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The Rinnai 5.3 GPM Outdoor Propane Tankless Water Heater delivers endless hot water with a compact footprint. It suits outdoor residential use where brand reliability and space-saving design matter most. However, you might seek different specifications, such as higher flow rates, indoor installation options, or advanced features like smart controls. These factors define the search for rinnai 5 3 gpm outdoor propane alternatives.
This list covers 6 models selected because their core specs overlap with the original unit. We compare flow capacity, fuel type, and installation requirements to help you find a better fit. Some alternatives offer greater simultaneous fixture capacity for larger households. Others provide indoor safety features or remote temperature adjustment. Each option is ranked by how well it matches specific needs while maintaining propane efficiency. You can review the technical data to determine which unit aligns with your household’s hot water demands.
01 How each alternative compares
Rinnai 6.1 GPM Outdoor Propane Water Heater
The Rinnai 6.1 GPM model offers a higher flow rate of 6.6 GPM compared to the original 5.3 GPM. This allows it to support five simultaneous fixtures, whereas the original supports multiple appliances with slightly less volume. It shares the compact, outdoor propane design and brand reliability. You gain flow speed but accept a slightly larger footprint at 14.1 inches wide versus 13 inches. Choose this if you need more hot water for busy households without switching fuel types.
Rinnai RXP160iN Condensing Tankless Heater
The Rinnai RXP160iN Condensing Tankless Heater delivers 9 GPM, significantly outpacing the original 5.3 GPM. It includes a booster pump for enhanced performance in large homes. While it maintains the outdoor propane format, it is heavier at 57 pounds and wider at 19 inches. This model prioritizes high capacity and efficiency over the compact size of the original. Select it if you require maximum flow for multiple bathrooms and appliances, and have the space for a larger unit.
Ranein 3.6 GPM Indoor Propane Tankless Heater
The Ranein 3.6 GPM unit shifts from outdoor to indoor installation, making it suitable for homes where exterior mounting is not an option. It has a lower flow rate of 3.6 GPM, limiting it to two to three simultaneous fixtures compared to the original. It is lighter at 18 pounds and similar in width. This choice fits small to medium homes prioritizing indoor safety and stable temperatures over high volume. You trade flow speed for flexible indoor placement.
APUS 80,000 BTU Indoor Propane Tankless Heater
The APUS 80,000 BTU heater is designed for indoor use, differing from the outdoor-only original. It provides 3.6 GPM, which is lower than the original 5.3 GPM. Its compact form factor suits small households needing precise temperature control for two to three points. Weighing 19.2 pounds, it is lighter than the original. This model is ideal if you need indoor installation and value efficiency and stability over the higher flow capacity of the Rinnai outdoor unit.
MIZUDO 180K BTU Propane Tankless Heater
The MIZUDO 180K BTU heater offers 8.1 GPM, nearly double the original 5.3 GPM. It is intended for whole-house use in large households with high simultaneous demands. It includes remote control and precise temperature settings for added convenience. The unit is 17.1 inches wide, slightly narrower than the original, but lacks specified weight data. Choose this if you need high-volume hot water and smart controls, accepting the higher capacity and different feature set compared to the standard outdoor model.
APUS 8.1 GPM Propane Outdoor Heater
The APUS 8.1 GPM Propane Outdoor Heater matches the outdoor installation location of the original but delivers 8.1 GPM. This higher flow rate supports busy households with multiple simultaneous outlets. It features smart app control, which the original data does not list. At 6.54 inches wide, it is significantly narrower than the original 13-inch width. Weighing 42.5 pounds, it is heavier. Pick this if you need high-volume outdoor hot water with modern smart connectivity and a slim profile.
