Tankless Water Heaters
Best Propane Tankless Water Heater (2026): 5 Picks Compared
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For this search, the APUS leads with 8.1 GPM and 190,000 BTU for 5-6 outlets, with app control and outdoor installation. The MIZUDO offers 10.3 GPM and the Rinnai reaches 11.1 GPM with built-in recirculation, while the Ranein covers 4-6 points and the Rheem covers whole-house use at 7 GPM. Match flow rate and fixture count to the home before choosing.
Starting out? See the main guide: Best Tankless Water Heater
Top picks at a glance
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Best OverallAPUS Propane Tankless Water Heater9.8 View on Amazon -
9.8 View on Amazon -
Highest Flow RateRinnai RXP199iN Condensing Smart Sense Tankless Water9.8 View on Amazon -
Also GreatRanein Propane Gas Tankless Water Heater9.6 View on Amazon -
Lightest PickRheem RTG Series 7.0 GPM Liquid Propane9.2 View on Amazon
Compare the specs
Ranked on flow rate, temperature control, phone app control from each listing, plus how many buyers have rated it. A dash (—) means we could not confirm that figure from the listing.
| Pick | Flow rate | Fuel | Temperature control | Phone app control | Weight | Warranty |
|---|---|---|---|---|---|---|
| 1. APUS Propane Tankless Water Heater | 8.1 GPM | Propane | Yes | Yes | 42.5 lb | 2-year |
| 2. MIZUDO Propane Gas Tankless Water Heater | 10.3 GPM | propane | Yes | Yes | 55.5 lb | 2-year |
| 3. Rinnai RXP199iN Condensing Smart Sense Tankless Water | 11.1 GPM | propane or natural gas | — | — | 58 lb | 5-year |
| 4. Ranein Propane Gas Tankless Water Heater | 8.5 GPM | Propane | — | — | 42 lb | 2-year |
| 5. Rheem RTG Series 7.0 GPM Liquid Propane | 7 GPM | Liquid Propane | Yes | — | 39.25 lb | 1-year |
APUS Propane Tankless Water Heater
8.1 GPM and 190,000 BTU for 5-6 outlets, with app control, a wired controller and outdoor installation.
- Flow rate: 8.1 GPM
- Fuel: Propane
- Temperature control
- Phone app control
- 2-year warranty stated
Good for
- Buyers with 5-6 outlets who want outdoor installation
- Buyers who want app control with a wired controller
Skip it if
- You need flow above 8.1 GPM
- You need hot water for more than 6 outlets
It adjusts from 95 to 149 degrees through the app or the wired controller, holding within 1 degree. The oxygen-free copper heat exchanger gives a UEF of 0.81, with freeze, overheat and flame failure protection included. It measures 22.48 by 15.51 by 6.54 inches, connects with standard 3/4-inch water and gas connections, and carries a 2-year full warranty.
MIZUDO Propane Gas Tankless Water Heater
10.3 GPM and 199,000 BTU for 5-7 outlets, with WiFi app control, Alexa compatibility and a 2-year full warranty.
- Flow rate: 10.3 GPM
- Fuel: propane
- Temperature control
- Phone app control
- 2-year warranty stated
Good for
- Buyers with 5-7 outlets who want indoor installation
- Buyers who want WiFi control with Alexa compatibility
Skip it if
- You need flow above 10.3 GPM
- You need use above 3,000 feet
It holds temperature within 1 degree up to 149 degrees, with a default 107-degree daily setting. Low-flow activation starts at 0.53 GPM, and the LED display works with the app for status checks and temperature changes. It measures 24.8 by 15.9 by 10.4 inches, carries CSA certification, and includes a 2-year full warranty with 5-year heat exchanger coverage.
