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10 Best Outdoor 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 is a highly efficient tankless water heater that can operate on either propane or natural gas, making it versatile in terms of energy source. With a flow rate of up to 11.1 gallons per minute (GPM), it can supply hot water for multiple fixtures simultaneously, which is great for larger households or outdoor uses where instant hot water is a necessity. Its BTU rating of 199,000 indicates strong heating performance.
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 Condensing Smart Sense Tankless Water Heater is a solid choice for those seeking an efficient and high-capacity hot water solution for their home. With a flow rate of up to 11.1 gallons per minute (GPM), this heater can handle multiple fixtures simultaneously, making it ideal for larger households or homes with high hot water demand. Its 199,000 BTU rating ensures that it heats water quickly, maintaining a steady supply.
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
Rinnai RE199eN Non-Condensing Natural Gas Tankless Water Heater, Up to 9.8 GPM, Outdoor Installation, 199,000 BTU
The Rinnai RE199eN is a non-condensing natural gas tankless water heater designed for outdoor installation, capable of delivering up to 7.6 GPM, making it suitable for homes with multiple fixtures running simultaneously. Its compact size, comparable to a small suitcase, allows for a space-saving installation. With a powerful 199,000 BTU rating, it ensures a significant temperature rise and reliable hot water supply.
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 Outdoor 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 (GPM): 11.1
Energy Efficiency: UEF .98
BTU Rating: 199000
Installation and Venting: Professional, outdoor with proper venting
Durability and Weather Resistance: Durable, suitable for various environments
Chosen by 1289 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 (GPM): 11.1
Energy Efficiency: .98 UEF
BTU Rating: 199000
Installation and Venting: Versa Vent, professional install
Warranty and Support: robust warranty and support
Rinnai RE199eN Non-Condensing Natural Gas Tankless Water Heater, Up to 9.8 GPM, Outdoor Installation, 199,000 BTU
Rinnai RE199eN Non-Condensing Natural Gas Tankless Water Heater, Up to 9.8 GPM, Outdoor Installation, 199,000 BTU
Flow Rate (GPM): 7.6
Energy Efficiency: heats water only when necessary
BTU Rating: 199,000
Temperature Rise: significant rise
Installation and Venting: outdoor, professional installation recommended
Durability and Weather Resistance: withstand outdoor conditions
Warranty and Support: heat exchanger 15 years, labor 5 years
Rheem RTGH-95DVELN-3 Super High Efficiency Condensing Indoor Tankless Natural Gas Water Heater, 9.5 GPM with WiFi
Rheem RTGH-95DVELN-3 Super High Efficiency Condensing Indoor Tankless Natural Gas Water Heater, 9.5 GPM with WiFi
Flow Rate (GPM): 9.5
Energy Efficiency: high energy efficiency
Installation and Venting: professional assistance required
Durability and Weather Resistance: durable and weather resistant
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
Energy Efficiency: Oxygen-free copper tank minimizes heat loss
BTU Rating: 100,000
Temperature Rise: Adjusts temperature based on seasonal changes
Installation and Venting: Easy install with standard fittings
Related Products
Rheem RTGH-95DVELP-3 Super High Efficiency Condensing Indoor Tankless Liquid Propane Water Heater, 9.5 GPM with WiFi
Rheem RTGH-95DVELP-3 Super High Efficiency Condensing Indoor Tankless Liquid Propane Water Heater, 9.5 GPM with WiFi
Flow Rate (GPM): 9.5
Energy Efficiency: Super High Efficiency
Installation and Venting: Indoor unit, needs proper venting
Durability and Weather Resistance: Needs weather protection
FOGATTI Natural Gas Tankless Water Heater - Outdoor Installation Up to 8.1 GPM, Gray Instant Hot Water Heater - Instagas Comfort 180S Series
FOGATTI Natural Gas Tankless Water Heater - Outdoor Installation Up to 8.1 GPM, Gray Instant Hot Water Heater - Instagas Comfort 180S Series
Flow Rate (GPM): 8.1
Energy Efficiency: >0.81
BTU Rating: 180,000
Installation and Venting: Wall-Mounted, Outdoor
Durability and Weather Resistance: DC fan for harsh weather
Warranty and Support: 2 years unit, 5 years exchanger
Rheem IKONIC RECTGH-SR11iN Super High Efficiency Condensing Tankless Natural Gas Water Heater with Recirculation, 11.2 GPM