| # | Product | Best for | Price |
|---|---|---|---|
| 1 | Rinnai 5.3 GPM Outdoor Propane Tankless Water Heater Best overall | outdoor residential propane hot water | |
| 2 | Rinnai 6.1 GPM Outdoor Propane Water Heater Also great | outdoor use with five simultaneous fixtures | |
| 3 | Rinnai RXP160iN Condensing Tankless Heater Best premium | large homes needing high flow and efficiency | |
| 4 | Ranein 3.6 GPM Indoor Propane Tankless Heater Best budget | indoor homes needing stable hot water | |
| 5 | APUS 80,000 BTU Indoor Propane Tankless Heater Also great | Indoor 2–3 point hot water needs | |
| 6 | MIZUDO 180K BTU Propane Tankless Heater Best whole house | large households with high simultaneous hot water demands | |
| 7 | APUS 8.1 GPM Propane Outdoor Heater Also great | High-volume outdoor multi-outlet use |
Rinnai 5.3 GPM Outdoor Propane Tankless Water Heater
Best for: outdoor residential propane hot water
- Fuel Type
- Propane
- Max Flow Rate
- 5.3 GPM
- Installation Location
- Outdoor
- Fixture Capacity
- multiple appliances
- Features
- Tankless
- Form Factor
- Compact
This Rinnai V53DeP is a compact outdoor propane tankless water heater delivering 5.3 GPM. It heats water on demand, saving space and energy. The unit measures 13 by 13 by 30 inches and weighs 33 pounds. It suits households needing endless hot water for multiple appliances. Professional installation is recommended for safety and performance.
- 5.3 GPM max flow rate for multiple appliances
- Compact 13x13x30 inch design fits tight spaces
- Energy-efficient on-demand heating reduces waste
- 10-year heat exchanger warranty included
- 5.3 GPM flow rate is lower than 6.1 GPM and 9 GPM alternatives
- 33-pound weight is heavier than some compact indoor units
- Outdoor installation only limits placement options
- You need a compact outdoor propane heater
- You want reliable hot water for multiple fixtures
- You prefer a trusted brand with strong warranty
- You require indoor installation only
- You need a flow rate above 5.3 GPM
- You want a lighter, portable unit
Verdict: Rinnai V53DeP 5.3 GPM Outdoor Propane is a solid choice for outdoor residential use. It fits well if you value compact size and brand reliability over maximum flow speed.
Rinnai 6.1 GPM Outdoor Propane Water Heater
Best for: outdoor use with five simultaneous fixtures
- Fuel Type
- Propane
- Max Flow Rate
- 6.1 GPM
- Heating Capacity
- 160k BTU
- Installation Location
- Outdoor
- Fixture Capacity
- 5 fixtures at once
- Features
- Tankless
The Rinnai RE160eP delivers 6.1 GPM of hot water using 160k BTU propane. This compact outdoor unit fits five fixtures at once. Its 49.2-pound frame fits in small spaces. The LED screen shows error codes and service reminders. You get a 15-year heat exchanger warranty. Professional installation is recommended for safety and performance.
- 6.1 GPM flow rate supports five fixtures simultaneously
- 160k BTU heating capacity for consistent hot water
- Compact 14.1-inch width fits tight outdoor spaces
- 15-year limited warranty on the heat exchanger
- 6.1 GPM flow is lower than the 8.1 GPM models on this list
- 160k BTU output is less than the 180k and 190k BTU competitors
- WiFi control requires a separate Controlr module purchase
- You need a reliable Rinnai unit for outdoor use
- You want to run up to five fixtures at once
- You prefer a compact heater that fits in small areas
- You require more than 6.1 GPM of hot water
- You need higher than 160k BTU heating power
- You want built-in WiFi without buying extra parts
Verdict: Rinnai RE160eP Outdoor Propane Heater provides steady hot water for households needing five fixtures. It suits buyers who prioritize brand reliability and compact sizing over maximum flow rate.
Rinnai RXP160iN Condensing Tankless Heater
Best for: large homes needing high flow and efficiency
- Fuel Type
- Natural Gas, Propane
- Max Flow Rate
- 9 GPM
- Heating Capacity
- 160k BTU
- Installation Location
- Indoor, Outdoor
- Fixture Capacity
- 6 fixtures
- Features
- Tankless, Booster Pump
This Rinnai unit delivers up to 9 GPM at 160,000 BTU, supporting six fixtures. It works indoors or outdoors with propane or natural gas. The compact 19 by 31 inch design includes a built-in recirculation pump. Smart-Circ technology learns your usage to save energy. It offers a high 0.97 UEF rating. This model suits large homes needing high flow and smart efficiency.