Rinnai RXP199iN Condensing Smart Sense Tankless Water
11.1 GPM with built-in recirculation and dual-fuel propane or natural gas operation.
- Flow rate: 11.1 GPM, the highest here
- Fuel: propane or natural gas
- 5-year warranty stated
Good for
- Buyers with up to 7 fixtures at once
- Buyers who want recirculation that learns water use
Skip it if
- You need WiFi control without buying a separate module
- You need flow above 11.1 GPM
The internal pump recirculates water on a schedule it learns from household use, cutting hot water wait. It works indoors or outdoors with Versa Vent, though outdoor install needs the RX-OVC vent cap.
Ranein Propane Gas Tankless Water Heater
8.5 GPM and 190,000 BTU for 4-6 outlet points, with indoor wall mounting and a 2-year warranty.
- Flow rate: 8.5 GPM
- Fuel: Propane
- 2-year warranty stated
Good for
- Buyers with 4-6 outlet points who want indoor installation
- Buyers who want a compact wall-mounted unit
Skip it if
- You need flow above 8.5 GPM
- You need use above 2,000 feet
The blower sits underneath and adjusts speed with wind pressure and water temperature, helping prevent smoke backflow. It measures 24.25 by 15.08 by 8.07 inches and uses standard 3/4-inch water inlet fittings. In cold weather, open the pressure relief valve to drain leftover water if the unit sits unused, and it carries a 2-year warranty.
Rheem RTG Series 7.0 GPM Liquid Propane
Lightest here at 39.25 lb, with 7 GPM at a 35-degree rise and outdoor installation.
- Flow rate: 7 GPM
- Fuel: Liquid Propane
- Temperature control
- 1-year warranty stated
- 39.25 lb, the lightest here
Good for
- Buyers who want the lightest unit for outdoor wall mounting
- Buyers with 2-3 simultaneous showers
Skip it if
- You need flow above 7 GPM
- You need indoor installation
It delivers 7 GPM at a 35-degree rise with 160,000 BTU per hour, using a digital LED panel with 1-degree adjustments. Outdoor installation removes venting, and freeze and flame failure protection are built in. Mounting hardware is included, and it carries a 1-year labor warranty.
How to choose
Flow rate and fixture count
Flow rate sets how many outlets run at once. The Rinnai reaches 11.1 GPM for up to 7 fixtures, the MIZUDO reaches 10.3 GPM for 5-7 outlets, and the APUS and Ranein cover 8.1 GPM and 8.5 GPM for 5-6 and 4-6 points. The Rheem gives 7 GPM for 2-3 simultaneous showers. Count the showers, faucets and appliances that run together, then pick a flow rate that covers that total.
Fuel, venting and installation
The APUS, MIZUDO, Ranein and Rheem run on propane, while the Rinnai runs on propane or natural gas through its Smart Sense control. The APUS and Rheem install outdoors, and outdoor installation removes venting on the Rheem. The MIZUDO uses a sealed direct-vent system indoors, and the Rinnai works indoors or outdoors with Versa Vent, though outdoor install needs the RX-OVC vent cap. Professional installation is recommended for the MIZUDO and Rinnai.
Controls, freeze protection and upkeep
The Rinnai adds recirculation that learns household use, plus a Quick Flush feature for simplified flushing. For cold weather, drain leftover water through the pressure relief valve when the MIZUDO or Ranein unit sits unused. Check the altitude limits too: the MIZUDO is not recommended above 3,000 feet, and the Ranein is not recommended above 2,000 feet.
FAQ
What flow rate do I need for a whole house?
Match the flow rate to simultaneous use: the Rinnai reaches 11.1 GPM for up to 7 fixtures, the MIZUDO reaches 10.3 GPM for 5-7 outlets, and the Rheem gives 7 GPM for 2-3 simultaneous showers.
Do these heaters run on propane only?
The APUS, MIZUDO, Ranein and Rheem run on propane, while the Rinnai runs on propane or natural gas through its Smart Sense control.
Can I install a propane tankless heater outdoors?
The APUS and Rheem install outdoors, and the Rinnai works indoors or outdoors with Versa Vent, though outdoor install needs the RX-OVC vent cap. The MIZUDO and Ranein install indoors.
