An outdoor propane tankless water heater can free up indoor space and supply hot water on demand—but the right unit depends on where you’ll use it and how many fixtures may run at once.
These 10 picks span permanently installed home units and portable models for cabins or outdoor showers. Compare flow ratings, installation requirements, and cold-weather features before you buy.
Best 10 Outdoor Propane Tankless Water Heaters Picks for 2026
Best for Multiple Fixtures
Westinghouse 8.1 GPM Outdoor Propane Heater
- Up to 8.1 GPM; 180,000 BTU
- Designed for three to five fixtures
- Wired controller and freeze protection
Best For: Homes running several hot-water fixtures
Best for App Control
APUS 8.1 GPM Outdoor Propane Heater
- Up to 8.1 GPM; 190,000 BTU
- Tuya app and wired controls
- 0.79 GPM minimum activation flow
Best For: Larger households wanting connected controls
Best for Moderate Demand
FOGATTI 5.1 GPM Outdoor Propane Heater
- Up to 5.1 GPM; 120,000 BTU
- Designed for two to four outlets
- Indoor remote panel; CSA-certified
Best For: Medium-size homes with moderate demand
Best for a Slim Installation
Ranein 5.3 GPM Outdoor Propane Heater
- Up to 5.3 GPM; 130,000 BTU
- Shallow 5.7-inch listed depth
- Wired controller and freeze protection
Best For: Outdoor walls with limited mounting depth
Best for Multiple Outlets
CAMPLUX 6.4 GPM Outdoor Propane Heater
- Up to 6.4 GPM rated flow
- Designed for steadier water temperature
- CSA-certified with multiple safety protections
Best For: Homes serving several hot-water outlets
Best Compact Pick
Rinnai V53DeP Outdoor Propane Heater
- 5.3 GPM rated flow
- 13-inch-wide wall-mounted cabinet
- Enhanced scale detection
Best For: Space-limited outdoor installations
Best for Higher Flow
Rheem RTG 7.0 GPM Outdoor Propane Heater
- 7.0 GPM at a 35°F rise
- Outdoor wall-mounted design
- 15-year heat-exchanger warranty listed
Best For: Multi-bathroom homes needing higher flow
Best for Home Installation
MIZUDO 5.1 GPM WiFi Propane Water Heater
- Rated 5.1 GPM and 120,000 BTU
- WiFi temperature and usage controls
- Outdoor conversion kit sold separately
Best For: Homes needing multi-fixture hot water and app controls
Best for Portable Showers
GASLAND BS318 3.18 GPM Water Heater
- Rated 3.18 GPM flow
- Starts at 3.6 PSI
- Shower head and regulator included
Best For: Camping and off-grid outdoor showers
Best Higher-Flow Camping Pick
CAMPLUX BW422G 4.22 GPM Water Heater
- Rated 4.22 GPM and 110,000 BTU
- Battery powered; starts at 4.0 PSI
- LED display and adjustable controls
Best For: Higher-flow off-grid outdoor showers
Best for Multiple Fixtures – Westinghouse 8.1 GPM Outdoor Propane Heater
Among outdoor propane tankless water heaters, this Westinghouse model is a strong fit for homes that run several fixtures at once. Its rated maximum is 8.1 GPM and 180,000 BTU, with a wired controller for adjusting the water temperature.
Best For: Households planning to supply three to five fixtures from an outdoor-mounted unit.
Pros:
- Rated for up to 8.1 GPM and 180,000 BTU.
- Self-modulating controls are designed to keep outlet temperature within ±1°F.
- CSA-certified, with integrated freeze protection and a five-year heat-exchanger warranty.
Cons:
- Requires 120V AC power in addition to propane.
- Its 17.1-inch-wide, 26.8-inch-high cabinet needs adequate outdoor wall space.
The wired controller and stated temperature stability make this a practical choice when shower comfort matters as much as fixture capacity. Check your plumbing and gas setup against the installation requirements before buying.
Best for App Control – APUS 8.1 GPM Outdoor Propane Heater
If you want connected controls in an outdoor propane tankless water heater, the APUS pairs Tuya app control with a wired controller. It is rated for up to 8.1 GPM and 190,000 BTU, and its stated minimum activation flow is 0.79 GPM.
Best For: Larger households seeking app-based temperature adjustment and hot water for multiple outlets.
Pros:
- Manufacturer specifies supply for five to six outlets, with a maximum 8.1 GPM flow rate.
- Tuya app and wired-controller options offer flexible temperature adjustment from 95°F to 149°F.
- Includes freeze, overheat, and flame-failure safeguards.
Cons:
- Needs a 120V AC power connection.
- The listed maximum temperature is 149°F, lower than some other models in this roundup.
The low stated activation flow is worth considering if smaller draws are common in your home. As with any maximum flow rating, assess your expected simultaneous demand before sizing the unit.
