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10 Best Tankless Gas Water Heaters 2025 in the United States
#1
Winner
Ranein Natural Gas Tankless Water Heater, Outdoor Max 7.4 GPM, 190,000 BTU Instant Hot Water Heater
The Ranein Natural Gas Tankless Water Heater offers a substantial flow rate of 7.4 GPM, making it suitable for households with multiple hot water outlets (4-6 points). Its high heating capacity of 190,000 BTU ensures quick and efficient heating, providing users with instant hot water without preheating delays.
Rating
9.9
Chosen by1,431
Flow Rate (GPM)
Energy Efficiency (EF Rating)
Size and Installation Space
Most important from
538 reviews
#2
Ranein Natural Gas Tankless Water Heater, Outdoor Max 5.3 GPM, 130,000 BTU Instant Hot Water Heater
The Ranein Natural Gas Tankless Water Heater is a strong contender in the market for those seeking an outdoor tankless gas water heater. It offers a maximum flow rate of 5.3 GPM, which is suitable for a household with 3-5 outlet points, ensuring you can run multiple showers or appliances simultaneously without running out of hot water. The 130,000 BTU rating ensures a high heating capacity, making it effective for quick and efficient water heating.
Rating
9.8
Flow Rate (GPM)
Energy Efficiency (EF Rating)
Size and Installation Space
Most important from
538 reviews
#3
Ranein Natural Gas Tankless Water Heater, Indoor Max 5.3 GPM, 130,000 BTU Instant Hot Water Heater
The Ranein Natural Gas Tankless Water Heater offers a maximum flow rate of 5.3 gallons per minute (GPM), which is suitable for serving 3-5 outlets simultaneously. This makes it a good option for a household with moderate hot water needs. With a BTU rating of 130,000, it provides ample heating capacity to deliver hot water on demand without the need for preheating, which is a significant convenience over traditional water heaters.
Rating
9.7
Flow Rate (GPM)
Energy Efficiency (EF Rating)
Venting Requirements
Most important from
538 reviews
Top 10 Best Tankless Gas Water Heaters 2025 in the United States
#1
Winner
9.9 score
Ranein Natural Gas Tankless Water Heater, Outdoor Max 7.4 GPM, 190,000 BTU Instant Hot Water Heater
Ranein Natural Gas Tankless Water Heater, Outdoor Max 7.4 GPM, 190,000 BTU Instant Hot Water Heater
Flow Rate (GPM): 7.4
BTU Rating: 190,000
Venting Requirements: specific venting for natural gas
Size and Installation Space: 24.3"H x 15"W x 8.3"D
Chosen by 1431 this week
Ranein Natural Gas Tankless Water Heater, Outdoor Max 5.3 GPM, 130,000 BTU Instant Hot Water Heater
Ranein Natural Gas Tankless Water Heater, Outdoor Max 5.3 GPM, 130,000 BTU Instant Hot Water Heater
Flow Rate (GPM): 5.3
BTU Rating: 130,000
Size and Installation Space: 14.2"W x 23.2"H
Ranein Natural Gas Tankless Water Heater, Indoor Max 5.3 GPM, 130,000 BTU Instant Hot Water Heater
Ranein Natural Gas Tankless Water Heater, Indoor Max 5.3 GPM, 130,000 BTU Instant Hot Water Heater
Flow Rate (GPM): 5.3
BTU Rating: 130,000
Size and Installation Space: 23.15 x 14.17 inches
Ranein Natural Gas Tankless Water Heater, Indoor Max 3.6 GPM, 80,000 BTU Instant Hot Water Heater
Ranein Natural Gas Tankless Water Heater, Indoor Max 3.6 GPM, 80,000 BTU Instant Hot Water Heater
Flow Rate (GPM): 3.6
BTU Rating: 80,000
Venting Requirements: exhaust pipe included
Size and Installation Space: 19.09"W x 7.67"H
Ranein Propane Gas Tankless Water Heater with Vent Pipe, Indoor Max 4.3 GPM, 100,000 BTU Instant Hot Water Heater
Ranein Propane Gas Tankless Water Heater with Vent Pipe, Indoor Max 4.3 GPM, 100,000 BTU Instant Hot Water Heater
Flow Rate (GPM): 4.3
BTU Rating: 100,000
Venting Requirements: exhaust pipe included
Size and Installation Space: 18.89"W x 8.85"H x 13"D
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Ranein Natural Gas Tankless Water Heater with Vent Pipe, Indoor Max 4.3 GPM, 100,000 BTU Instant Hot Water Heater
Ranein Natural Gas Tankless Water Heater with Vent Pipe, Indoor Max 4.3 GPM, 100,000 BTU Instant Hot Water Heater
Flow Rate (GPM): 4.3
BTU Rating: 100,000
Venting Requirements: Included vent pipe
Size and Installation Space: 18.89"W x 8.85"H, Wall mount
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 (GPM): 9.5
Energy Efficiency (EF Rating): 0.93
BTU Rating: 199,900
Size and Installation Space: 17.7"W x 23.7"H
Temperature Rise: 100 to 140°F
Rheem RTG-70DVLP-3 High Efficiency Non-Condensing Indoor Tankless Liquid Propane Water Heater, 7.0 GPM
Rheem RTG-70DVLP-3 High Efficiency Non-Condensing Indoor Tankless Liquid Propane Water Heater, 7.0 GPM