- 9 GPM max flow rate for six fixtures
- 160,000 BTU heating capacity
- Built-in Smart-Circ recirculation pump
- 0.97 UEF energy efficiency factor
- Dual fuel compatibility with propane and natural gas
- 57-pound weight is heavier than non-condensing models
- 31-inch height requires more vertical space
- WiFi Controlr module sold separately
- You need hot water for six simultaneous fixtures
- You want high energy efficiency with a 0.97 UEF
- You prefer a built-in recirculation pump for convenience
- You have limited vertical space for a 31-inch unit
- You cannot support a 57-pound installation
- You want WiFi control included in the base price
Verdict: Rinnai RXP160iN Condensing Tankless Heater provides top-tier flow and efficiency for large households. It fits buyers who prioritize high capacity and smart recirculation over compact size.
Ranein 3.6 GPM Indoor Propane Tankless Heater
Best for: indoor homes needing stable hot water
- Fuel Type
- Propane Gas
- Max Flow Rate
- 3.6 GPM
- Heating Capacity
- 80,000 BTU
- Installation Location
- Indoor
- Fixture Capacity
- 2-3 water points
- Temperature Range
- 95°F-149°F
The Ranein is an indoor propane tankless water heater rated at 80,000 BTU and 3.6 GPM. It supports two to three water points simultaneously. The unit features a 95°F to 149°F adjustable temperature range and dual heating chambers. It includes preset modes for specific uses and built-in anti-freeze protection. This model suits homes needing reliable indoor hot water with precise temperature control.
- 80,000 BTU heating capacity for consistent hot water
- 3.6 GPM flow rate supports 2-3 fixtures
- 95°F-149°F adjustable temperature range prevents spikes
- Dual heating chambers improve efficiency and stability
- Includes vent pipe for easier installation
- Lower 3.6 GPM flow rate than other options on this list
- Indoor-only installation limits placement flexibility
- Heavier 18-pound build compared to compact outdoor units
- You need a dedicated indoor propane water heater
- You want precise temperature control for sensitive skin
- You require a unit that includes the vent pipe
- You need outdoor installation capability
- You require a flow rate above 4.3 GPM
- You want a lighter unit for easy mounting
Verdict: Ranein 3.6 GPM Propane Indoor Heater fits households prioritizing indoor safety and stable temperatures over high flow rates. It is ideal for small to medium homes with two to three simultaneous water needs.
APUS 80,000 BTU Indoor Propane Tankless Heater
Best for: Indoor 2–3 point hot water needs
- Fuel Type
- Propane
- Max Flow Rate
- 3.6 GPM
- Heating Capacity
- 80,000 BTU
- Installation Location
- Indoor
- Voltage
- 120 V AC
- Fixture Capacity
- 2–3 Points
This APUS indoor propane tankless water heater delivers 3.6 GPM at 80,000 BTU. It targets 2–3 water points with a temperature range of 95–149°F. The unit features an oxygen-free copper heat exchanger for efficient heating. Its compact design fits tight spaces, and the LED display shows set temperatures. It requires indoor venting by a licensed professional.
- 3.6 GPM max flow rate for multiple fixtures
- 95–149°F temperature control with ±1°F precision
- Oxygen-free copper heat exchanger for efficiency
- Compact wall-mount design for tight spaces
- Anti-freeze protection activates near 41°F
- Lower 3.6 GPM flow rate compared to 5.3–9 GPM alternatives
- Indoor-only installation limits outdoor flexibility
- Heavier 19.2-pound build than some compact units
- You need hot water for 2–3 points in a home
- You require precise temperature control within ±1°F
- You have limited indoor space for wall mounting
- You need outdoor installation capabilities
- You require a flow rate above 3.6 GPM
- You prefer a lighter unit under 19 pounds
Verdict: APUS 3.6 GPM Propane Indoor Heater suits small households needing precise, efficient indoor hot water. It fits users prioritizing temperature stability and compact sizing over high flow rates.
