Takagi Outdoor Propane Tankless Water Heater Alternatives: 6 Similar Picks Compared
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The Takagi T-H3S-OS-P delivers 8 GPM of hot water using propane in an outdoor condensing design. It meets strict emission rules and saves space. If you need takagi outdoor propane tankless water heater alternatives, you may want different specs. Some buyers prefer natural gas. Others need higher flow rates or smaller footprints. You might also want WiFi control or a different venting type.
This list compares 6 similar picks. We chose these units because their published specifications overlap with the original model. You will see options in propane and natural gas. Some offer higher flow rates, while others prioritize compact size. All units are designed for outdoor installation. We explain what each spec means for your daily use. This helps you choose the right unit for your home without guessing.
How the Alternatives Compare
Takagi Outdoor 8 GPM Natural Gas Water Heater
The Takagi T-H3S-OS-N matches the original 8 GPM flow rate but switches from propane to natural gas. It uses the same condensing venting technology and identical dimensions, making it a direct swap for homes with gas lines. You get the same strict emission compliance and space-saving design. This model is ideal if you have natural gas available and want the same performance without changing your installation footprint. The only difference is the fuel source, which may affect operating costs and availability depending on your utility setup.
Takagi 6.6 GPM Propane Outdoor Heater
The Takagi T-H3J-OS-P offers a lower 6.6 GPM flow rate compared to the original 8 GPM. It retains the propane fuel type and condensing venting for high efficiency and low emissions. The unit is slightly lighter at 52 pounds but shares the same compact dimensions. This model suits households with moderate hot water needs where maximum flow is less critical. You trade some capacity for a potentially lower upfront cost and reduced gas consumption. It remains a strong choice for outdoor propane setups that prioritize efficiency and emission standards over high-volume usage.
Rinnai RE180eP Outdoor Propane Water Heater
The Rinnai RE180eP provides a lower 5.0 GPM flow rate and uses non-condensing venting instead of the original's condensing design. It is significantly more compact, measuring 14.1 inches wide and weighing only 50 pounds. This model suits small outdoor spaces or single-bathroom setups where space is tight. You give up some flow rate and high-efficiency condensing technology for a smaller footprint. It is a practical choice for buyers who prioritize physical size and ease of installation over maximum hot water output and strict emission compliance.
Rheem RTG 9.5 GPM Outdoor Propane Tankless Water Heater
The Rheem RTG-95XELP delivers a higher 9.5 GPM flow rate, outperforming the original 8 GPM unit. It uses non-condensing venting and includes WiFi connectivity for smart control. The unit is lighter at 40.5 pounds and slightly narrower. This model fits busy households needing high-volume hot water simultaneously. You gain capacity and smart features but sacrifice the high efficiency and strict emission compliance of the condensing original. It is best for users who prioritize flow rate and modern connectivity over energy conservation and ultra-low nitrogen oxide emissions.
Rinnai 9 GPM Outdoor Propane Condensing Heater
The Rinnai RUR160EP offers a higher 9 GPM flow rate with condensing venting, similar to the original. It is taller at 33.9 inches and heavier at 80.9 pounds. This model suits homes needing recirculation features and higher output. You gain more hot water capacity and efficient venting but require more vertical space. The larger size may complicate installation in tight areas. It is a solid choice for households with higher hot water demands who still value condensing efficiency and emission standards, provided they have the space for a larger unit.
Takagi T-H3M Outdoor Natural Gas Heater
The Takagi T-H3M-OS-N switches from propane to natural gas while maintaining condensing venting for high efficiency. It has a smaller footprint, measuring 13.1 inches wide, and weighs only 44 pounds. This model suits outdoor natural gas installations with tight space constraints. You gain a more compact design and lower weight but may see reduced flow rates compared to the original. It is ideal for single-bathroom setups or homes with limited outdoor space. The switch to natural gas requires a compatible gas line, making it a specific choice for those with existing natural gas infrastructure.
