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.

One of its standout features is the Smart-Circ Intelligent Recirculation system, which learns your hot water usage patterns and optimizes the recirculation to save energy and reduce wait times for hot water. Additionally, the high energy efficiency rating (UEF .98) means lower operating costs over time.

Installation is an important consideration; while it requires professional installation, the Rinnai Central App offers support for setup and troubleshooting, which can ease the learning curve for users. The heater is also designed for durability and can be installed outdoors with the proper venting, making it suitable for various environments. There are a few potential drawbacks. The need for professional installation may add to the cost, especially for those who prefer DIY projects. The unit is relatively compact but weighs 58 pounds, which might be cumbersome for some to handle during installation. Additionally, while the WiFi connectivity is a modern touch, the Control-R module is sold separately, which may be an extra expense for those wanting smart home integration.

The Rinnai RE160eN is a compact outdoor tankless water heater designed to deliver up to 6.6 gallons per minute (GPM), which can comfortably supply hot water to around five fixtures simultaneously. With a powerful 160,000 BTU rating, it offers strong heating capacity and can handle temperature rises effectively, making it suitable for most residential needs. This model is gas-powered and features high energy efficiency due to its smart design that heats water only when necessary, helping to reduce energy usage.

The built-in LED display is a useful feature, showing service reminders and error codes, which can simplify maintenance. It is designed for outdoor installation with durable construction to withstand weather conditions. Installation is recommended to be done by professionals, which can add to the overall cost and complexity. The warranty is a highlight, offering 15 years on the heat exchanger, 5 years on labor, and 1 year on parts, providing strong peace of mind.

As a non-condensing model, it may not be as energy-saving as condensing units. WiFi control is available but requires purchasing an additional module. This water heater is well-suited for homeowners seeking a reliable, energy-conscious outdoor unit with solid warranty coverage, particularly in moderate climates where outdoor installation is preferred.

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.

Installation is easier than many older models thanks to its smaller size and lighter weight, and it has a weather-resistant design suited for outdoor mounting. The heater supports WiFi, allowing you to monitor and control it remotely, which is convenient. Rheem’s hot-start programming prevents cold water bursts, improving your comfort. Its maximum temperature is 140°F, which covers most household needs.

This model is non-condensing, so it might be a bit less efficient compared to condensing units, especially in colder climates. The energy efficiency rating of 0.82 is good but not top-tier. Also, it requires a 1/2 inch gas line and proper venting for safe outdoor use, so professional installation is recommended. This Rheem model fits well if you want an efficient, space-saving, and easy-to-manage outdoor water heater. It is particularly suitable for homeowners looking to save energy and water while ensuring plenty of hot water on demand.