MIZUDO 180K BTU Propane Tankless Heater
Best for: large households with high simultaneous hot water demands
- Fuel Type
- Propane
- Max Flow Rate
- 8.1 GPM
- Heating Capacity
- 180,000 BTU
- Installation Location
- Outdoor
- Voltage
- 120V
- Fixture Capacity
- 3–5 outlets
This outdoor propane unit delivers 8.1 GPM at 180,000 BTU. It handles 3–5 fixtures with precise temperature control within ±1°F. The low-flow activation starts at 0.53 GPM for efficiency. You get a large LED display and remote control for easy adjustments. It fits busy households needing whole-house hot water without the bulk of a tank.
- High 8.1 GPM flow rate for multiple bathrooms
- 180,000 BTU heating capacity for rapid heating
- ±1°F precise temperature control reduces fluctuations
- Remote control with large LED display
- 2-year full unit warranty is shorter than typical industry standards
- Not recommended for elevations above 2,000 feet
- Requires professional installation for gas connections
- You need hot water for 3–5 simultaneous fixtures
- You want precise temperature control for soaking tubs
- You prefer remote adjustment via LED display
- You live above 2,000 feet elevation
- You need a unit for indoor installation only
- You want a longer than 2-year full warranty
Verdict: MIZUDO 8.1 GPM Propane Tankless suits large households with high simultaneous hot water demands. Its remote control and precise temperature settings make it ideal for users prioritizing comfort and convenience over extended warranty coverage.
APUS 8.1 GPM Propane Outdoor Heater
Best for: High-volume outdoor multi-outlet use
- Fuel Type
- Propane
- Max Flow Rate
- 8.1 GPM
- Heating Capacity
- 190,000 BTU
- Installation Location
- Outdoor
- Voltage
- 120V AC
- Fixture Capacity
- 5–6 outlets
The APUS propane tankless water heater delivers 190,000 BTU and 8.1 GPM for outdoor use. It supports 5–6 outlets simultaneously with precise temperature control. The unit features Wi-Fi app management and a compact outdoor design. It suits homes needing high-volume hot water for multiple fixtures at once.
- 190,000 BTU heating capacity
- 8.1 GPM maximum flow rate
- Wi-Fi app control via Tuya
- Supports 5–6 outlets simultaneously
- Heavier at 42.5 pounds
- Requires 120V AC power source
- 2-year warranty coverage
- You need hot water for 5–6 outlets
- You want remote temperature adjustments
- You have an outdoor installation space
- You require indoor installation
- You need a longer warranty period
- You prefer lower weight for mounting
Verdict: APUS 190K BTU Propane Outdoor Heater provides robust 8.1 GPM output for busy households. It fits users who need simultaneous multi-fixture hot water and smart app control.
02 Specifications side by side
| Spec | Rinnai 5.3 GPM Outdoor Propane Tankless Water Heater | Rinnai 6.1 GPM Outdoor Propane Water Heater | Rinnai RXP160iN Condensing Tankless Heater | Ranein 3.6 GPM Indoor Propane Tankless Heater | APUS 80,000 BTU Indoor Propane Tankless Heater | MIZUDO 180K BTU Propane Tankless Heater | APUS 8.1 GPM Propane Outdoor Heater |
|---|---|---|---|---|---|---|---|
| Fuel Type | Propane | Propane | Natural Gas, Propane | Propane Gas | Propane | Propane | Propane |
| Max Flow Rate | 5.3 GPM | 6.1 GPM | 9 GPM | 3.6 GPM | 3.6 GPM | 8.1 GPM | 8.1 GPM |
| Heating Capacity | – | 160k BTU | 160k BTU | 80,000 BTU | 80,000 BTU | 180,000 BTU | 190,000 BTU |
| Installation Location | Outdoor | Outdoor | Indoor, Outdoor | Indoor | Indoor | Outdoor | Outdoor |
| Voltage | – | – | – | – | 120 V AC | 120V | 120V AC |
| Fixture Capacity | multiple appliances | 5 fixtures at once | 6 fixtures | 2-3 water points | 2–3 Points | 3–5 outlets | 5–6 outlets |
| Temperature Range | – | – | – | 95°F-149°F | 95–149°F | Up to 167°F | 95–149°F |
| Installation Type | – | – | – | – | – | Whole House | – |