Quick picks
Our 7 picks
Takagi Outdoor Propane Tankless Water Heater
Best for: outdoor propane use with strict emission rules
- Fuel Type
- Propane
- Flow Rate
- 8 GPM
- Installation Location
- Outdoor
- Dimensions
- 24.9 x 17.8 x 11.3 in
- Venting Type
- Condensing
- Capacity
- 8 Gallon
View on Amazon: Takagi Outdoor Propane Tankless Water Heater Affiliate link
This Takagi unit delivers 8 GPM of hot water using propane. Its condensing design captures heat from exhaust gases, boosting efficiency. The compact shell measures 24.9 by 17.8 by 11.3 inches. It meets strict SCAQMD Rule 1146.2 for ultra-low NOx emissions. You get endless hot water without a standing pilot light. This model suits outdoor installations where space and emissions matter.
Pros
- 8 GPM flow rate for strong hot water output
- Condensing technology for high energy efficiency
- Meets SCAQMD Rule 1146.2 ultra-low NOx standards
- No standing pilot light reduces idle energy use
Cons
- Lower 8 GPM capacity compared to 9.5 GPM competitors
- Heavier at 69 pounds than non-condensing alternatives
- Requires specific propane venting setup for condensing model
Good fit if
- You need an outdoor propane heater with ultra-low emissions
- You want a condensing model for maximum efficiency
- You have space for a 69-pound outdoor unit
Skip if
- You require more than 8 GPM for multiple showers
- You prefer a lighter, non-condensing propane unit
- You need a natural gas model instead of propane
Verdict: Takagi T-H3S-OS-P 8 GPM Propane Outdoor Heater fits homes needing strict emission compliance and high efficiency. It serves you well if you prioritize condensing technology over maximum flow rate.
Takagi Outdoor 8 GPM Natural Gas Water Heater
Best for: Natural gas outdoor installations needing clean emissions
- Fuel Type
- Natural Gas
- Flow Rate
- 8 GPM
- Installation Location
- Outdoor
- Dimensions
- 24.9 x 17.8 x 11.3 inches
- Venting Type
- Condensing
- Capacity
- 8 Gallon
View on Amazon: Takagi Outdoor 8 GPM Natural Gas Water Heater Affiliate link
This Takagi outdoor tankless heater runs on natural gas and delivers 8 GPM of hot water. Its condensing design offers high efficiency and meets Ultra-Low NOx emission standards. The compact unit measures 24.9 by 17.8 by 11.3 inches. It features computerized safety controls and operates without a pilot light. This model suits outdoor installations where space is limited and clean emissions are required.
Pros
- 8 GPM flow rate for steady hot water supply
- Condensing technology ensures high energy efficiency
- Meets Ultra-Low NOx emission standards for clean operation
- Compact outdoor footprint saves space
Cons
- Requires natural gas fuel, not propane
- Smaller flow rate than 9.5 GPM competitors
- Condensing venting may need specific installation clearance
Good fit if
- You have natural gas available outdoors
- You need Ultra-Low NOx emissions compliance
- You prefer a compact outdoor unit
Skip if
- You only have propane fuel lines
- You need more than 8 GPM flow
- You require indoor installation options
Verdict: Takagi T-H3S-OS-N 8 GPM Natural Gas Outdoor Unit delivers efficient, eco-friendly hot water for natural gas homes. It fits well where strict emission rules apply and space is tight.
Takagi 6.6 GPM Propane Outdoor Heater
Best for: outdoor propane homes with emission limits
- Fuel Type
- Propane
- Flow Rate
- 6.6 GPM
- Installation Location
- Outdoor
- Dimensions
- 24.9 x 17.8 x 11.3 in
- Venting Type
- Condensing
- Capacity
- 4.0 Gallons
View on Amazon: Takagi 6.6 GPM Propane Outdoor Heater Affiliate link
The Takagi T-H3J-OS-P is a condensing propane water heater built for outdoor use. It delivers 6.6 GPM of hot water with ultra-low NOx emissions. Its compact 24.9 x 17.8 x 11.3-inch frame saves space. This unit suits homes needing reliable on-demand heating without a pilot light. It fits well in areas with strict emission rules.