Best for Moderate Demand – FOGATTI 5.1 GPM Outdoor Propane Heater
The FOGATTI is one of the more moderately sized outdoor propane tankless water heaters here, rated at 5.1 GPM and 120,000 BTU. Its stated two-to-four-outlet coverage makes it worth considering when you do not need the higher flow rating of an 8.1 GPM model.
Best For: Medium-size households with moderate simultaneous hot-water demand.
Pros:
- Water-servo controls are designed to maintain temperature within ±1°F.
- Remote control panel allows adjustment from indoors.
- CSA-certified, with two-year full-unit and five-year heat-exchanger coverage.
Cons:
- Manufacturer recommends use below 2,000 feet of altitude.
- Despite active freeze protection, draining is recommended below 5°F or during extended nonuse.
This model balances a smaller flow rating with precise controls and indoor adjustment. Pay particular attention to the cold-weather guidance if the installation site sees prolonged freezes.
Best for a Slim Installation – Ranein 5.3 GPM Outdoor Propane Heater
For buyers comparing outdoor propane tankless water heaters by mounting space, the Ranein has a listed depth of just 5.7 inches. It is rated at a maximum 5.3 GPM and 130,000 BTU, with an included wired digital controller.
Best For: Outdoor wall installations where a shallow cabinet and moderate flow rating are priorities.
Pros:
- 5.7-inch listed depth and 34-pound listed weight.
- Standard 3/4-inch NPT water and gas inlet connections.
- Includes anti-freeze protection and a blower that adjusts speed in response to operating conditions.
Cons:
- Not recommended for areas above 2,000 feet.
- Manufacturer advises draining remaining water during prolonged cold-weather nonuse.
Although the listing describes use at three to five water points, the 5.3 GPM maximum is the more useful figure for comparing capacity. Confirm that your likely simultaneous fixtures fit within that rating.
Best for Multiple Outlets – CAMPLUX 6.4 GPM Outdoor Propane Heater
Among outdoor propane tankless water heaters, this CAMPLUX model is a strong option for homes that need hot water at several fixtures. It is rated for up to 6.4 GPM, though actual flow depends on the required temperature rise.
Best For: Households planning an outdoor installation to serve multiple bathrooms and other hot-water outlets.
Pros:
- Rated for up to 6.4 GPM, with a stated 5.28 GPM operating figure.
- Temperature-control system is designed to limit fluctuations to ±1°F.
- CSA-certified, with freeze, overheat, dry-fire, and flame-failure protections.
Cons:
- Requires a 120V electrical connection.
- The maximum flow rating does not indicate how much hot water it will deliver at every inlet temperature.
Check your expected inlet-water temperature and simultaneous fixture demand before sizing it for the whole house. Its outdoor, wall-mounted design avoids an indoor vent run.
Best Compact Pick – Rinnai V53DeP Outdoor Propane Heater
The Rinnai V53DeP is a compact choice among outdoor propane tankless water heaters when wall space matters. Its 5.3 GPM rating offers on-demand hot water without the footprint of a storage tank.
Best For: Buyers seeking a space-saving outdoor unit with moderate household hot-water demand.
Pros:
- Compact wall-mounted cabinet measures 13 inches wide and 7.9 inches deep.
- Heats water on demand rather than maintaining a stored supply.
- Enhanced scale detection is listed among its features.
Cons:
- Its 5.3 GPM rating is lower than the other two models in this roundup.
- Warranty terms in the supplied product information conflict; verify current coverage and registration requirements before buying.
Have a qualified technician assess whether its flow rating fits your fixtures and install the unit. Its main appeal is fitting an outdoor propane heater into a relatively narrow space.
Best for Higher Flow – Rheem RTG 7.0 GPM Outdoor Propane Heater
For buyers comparing outdoor propane tankless water heaters by flow, the Rheem RTG has a stated 7.0 GPM output at a 35°F temperature rise. That makes it worth considering for homes with multiple showers, provided local inlet temperatures and fixture demand support the sizing.
Best For: Multi-bathroom households seeking a higher stated flow rate from an outdoor-mounted unit.
Pros:
- Rated for 7.0 GPM at a specified 35°F temperature rise.
- Outdoor installation eliminates the need for an indoor vent run.
- Includes freeze and flame-failure protections, plus a digital temperature display.
- Listed warranty covers the heat exchanger for 15 years, parts for 5 years, and labor for 1 year.
Cons:
- Professional installation is required.
- Available flow will decrease when a larger temperature rise is needed.
The published flow figure is useful because it includes its temperature-rise condition. Confirm performance against your winter inlet-water temperature before counting on simultaneous showers.
Best for Home Installation – MIZUDO 5.1 GPM WiFi Propane Water Heater
Among outdoor propane tankless water heaters, this MIZUDO model is the home-oriented option: it offers a rated 5.1 GPM flow and app-based controls. It can be installed indoors or converted for outdoor use, but either setup requires the appropriate separately purchased vent components.
Best For: Homeowners who want a wall-mounted propane heater for multiple fixtures and are prepared to plan the installation.
Pros:
- Rated at 120,000 BTU and up to 5.1 GPM for 2 to 4 usage points.