Rheem IKONIC RECTGH-SR11iN Super High Efficiency Condensing Tankless Natural Gas Water Heater with Recirculation, 11.2 GPM
Flow Rate (GPM): 11.2
Energy Efficiency: Energy Star
Installation and Venting: Wall, Outdoor kit
Warranty and Support: Rheem's warranty and support
#10
7.9 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): 7.0
Energy Efficiency: high
Temperature Rise: 140°F
Installation and Venting: Outdoor, Wall-mounted
Durability and Weather Resistance: freeze protection
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Buying Guide for the Best Outdoor Tankless Water Heaters
Choosing the right outdoor tankless water heater can significantly enhance your comfort and convenience, especially if you live in an area where hot water is essential. Tankless water heaters provide hot water on demand, which means you don't have to wait for a tank to fill up and heat. This can save energy and reduce your utility bills. When selecting an outdoor tankless water heater, it's important to consider several key specifications to ensure you get the best fit for your needs.Flow Rate (GPM)Flow rate, measured in gallons per minute (GPM), indicates how much hot water the heater 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 or single applications like a shower, while 7-10 GPM is better for larger households with multiple simultaneous hot water needs. Assess your household's hot water usage to choose the right flow rate.
Energy EfficiencyEnergy efficiency is measured by the unit's Energy Factor (EF) or Uniform Energy Factor (UEF). This spec indicates how efficiently the heater converts energy into hot water. Higher EF or UEF values mean better efficiency and lower operating costs. Look for models with high efficiency ratings if you want to save on energy bills and reduce your environmental footprint. Consider your usage patterns and prioritize efficiency if you use hot water frequently.
BTU RatingBTU (British Thermal Unit) rating measures the heater's heating capacity. Higher BTU ratings mean the heater can produce more hot water quickly. For larger households or colder climates, a higher BTU rating (e.g., 150,000-200,000 BTUs) is recommended to ensure a steady supply of hot water. For smaller households or warmer climates, a lower BTU rating (e.g., 100,000-150,000 BTUs) may be sufficient. Match the BTU rating to your hot water needs and climate conditions.
Temperature RiseTemperature rise refers to the increase in water temperature that the heater can achieve. This is important because it affects how hot the water will be when it reaches your tap. If you live in a colder area where the incoming water temperature is low, you'll need a heater with a higher temperature rise capability. Typically, a temperature rise of 50-70 degrees Fahrenheit is adequate for most households. Consider your local water temperature and desired hot water temperature to choose the right model.
Installation and VentingOutdoor tankless water heaters require proper installation and venting to ensure safe and efficient operation. Some models are easier to install and come with venting kits, while others may require professional installation. Consider the complexity of installation and whether you are comfortable doing it yourself or if you need professional help. Proper venting is crucial to prevent carbon monoxide buildup and ensure the heater operates efficiently. Check the installation requirements and choose a model that fits your installation capabilities.
Durability and Weather ResistanceSince outdoor tankless water heaters are exposed to the elements, durability and weather resistance are important factors. Look for models with robust construction, corrosion-resistant materials, and weatherproof features to ensure longevity. Some heaters come with protective enclosures or are designed to withstand extreme temperatures. If you live in an area with harsh weather conditions, prioritize models with high durability and weather resistance to ensure reliable performance.
Warranty and SupportA good warranty and reliable customer support can provide peace of mind and protect your investment. Warranties typically cover parts and labor for a certain period, and longer warranties indicate confidence in the product's quality. Check the warranty terms and the availability of customer support services. Choose a model with a comprehensive warranty and good support to ensure you can get help if any issues arise.