If you’re looking for endless hot water without taking up valuable indoor space, an outdoor propane tankless water heater might be exactly what you need. Designed to handle the elements, these units mount outside your home and deliver a steady flow of hot water whenever you need it. They’re especially popular for homes in milder climates, vacation cabins, and even larger properties where venting an indoor unit might be difficult.
In this guide, we’ll explore the best outdoor propane tankless water heaters for 2025, what makes them great, and how to choose the right one for your needs. We’ll also cover installation, maintenance tips, and a crucial but often-overlooked part of your home’s plumbing system that can save you thousands of dollars in repairs.
Why Choose an Outdoor Propane Tankless Water Heater?
Compared to indoor models, outdoor propane tankless heaters offer some distinct advantages:
- No indoor space needed: Frees up room inside your home.
- Simpler installation: No venting required since exhaust dissipates outside.
- Flexible placement: Can be mounted close to where hot water is most needed to reduce wait time.
- High performance: Delivers hot water on demand, even for larger households.
The main consideration is weather. If you live in a region with freezing winters, you’ll need a model with built-in freeze protection or a plan to winterize it.
Best Overall: Rinnai RL75eP Outdoor Tankless Water Heater
The Rinnai RL75eP is a standout choice for homeowners who want reliable hot water without the hassle of indoor venting.
- Flow rate: 7.5 GPM – enough for two to three simultaneous showers.
- Fuel: Propane.
- Design: Weather-resistant casing with built-in freeze protection.
- Efficiency: High efficiency with low NOx emissions.
This model is perfect for small to medium households in climates that don’t drop below extreme temperatures for long periods.
Other Top Outdoor Propane Tankless Water Heaters
Rinnai V65eP
Compact and affordable, the V65eP offers 6.5 GPM of hot water output, making it ideal for smaller homes, cabins, or vacation properties.
Noritz NR83ODLP
This unit delivers 8.3 GPM and is built with a durable stainless steel heat exchanger for long-lasting performance.
Takagi T-KJr2-OS-P
Compact yet powerful, the Takagi outdoor propane tankless heater is great for mild climates and offers excellent value for its output capacity.
Camplux 10L Outdoor Portable Propane Water Heater
Perfect for seasonal use or off-grid cabins, this portable unit is budget-friendly and easy to install for temporary setups.
Key Features to Look for in an Outdoor Propane Tankless Heater
When shopping for the right unit, consider the following:
- Flow rate (GPM): Match the output to your household’s peak hot water demand.
- Weather protection: Look for models with freeze protection and durable casings.
- Installation location: Place near high-demand areas to shorten wait time for hot water.
- Efficiency rating: ENERGY STAR® certified units save money over time.
Pro Tip: If you live in a colder climate, consider adding an insulated enclosure or seasonal drain-down procedure to prevent freeze damage.
Installation Considerations
Outdoor propane tankless heaters are easier to install than indoor models because they don’t require venting. However, professional installation is still recommended for:
- Safe propane line connection and leak testing.
- Mounting securely to an exterior wall.
- Setting up freeze protection systems if needed.
Maintenance Tips
Even outdoor models require upkeep to maintain peak performance:
- Flush the heat exchanger annually to remove mineral buildup.
- Inspect propane lines regularly for leaks.
- Check weather seals and insulation around the unit.
Following these steps can help your outdoor propane tankless heater last 15–20 years or more.
The Overlooked Side of Your Plumbing System
Installing the best outdoor propane tankless water heater ensures endless hot water, but what about what happens after that water leaves your home? If you have a septic system, neglecting maintenance can lead to slow drains, foul odors, and expensive backups.
Many homeowners only think about their septic system when something goes wrong—which is often too late to avoid costly repairs.
SEPTIFIX – Protect Your Septic System Easily
SEPTIFIX is the #1 septic tank treatment in the US. These easy-to-use tablets dissolve in your toilet, releasing oxygen and beneficial bacteria that break down waste, sludge, and grease while eliminating odors.
Benefits include:
- Removes foul odors within days.
- Prevents costly pump-outs and septic failures.
- Safe for all septic systems and environmentally friendly.
- Just flush one tablet per month—no mess or measuring.
By combining a quality propane tankless heater with regular SEPTIFIX use, you protect your comfort and your investment.
Final Thoughts
In 2025, the Rinnai RL75eP is our top pick for the best outdoor propane tankless water heater thanks to its durability, efficiency, and performance. The Rinnai V65eP, Noritz NR83ODLP, Takagi T-KJr2-OS-P, and Camplux 10L also offer excellent options depending on your needs and budget.
And remember—endless hot water is just one part of a comfortable home. Keep your septic system healthy with SEPTIFIX to ensure your plumbing stays trouble-free year-round.
Order SEPTIFIX Today – Keep Your Septic Tank in Top Condition
Hot water whenever you need it, plus a healthy septic system—that’s peace of mind you can count on.