10 Best Outdoor Propane Tankless Water Heater 2026 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 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.

The Rinnai RX180iN tankless water heater is a versatile option suitable for both indoor and outdoor use, supporting propane or natural gas fuel. It delivers a strong flow rate of up to 10 gallons per minute, supplying hot water to about six fixtures at once—ideal for medium to large homes or those with higher hot water demand. With a powerful heat output of 180,000 BTUs, it heats water quickly and consistently. Its temperature range goes up to 140°F, allowing for customizable comfort.

The unit boasts very high energy efficiency, with a UEF rating of 0.98, meaning it wastes very little energy compared to traditional heaters. The ignition system is modern and user-friendly, and the Smart Sense gas control adds safety and efficiency by adjusting to the fuel type automatically. Installation requires a professional, especially for outdoor setups where an additional vent cap is needed. The heater is compact and wall-mountable—roughly the size of a small suitcase—making it relatively easy to fit into tight spaces, though at 54 pounds it’s not something you’d move frequently. It also offers smart home compatibility for remote control, adding convenience.

The need for professional installation might add to upfront costs, and the warranty requires registration within 90 days to get the full labor coverage. This model is well suited for homeowners seeking a reliable, energy-efficient water heater with flexible fuel options and modern features.