Pros
- 6.6 GPM flow rate for steady hot water
- Condensing design for high efficiency
- Meets 2012 SCAQMD Rule 1146.2 for low NOx
- No pilot light reduces standby loss
Cons
- Lower flow rate than 9.5 GPM competitors
- Heavier at 52 pounds than some units
- Smaller 4.0-gallon capacity than larger models
Good fit if
- You need a propane heater for outdoor installation
- You live in an area with strict emission rules
- You want a compact unit with no pilot light
Skip if
- You need more than 6.6 GPM for multiple showers
- You require a natural gas connection instead of propane
- You want a lighter unit for easier mounting
Verdict: Takagi T-H3J-OS-P Outdoor Propane Heater is a solid choice for outdoor propane setups requiring low emissions. It fits homes that prioritize efficiency and compact size over high flow rates.
Rinnai RE180eP Outdoor Propane Water Heater
Best for: small outdoor spaces with moderate demand
- Fuel Type
- Propane
- Flow Rate
- 8.5 GPM
- Installation Location
- Outdoor
- Dimensions
- 24.6 x 14.1 x 10.8 inches
- Venting Type
- Non-Condensing
- Weight
- 50 pounds
View on Amazon: Rinnai RE180eP Outdoor Propane Water Heater Affiliate link
The Rinnai RE180eP is a non-condensing propane unit designed for outdoor installation. It delivers 6.9 GPM of hot water, supporting up to five fixtures simultaneously. Its compact footprint measures 24.6 by 14.1 by 10.8 inches and weighs 50 pounds. The LED screen displays error codes and service reminders. You should consider this model if you need a reliable, space-saving solution for moderate hot water demands.
Pros
- Provides 6.9 GPM flow rate for multiple simultaneous uses
- Compact outdoor design fits in small spaces
- LED screen shows error codes and service reminders
- Includes 15-year heat exchanger warranty
Cons
- Lower flow rate than most competitors on this list
- WiFi control module sold separately
- Labor warranty drops to 1 year if not registered within 90 days
Good fit if
- You need a compact outdoor unit for propane
- You have moderate hot water demands
- You want a durable heat exchanger warranty
Skip if
- You need more than 6.9 GPM
- You want built-in WiFi connectivity
- You require a condensing model for higher efficiency
Verdict: Rinnai RE180eP Outdoor Propane suits buyers who prioritize compact size and warranty coverage over maximum flow rate. It is a solid choice for small households with moderate hot water needs.
Rheem RTG 9.5 GPM Outdoor Propane Tankless Water Heater
Best for: High-flow outdoor propane needs
- Fuel Type
- Liquid Propane
- Flow Rate
- 9.5 GPM
- BTU
- 199,900 BTU/hr
- Installation Location
- Outdoor
- Temperature Control
- ±1°F
- Certification
- CSA
View on Amazon: Rheem RTG 9.5 GPM Outdoor Propane Tankless Water Heater Affiliate link
This outdoor propane unit delivers 9.5 GPM at a 35°F rise, powered by 199,900 BTUs. It features a non-condensing design with a 0.82 UEF. You get WiFi control and ±1°F digital temperature precision. The compact 9.4-inch depth fits tight spaces. It suits homes needing high flow for multiple showers without condensing complexity.
