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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
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.
Customer Highlights
A summary of real customer reviews to highlight what shoppers are saying!Customer Highlights
A summary of real customer reviews to highlight what shoppers are saying!#2
NEW Rinnai RX199iN Condensing Smart Sense Natural Gas or Propane Tankless Water Heater, Indoor or Outdoor Water Heater, Up to 11.1 GPM, 199,000 BTU
The Rinnai RX199iN is a robust tankless water heater that is designed for both indoor and outdoor installation, offering flexibility in its setup. With a flow rate of up to 11.1 gallons per minute, it effectively supports multiple fixtures simultaneously, making it a great choice for larger households or those with high hot water demands. Its high energy efficiency rating of UEF .98 means you can expect notable savings on energy bills over time, which is especially beneficial for eco-conscious users.
Customer Highlights
A summary of real customer reviews to highlight what shoppers are saying!Customer Highlights
A summary of real customer reviews to highlight what shoppers are saying!#3
Stiebel Eltron Tankless Water Heater – Tempra 24 Plus – Electric, On Demand Hot Water, Eco, White, 20.2
The Stiebel Eltron Tempra 24 Plus is a solid choice for those in need of an electric tankless water heater suitable for whole-house applications. Its continuous flow technology ensures that you'll have an uninterrupted supply of hot water, which is a significant advantage for larger households or those with high hot water demands. The unit is compact and energy-efficient, featuring a design that doesn't require venting, which makes it a great option if space is limited. The energy savings monitor is a nice addition, allowing you to track your energy costs effectively.
Customer Highlights
A summary of real customer reviews to highlight what shoppers are saying!Customer Highlights
A summary of real customer reviews to highlight what shoppers are saying!Top 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
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
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 1338 this week
NEW Rinnai RX199iN Condensing Smart Sense Natural Gas or Propane Tankless Water Heater, Indoor or Outdoor Water Heater, Up to 11.1 GPM, 199,000 BTU
NEW Rinnai RX199iN Condensing Smart Sense Natural Gas or Propane Tankless Water Heater, Indoor or Outdoor Water Heater, Up to 11.1 GPM, 199,000 BTU
Flow Rate: 11.1 GPM
Energy Efficiency: UEF .98
Fuel Type: Natural gas or propane
Size and Installation: 18.5"W x 30.11"H, Wall mount
Temperature Rise: 140 Degrees Fahrenheit
Stiebel Eltron Tankless Water Heater – Tempra 24 Plus – Electric, On Demand Hot Water, Eco, White, 20.2
Stiebel Eltron Tankless Water Heater – Tempra 24 Plus – Electric, On Demand Hot Water, Eco, White, 20.2
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
Rheem 18kW 240V Tankless Electric Water Heater, Gray
Rheem 18kW 240V Tankless Electric Water Heater, Gray
Flow Rate: 4.4 GPM
Energy Efficiency: Advanced self-modulation tech
Fuel Type: Electric
Size and Installation: 14.5"W x 18.25"H, 3/4 inch NPT
Related Products
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
EcoSmart ECO 27 Tankless Water Heater, Electric, 27-kW - Quantity 1, 17 x 17 x 3.5
EcoSmart ECO 27 Tankless Water Heater, Electric, 27-kW - Quantity 1, 17 x 17 x 3.5
Flow Rate: 2.7 to 6.5 gallons/min
Energy Efficiency: 99% thermal efficiency
Fuel Type: Electric
Size and Installation: 17 x 17 x 3.75 inches, Wall Mount
Warranty and Support: Limited Lifetime Warranty
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
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
8.3 score
Rinnai RE180iP Non-Condensing Propane Tankless Water Heater, Up to 6.9 GPM, Indoor Installation, 180,000 BTU
Rinnai RE180iP Non-Condensing Propane Tankless Water Heater, Up to 6.9 GPM, Indoor Installation, 180,000 BTU
Flow Rate: 6.9 GPM
Energy Efficiency: High Efficiency
Fuel Type: Propane
Size and Installation: 14.05"W x 27.24"H, Indoor
Warranty and Support: 15 years heat exchanger, 5 years labor
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Buying Guide for the Best Tankless Water Heaters
Choosing the right tankless water heater can significantly improve your home's energy efficiency and ensure you have a reliable supply of hot water. Tankless water heaters, also known as on-demand water heaters, heat water directly without the use of a storage tank. When a hot water tap is turned on, cold water travels through a pipe into the unit and is heated either by a gas burner or an electric element. This means you get a constant supply of hot water. To find the best fit for your needs, consider the following key specifications and how they align with your household's requirements.Flow RateFlow rate, measured in gallons per minute (GPM), indicates how much hot water the unit can produce at a time. This is crucial because it determines whether the heater can meet your household's hot water demands. For example, a shower typically requires 2-3 GPM, while a dishwasher might need 1-2 GPM. If you have a large family or multiple hot water needs simultaneously, you'll need a higher flow rate. Conversely, for smaller households or less simultaneous usage, a lower flow rate will suffice. Assess your peak hot water usage to determine the appropriate flow rate for your home.
Energy EfficiencyEnergy efficiency is measured by the unit's Energy Factor (EF), which indicates how efficiently the water heater converts energy into hot water. A higher EF means better efficiency and lower energy costs. Tankless water heaters generally have higher EF ratings compared to traditional tank heaters. Look for units with an EF of 0.8 or higher for optimal efficiency. If reducing energy consumption and saving on utility bills is a priority for you, choose a model with a high EF rating.
Fuel TypeTankless water heaters can be powered by electricity, natural gas, or propane. The choice of fuel type affects installation costs, operating costs, and efficiency. Electric models are typically easier to install and maintain but may have higher operating costs depending on your local electricity rates. Gas models, while often more efficient and cheaper to operate, require proper venting and may have higher installation costs. Consider the availability and cost of fuel in your area, as well as your home's existing infrastructure, when choosing the fuel type.
Size and InstallationThe physical size of the tankless water heater and its installation requirements are important factors. Tankless units are generally more compact than traditional tank heaters, but you still need to ensure you have enough space for installation. Additionally, gas models require venting, which can add to the installation complexity. Electric models are usually easier to install but may require an upgrade to your electrical system. Evaluate the available space and the complexity of installation in your home to choose a unit that fits well and can be installed without significant modifications.
Temperature RiseTemperature rise refers to the difference between the incoming water temperature and the desired output temperature. This is important because it affects the heater's ability to provide hot water at the desired temperature. For instance, if your incoming water temperature is 50°F and you want it heated to 120°F, the unit needs to handle a 70°F temperature rise. Higher temperature rise requirements may reduce the flow rate. Consider the climate in your area and the typical temperature of your incoming water to ensure the unit can meet your hot water needs.
Warranty and SupportA good warranty and reliable customer support are essential for peace of mind and long-term satisfaction with your tankless water heater. Warranties can vary significantly between manufacturers, covering different components for different lengths of time. Look for a unit with a comprehensive warranty that covers both parts and labor for an extended period. Additionally, consider the reputation of the manufacturer and the availability of customer support. A strong warranty and good support can save you money and hassle in the long run.