- WiFi app supports temperature adjustments, energy monitoring, and maintenance notifications.
- CSA certified, with freeze, flame-failure, dry-burn, and exhaust-blockage protections.
Cons:
- Outdoor installation requires a separately purchased vent-cap conversion kit.
- Requires a 120V electrical connection.
Choose this over a portable shower unit when multi-fixture capacity and remote controls matter more than quick setup. Confirm the required installation parts before ordering.
Best for Portable Showers – GASLAND BS318 3.18 GPM Water Heater
For shoppers comparing outdoor propane tankless water heaters for camping or cabin use, the GASLAND BS318 pairs a rated 3.18 GPM flow with battery-powered ignition. It runs from a standard 20-pound propane tank and includes a shower head, regulator, and hose.
Best For: Portable outdoor showers, pet washing, and off-grid spots with at least 3.6 PSI of water pressure.
Pros:
- Starts at water pressure as low as 3.6 PSI.
- Two D-cell batteries power ignition, so no electrical hookup is needed.
- Includes a CSA-certified gas regulator and hose, shower head, and mounting hardware.
Cons:
- Not recommended for locations above 3,300 feet or for strong winds.
- Prolonged rain exposure can damage components; drain and store it somewhere warm and dry for winter.
This is a practical pick when portability and a ready-to-use shower package outweigh permanent-installation features. Plan for dry storage between uses.
Best Higher-Flow Camping Pick – CAMPLUX BW422G 4.22 GPM Water Heater
The CAMPLUX BW422G stands out among outdoor propane tankless water heaters for its rated 4.22 GPM flow and battery-powered operation. Its LED temperature display and separate water and gas controls make it a flexible option for outdoor showers, poolside use, and remote cabins.
Best For: Buyers who want a higher-flow outdoor shower heater without an electrical hookup.
Pros:
- Rated at 110,000 BTU and up to 4.22 GPM.
- Starts at 4.0 PSI and uses battery-powered ignition.
- Includes a shower head and CSA-certified gas regulator.
- LED display and adjustable controls help set the outgoing water temperature.
Cons:
- At 26.6 pounds, it is a substantial unit to carry and mount.
- Requires at least 4.0 PSI of water pressure to start.
Consider it if you want more rated flow than a smaller portable shower model while keeping off-grid operation. Check your water pressure and mounting location before buying.
How We Picked the Best Outdoor Propane Tankless Water Heaters
We considered the listed flow rates and BTU inputs, intended installation type, and features relevant to outdoor use. The selection covers higher-output units for permanent home installations, midrange options, and portable heaters for occasional use. Published specifications are starting points, not guarantees: actual hot-water flow depends on incoming water temperature and the temperature rise you need.
Quick Comparison: Match the Heater to the Job
For a permanent home installation with more than one potential hot-water demand, start by comparing the Westinghouse and APUS models listed at 8.1 GPM, along with the 7.0 GPM Rheem. The CAMPLUX 6.4 GPM model and Ranein 5.3 GPM model sit in the middle of the listed output range. For a smaller setup, compare the MIZUDO 5.1 GPM unit with the Rinnai V53DeP and FOGATTI after checking their applicable specifications. The portable GASLAND BS318 and CAMPLUX BW422G are better starting points for a shower or other temporary outdoor use—not automatic substitutes for a plumbed household system.
Key Buying Factors for Outdoor Propane Tankless Water Heaters
Flow Rate and Temperature Rise
Add up the flow rates of fixtures you expect to use simultaneously, then check the manufacturer’s flow chart at your required temperature rise. A headline GPM figure may reflect warmer incoming water; performance can drop substantially in colder climates. Higher BTU input can support greater heating output, but it also increases fuel-supply demands.
Permanent Installation Versus Portable Use
Confirm that the exact model is approved for your intended outdoor installation. A fixed heater may need properly sized gas piping, approved water connections, electrical power, and clearances from doors, windows, and vents. Portable shower heaters have different mounting, water-pressure, and use restrictions; follow their manuals rather than assuming they are suitable for indoor fixtures or continuous household service.
Climate, Water Supply, and Ongoing Costs
Check freeze-protection instructions carefully. Built-in protection, when present, may require continuous power and may not protect exposed pipes during an outage. Also verify the unit’s minimum activation flow and operating water-pressure range, especially for a well, pump, or gravity-fed supply. Budget for propane delivery or cylinder changes, any required electrical connection, water filtration where needed, and periodic maintenance.
Who Should Buy Which Outdoor Propane Tankless Water Heaters?
Choose a higher-output, permanently installed model if you need to serve multiple fixtures and your gas supply can support it. Consider a midrange model when simultaneous demand is modest and you want to avoid oversizing. Choose a portable model for camping, an outdoor rinse station, or intermittent cabin use only when its instructions explicitly permit your setup. Before ordering any outdoor propane tankless water heater, have a qualified installer confirm local code requirements, gas capacity, placement, and the flow you can expect in your climate.