Pros
- 9.5 GPM flow rate for whole-house use
- WiFi enabled for remote monitoring
- ±1°F digital temperature precision
- Non-condensing outdoor design
Cons
- Lower 0.82 UEF than condensing competitors
- Heavier 40.5 lb build
- Outdoor installation only
Good fit if
- You need high flow for 3-4 simultaneous showers
- You prefer non-condensing outdoor installation
- You want WiFi temperature control
Skip if
- You require condensing high efficiency
- You need indoor installation
- You want a lighter unit
Verdict: Rheem RTG-95XELP 9.5 GPM Propane delivers strong flow and smart control for outdoor setups. It fits busy households prioritizing capacity over maximum efficiency.
Rinnai 9 GPM Outdoor Propane Condensing Heater
Best for: outdoor propane homes needing recirculation
- Fuel Type
- Propane
- Flow Rate
- 9 GPM
- Installation Location
- Outdoor
- Dimensions
- 33.9 x 14.8 x 22.1 inches
- Venting Type
- Condensing
- Weight
- 80.9 pounds
View on Amazon: Rinnai 9 GPM Outdoor Propane Condensing Heater Affiliate link
The Rinnai RUR160EP is a condensing propane tankless water heater designed for outdoor installation. It delivers 9 GPM of hot water using ThermaCirc360 technology, which includes a built-in recirculation pump and thermal bypass valve for faster heating without a dedicated return line. The unit measures 33.9 x 14.8 x 22.1 inches and weighs 80.9 pounds. It offers a 15-year heat exchanger warranty and includes WiFi monitoring capabilities for remote management.
Pros
- 9 GPM flow rate for consistent hot water
- Built-in recirculation pump and thermal bypass valve
- WiFi monitoring for remote control
- 15-year residential heat exchanger warranty
Cons
- Model is discontinued; replaced by RSC160eP
- Non-condensing competitors offer simpler maintenance profiles
- Heavier at 80.9 pounds than some alternatives
Good fit if
- You need a high-flow propane unit for outdoor use
- You want built-in recirculation without a return line
- You prefer condensing efficiency for fuel savings
Skip if
- You need a currently manufactured model
- You require a natural gas fuel type
- You want a non-condensing installation
Verdict: Rinnai RUR160EP 9 GPM Propane Outdoor provides reliable high-flow performance with smart monitoring, though its discontinued status may complicate long-term support for some buyers.
Takagi T-H3M Outdoor Natural Gas Heater
Best for: tight outdoor spaces with natural gas
- Fuel Type
- Natural Gas
- Installation Location
- Outdoor
- Dimensions
- 29.5 x 13.1 x 17.8 inches
- Venting Type
- Condensing
- Weight
- 44 pounds
View on Amazon: Takagi T-H3M Outdoor Natural Gas Heater Affiliate link
This Takagi unit is a condensing outdoor water heater designed for natural gas. It measures 29.5 by 13.1 by 17.8 inches and weighs 44 pounds. The compact footprint suits tight exterior spaces. You get reliable hot water without the bulk of larger models. It fits well in areas where space is limited but you need steady performance.
Pros
- Condensing technology for efficiency
- Compact outdoor design
- Natural gas fuel type
- Lightweight at 44 pounds
Cons
- Natural gas only, not propane
- No included flow rate spec
- Single gas compatibility limits use
Good fit if
- You have natural gas available
- You need an outdoor unit
- You have limited wall space
Skip if
- You only have propane lines
- You need indoor installation
- You require high flow rates
Verdict: Takagi T-H3M-OS-N Natural Gas Outdoor Heater suits homeowners with natural gas lines who need a small outdoor unit. It works best for single-bathroom setups where space is tight.
