit, 5-year 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.