Flow Rate (GPM): 7 GPM
Energy Efficiency (EF Rating): 0.82
Venting Requirements: Indoor setup
Size and Installation Space: 13.5" x 24.2"
#10
8.2 score
Rheem RTG-70XLN-3 High Efficiency Non-Condensing Outdoor Tankless Natural Gas Water Heater, 7.0 GPM, Gray
Rheem RTG-70XLN-3 High Efficiency Non-Condensing Outdoor Tankless Natural Gas Water Heater, 7.0 GPM, Gray
Flow Rate (GPM): 7
Venting Requirements: Outdoor use requires proper venting
Size and Installation Space: 19% smaller, 22% lighter than before
Temperature Rise: Max temperature 140°F
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Buying Guide for the Best Tankless Gas Water Heaters
Choosing the right tankless gas water heater can significantly improve your home's energy efficiency and ensure you have a reliable supply of hot water. Tankless water heaters heat water on demand, which means they don't store hot water like traditional tank heaters. This can save you money on energy bills and provide an endless supply of hot water. However, selecting the right model involves understanding several key specifications to ensure it meets your household's needs.Flow Rate (GPM)Flow rate, measured in gallons per minute (GPM), indicates how much hot water the unit can produce at a given time. This is crucial because it determines whether the heater can meet your household's hot water demands. For example, a flow rate of 3-4 GPM is suitable for small households with one or two fixtures running simultaneously, while larger households with multiple fixtures may require a flow rate of 7-10 GPM. To choose the right flow rate, consider the number of people in your home and the number of hot water fixtures you expect to use at the same time.
Energy Efficiency (EF Rating)The Energy Factor (EF) rating measures the efficiency of the water heater in converting fuel into hot water. A higher EF rating means the unit is more efficient, which can lead to lower energy bills. EF ratings typically range from 0.8 to 0.99. For those looking to maximize energy savings, a higher EF rating is preferable. However, even a mid-range EF rating can offer significant improvements over traditional tank water heaters. Consider your energy consumption habits and prioritize higher EF ratings if reducing energy costs is a primary concern.
BTU RatingBTU (British Thermal Unit) rating measures the heating capacity of the water heater. Higher BTU ratings mean the unit can heat water more quickly and handle higher flow rates. BTU ratings for tankless gas water heaters typically range from 120,000 to 199,000 BTUs. If you have a large household or high hot water demand, a higher BTU rating will ensure you have enough hot water. For smaller households or lower hot water usage, a lower BTU rating may be sufficient and more cost-effective.
Venting RequirementsTankless gas water heaters require proper venting to expel combustion gases safely. There are two main types of venting: direct vent and power vent. Direct vent systems draw air from outside and are ideal for homes with limited indoor ventilation, while power vent systems use indoor air and require an exhaust fan. The choice between these depends on your home's layout and existing ventilation infrastructure. Ensure you understand your home's venting capabilities and choose a model that aligns with them to ensure safe and efficient operation.
Size and Installation SpaceTankless gas water heaters are generally more compact than traditional tank heaters, but they still require adequate space for installation and maintenance. Consider the dimensions of the unit and the available space in your home. Ensure there is enough clearance around the unit for proper ventilation and access for maintenance. If space is limited, look for more compact models designed for tight installations. Proper sizing and placement are crucial for both performance and safety.
Temperature RiseTemperature rise refers to the difference between the incoming cold water temperature and the desired hot water temperature. This is important because it affects the heater's ability to provide consistent hot water. For example, if your incoming water temperature is 50°F and you want it heated to 120°F, the required temperature rise is 70°F. Different models have varying capabilities for temperature rise, so choose one that can handle the temperature rise needed for your region and usage patterns. Consider the climate you live in and the typical temperature of your incoming water when making your selection.