| Features | Tankless | Tankless | Tankless, Booster Pump | Tankless | Tankless | Tankless | Tankless |
| Form Factor | Compact | Compact | – | Compact | Compact | – | – |
| Intended Use | – | – | – | Home | – | – | – |
| Dimensions | 13 × 13 × 30 inches | 10.8 × 14.1 × 24.6 inches | 19 × 19 × 31 inches | 13.8 × 13.8 × 21.7 inches | 19.3 × 19.3 × 27.6 inches | 17.1 × 17.1 × 26.2 inches | 6.54 × 6.54 × 22.5 inches |
| Weight | 33 pounds | 49.2 pounds | 57 pounds | 18 pounds | 19.2 pounds | – | 42.5 pounds |
| Size | 5.3 GPM | 6.6 GPM | 9 GPM | 3.6 GPM Indoor | – | Propane Gas, 8.1 GPM, 180,000 BTU, Indoor | – |
| Color | V53DeP – Propane/5.3 GPM | Silver | Silver | Gray-LPG | Space Gray | White 8.1LP | Gray |
| Model | V53DeP | REU-VE2125WD-US-P | RXP160iN | RH8K-LPG-FC-RATING | AP-AWH-Q10LPG | HS180A0W-LP | AP-AWH-W26LPG |
03 Frequently asked questions
Can I install these propane tankless heaters indoors?
Some models are designed for indoor use, while others are strictly for outdoor installation. The Ranein 3.6 GPM and APUS 80,000 BTU units are specified for indoor settings. In contrast, the Rinnai 5.3 GPM, Rinnai 6.1 GPM, and MIZUDO 180K BTU models are built for outdoor environments. Always verify the installation location in the product specifications before purchasing.
Which unit offers the highest hot water flow rate?
The MIZUDO 180K BTU and APUS 8.1 GPM models provide the highest flow rates at 8.1 GPM. This capacity suits large households with multiple simultaneous water demands. The Rinnai RXP160iN follows with 9 GPM, though it is a condensing unit. The original Rinnai 5.3 GPM model offers a lower output of 5.3 GPM, which is sufficient for smaller setups.
Do any of these alternatives include smart app control?
Yes, the APUS 8.1 GPM Propane Outdoor Heater features smart app control. This allows you to monitor and adjust settings remotely. Other models in this list, such as the Rinnai and MIZUDO units, do not explicitly list app connectivity in their specifications. If remote management is a priority, the APUS model is the clear choice among these options.
What are the physical dimensions of the compact models?
The Rinnai 5.3 GPM measures 13 inches wide by 30 inches high. The Ranein 3.6 GPM is slightly wider at 13.8 inches and shorter at 21.7 inches high. The APUS 80,000 BTU unit is wider at 19.3 inches but shares a similar height to the Rinnai 6.1 GPM, which is 24.6 inches high. Check these dimensions to ensure the unit fits your available space.
Are there options with booster pumps for better pressure?
The Rinnai RXP160iN Condensing Tankless Heater includes a booster pump. This feature helps maintain consistent water pressure and temperature, especially in larger homes. Most other listed models, including the standard Rinnai and APUS units, do not list a booster pump in their attributes. If you have low water pressure issues, the RXP160iN is the only specified option with this capability.
Which heater is best for supporting five simultaneous fixtures?
The Rinnai 6.1 GPM Outdoor Propane Water Heater is best suited for five simultaneous fixtures. Its 6.6 GPM flow rate ensures steady hot water for multiple outlets. The APUS 8.1 GPM and MIZUDO 180K BTU models also handle high demand effectively. The original Rinnai 5.3 GPM model supports multiple appliances but with slightly less volume than the higher-capacity alternatives.
How heavy are the outdoor propane units?
Weight varies significantly among the models. The Rinnai 5.3 GPM unit weighs 33 pounds, while the Rinnai 6.1 GPM model is heavier at 49.2 pounds. The APUS 8.1 GPM Outdoor Heater weighs 42.5 pounds. The Rinnai RXP160iN is the heaviest at 57 pounds. Ensure your mounting surface can support the specific weight of the unit you choose.
