10 Best Outdoor Propane Tankless Water Heater 2025 in the United States

The Rinnai RXP199iN is a propane or natural gas tankless water heater designed for both indoor and outdoor use. It boasts an impressive flow rate of up to 11.1 gallons per minute (GPM), which is excellent for households with multiple fixtures needing hot water simultaneously. With a BTU rating of 199,000, it effectively heats water quickly, ensuring you won’t run out during peak usage times.

A standout feature is its high energy efficiency, rated at a UEF of .98, which means it uses energy wisely, potentially lowering your utility bills. The Smart Circ Intelligent Recirculation technology is a convenient addition, as it learns your hot water usage patterns, helping to minimize waste and keep hot water readily available.

While its compact size—similar to that of a small suitcase—makes it easy to install in various locations, professional installation is strongly recommended, which may add to your overall costs. The Rinnai Central App provides helpful tools for setup and troubleshooting, although the WiFi module is sold separately, which could be a drawback for those looking for a completely integrated smart system.

The FOGATTI Propane Tankless Water Heater is designed for outdoor installation and offers an impressive flow rate of up to 5.1 gallons per minute (GPM). With a BTU rating of 120,000, this unit can efficiently supply hot water to multiple points in a household, making it ideal for families.

This tankless water heater stands out for its precise temperature control, capable of maintaining water temperature within a 1°F margin, which is beneficial throughout the year. Additionally, its compact size (23.9)

The Rinnai RXP160iN is a versatile tankless water heater suitable for both indoor and outdoor use, powered by either propane or natural gas. It delivers a strong flow rate of up to 9 gallons per minute, enough to supply hot water to multiple fixtures simultaneously, which is great for medium to large households. With a high BTU rating of 160,000, it heats water quickly and efficiently, and its energy factor of 0.97 means it wastes very little energy compared to traditional heaters. You can adjust the temperature up to 140°F, offering flexibility for different needs.

This model stands out with its Smart Sense gas control and Smart-Circ recirculation pump that learns your water usage patterns to save energy and reduce wait times for hot water. It also features an easy-to-use interface and a Quick Flush option for easier maintenance. However, it weighs 57 pounds and is about the size of a small suitcase, so while it’s portable in that sense, it still requires a sturdy wall mount and professional installation, which might add to the initial costs.

Safety features are solid, but the product doesn’t come with built-in WiFi control—though you can add an optional Controlr module for remote operation. Considering the unit’s price and installation needs, its efficiency, smart technology, and ability to work both indoors and outdoors make it a smart choice for those wanting a reliable, energy-saving water heater that can handle busy households.