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10 Best Tankless Water Heaters 2025 in the United States

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Our technology thoroughly searches through the online shopping world, reviewing hundreds of sites. We then process and analyze this information, updating in real-time to bring you the latest top-rated products. This way, you always get the best and most current options available.

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Our Top Picks

#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

Rating
9.8
Chosen by1,294
Flow Rate
Energy Efficiency
Fuel Type

Most important from
139 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.

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.

Additionally, the unit boasts a high energy efficiency factor of 0.98, translating to significant energy savings. The option for WiFi connectivity through the Control-R module adds to its smart appeal, although this module is not included with the water heater. Installation should be performed by a professional, which adds to the initial cost but ensures proper setup and operation. The unit's temperature rise and maximum output of 199,000 BTU make it suitable for demanding environments, but users should ensure their home’s infrastructure supports this capacity.

The warranty and support are implied to be robust through Rinnai's recommendation for professional installation and their central app for service and troubleshooting. This tankless water heater is best suited for those needing a high-performance, energy-efficient solution for a large household.

Rating
9.8
Chosen by1,294
Flow Rate
Energy Efficiency
Fuel Type

Most important from
139 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

Stiebel Eltron Tankless Water Heater – Tempra 24 Plus – Electric, On Demand Hot Water, Eco, White, 20.2

Rating
9.6
Flow Rate
Energy Efficiency
Size and Installation

Most important from
2052 reviews

Flow Rate
What truly sets this heater apart is its ability to provide a continuous flow of hot water, even with multiple outlets in use.
Energy Efficiency
This tankless water heater's performance has exceeded my expectations in terms of convenience and efficiency.
Size and Installation
The unit is impressively quiet, and its space-saving design is a game-changer.
Temperature Rise
The temperature control is precise, ensuring you get the hot water you desire without any fuss.

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.

One of the key strengths of the Tempra 24 Plus is its advanced flow control, which helps maintain consistent water temperatures even when multiple outlets are in use. This is particularly beneficial during peak usage times. The digital temperature display and preset memory buttons make it user-friendly, even for individuals who might not be tech-savvy.

However, there are a few drawbacks to consider. The unit requires a minimum electric service of 150 A, which may be a limitation for homes with older electrical systems. Installation might be tricky for DIY enthusiasts, as it typically requires a professional to handle the electric setup. Additionally, while the unit operates quietly, some users might find that the slight reduction in flow during high demand could be a minor inconvenience. The warranty provided, including a 7-Year Leakage and 3-Year Parts Warranty, adds a layer of confidence in its reliability. The Stiebel Eltron Tempra 24 Plus is a well-rounded option for those prioritizing efficiency and continuous hot water, though it's best suited for households ready for potential electrical upgrades.

Rating
9.6
Flow Rate
Energy Efficiency
Size and Installation

Most important from
2052 reviews

Flow Rate
What truly sets this heater apart is its ability to provide a continuous flow of hot water, even with multiple outlets in use.
Energy Efficiency
This tankless water heater's performance has exceeded my expectations in terms of convenience and efficiency.
Size and Installation
The unit is impressively quiet, and its space-saving design is a game-changer.
Temperature Rise
The temperature control is precise, ensuring you get the hot water you desire without any fuss.
#3

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

Rating
9.4
Flow Rate
Size and Installation
Temperature Rise

Most important from
90 reviews

Flow Rate
Kitchen is 50+ feet away, and the water heats up faster than the tank heater it replaced.
Size and Installation
The unit is larger than some, but not as heavy as most. The installation was fairly straightforward.
Temperature Rise
Once all the plumbing was complete, we plugged it in and only had to adjust the temperature up 5 degrees. It's running great and has had no issues.

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.

One standout feature is the integrated digital display, making it easy to monitor and adjust temperature settings, which range from 100 to 140 degrees Fahrenheit. This adaptability allows users to find a comfortable temperature that suits their needs. Additionally, the natural gas fuel type is generally more efficient than electric options, further enhancing its appeal.

On the downside, installation can be a bit tricky if you're not familiar with gas appliances. It requires a wall-mounted setup and adequate venting, which might necessitate professional installation, adding to the cost. The warranty coverage, while decent with a 1-year labor and 5-year parts warranty, might be considered lacking compared to competitors that offer longer terms.

Another point to consider is that the heater's weight (about 59.9 pounds) and size (17.7”W x 23.7”H) may pose challenges during installation, especially in tighter spaces. It’s essential to ensure that your home can accommodate this unit before purchasing.

The Rheem RTGH-95DVLN-3 is a robust option for families seeking efficient hot water solutions. Its high flow rate and energy efficiency make it a strong contender in the tankless water heater market, but potential buyers should weigh the installation requirements and warranty duration against their specific needs.

Rating
9.4
Flow Rate
Size and Installation
Temperature Rise

Most important from
90 reviews

Flow Rate
Kitchen is 50+ feet away, and the water heats up faster than the tank heater it replaced.
Size and Installation
The unit is larger than some, but not as heavy as most. The installation was fairly straightforward.
Temperature Rise
Once all the plumbing was complete, we plugged it in and only had to adjust the temperature up 5 degrees. It's running great and has had no issues.

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.

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