10 Best Outdoor Tankless Water Heaters 2026 in the United States

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.

The Rheem RTG-95XELN-3 is a solid choice if you need an outdoor tankless water heater that delivers continuous hot water for your whole house, with a strong flow rate of 9.5 gallons per minute. This means it can handle several fixtures at once, like showers and dishwashers, without running out of hot water. It is designed to be energy efficient, operating only when hot water is needed, which helps reduce energy bills. You’ll also appreciate the water-saving feature that can cut down water waste by up to 1,100 gallons a year.

The Rinnai RE199eP is a well-built outdoor propane tankless water heater designed to supply continuous hot water for multiple fixtures, with a maximum flow rate of up to 9.8 gallons per minute. Its 199,000 BTU rating means it can handle strong temperature rises, making it suitable for homes in colder climates or those with higher hot water demands. The heater features a smart design that heats water only when needed, which helps save energy without sacrificing comfort. The LED display is a user-friendly touch, offering maintenance reminders and error codes to make troubleshooting easier.