Specifications side by side
| Spec | Takagi Outdoor Propane Tankless Water Heater | Takagi Outdoor 8 GPM Natural Gas Water Heater | Takagi 6.6 GPM Propane Outdoor Heater | Rinnai RE180eP Outdoor Propane Water Heater | Rheem RTG 9.5 GPM Outdoor Propane Tankless Water Heater | Rinnai 9 GPM Outdoor Propane Condensing Heater | Takagi T-H3M Outdoor Natural Gas Heater |
|---|---|---|---|---|---|---|---|
| Fuel Type | Propane | Natural Gas | Propane | Propane | Liquid Propane | Propane | Natural Gas |
| Flow Rate | 8 GPM | 8 GPM | 6.6 GPM | 8.5 GPM | 9.5 GPM | 9 GPM | not stated |
| BTU | not stated | not stated | not stated | not stated | 199,900 BTU/hr | not stated | not stated |
| Installation Location | Outdoor | Outdoor | Outdoor | Outdoor | Outdoor | Outdoor | Outdoor |
| Temperature Control | not stated | not stated | not stated | not stated | ±1°F | not stated | not stated |
| Certification | not stated | not stated | not stated | not stated | CSA | not stated | not stated |
| Dimensions | 24.9 x 17.8 x 11.3 in | 24.9 x 17.8 x 11.3 inches | 24.9 x 17.8 x 11.3 in | 24.6 x 14.1 x 10.8 inches | 20.8 x 13.5 x 9.4 inches | 33.9 x 14.8 x 22.1 inches | 29.5 x 13.1 x 17.8 inches |
| Venting Type | Condensing | Condensing | Condensing | Non-Condensing | Non-Condensing | Condensing | Condensing |
| Capacity | 8 Gallon | 8 Gallon | 4.0 Gallons | not stated | not stated | not stated | not stated |
| Features | not stated | not stated | not stated | not stated | WiFi | not stated | not stated |
| Weight | 69 pounds | not stated | 52 pounds | 50 pounds | 40.5 pounds | 80.9 pounds | 44 pounds |
| Size | Medium | Medium | Medium | 8.5 GPM | 9.5 GPM (WiFi) | 9 GPM | not stated |
| Color | No Finish | White | White | Silver | Gray | Outdoor Installation | White |
| Model | T-H3S-OS-P | T-H3S-OS-N | T-H3J-OS-P | REU-VE2432WD-US-P | RTG-95XELP-3 | RUR160ep | TH3MOSNG |
You can evaluate overall performance specs by comparing these models against the best propane tankless water heaters available.
Frequently asked questions
Can I use a natural gas outdoor heater instead of propane?
Yes, several models support natural gas. The Takagi T-H3S-OS-N delivers 8 GPM with condensing venting, matching the propane version’s output. The Takagi T-H3M-OS-N offers a smaller footprint for tight spaces. Both units maintain high efficiency while switching fuel sources, provided your home has the correct gas line infrastructure.
Which outdoor tankless heater has the highest flow rate?
The Rheem RTG-95XELP-3 provides 9.5 GPM, the highest in this list. It uses non-condensing venting and includes WiFi connectivity for remote control. This model suits busy households needing strong capacity. It is lighter and more compact than many high-flow competitors, weighing only 40.5 pounds.
Do I need condensing venting for outdoor propane installations?
Condensing venting is ideal for strict emission rules and higher efficiency. The Takagi T-H3S-OS-P and T-H3J-OS-P use this technology for propane. However, the Rinnai RE180eP and Rheem RTG-95XELP use non-condensing designs. Choose condensing units if eco-friendliness is your priority, or non-condensing for simpler venting setups.
What is the smallest outdoor tankless water heater available?
The Rheem RTG-95XELP-3 is the most compact option. It measures 13.5 inches wide, 20.8 inches high, and 9.4 inches long. Despite its small size, it delivers 9.5 GPM. The Rinnai RE180eP is also narrow at 14.1 inches wide, making it suitable for small outdoor spaces.
Are there outdoor heaters with smart control features?
Yes, the Rheem RTG-95XELP-3 includes WiFi connectivity for smart control. This allows you to monitor and adjust settings remotely. Other models in this list, such as the Takagi and Rinnai units, do not list WiFi or smart features in their specifications. Check product details if remote management is essential.
How much do these outdoor water heaters weigh?
Weights vary by model and construction. The Takagi T-H3S-OS-P weighs 69 pounds. The Rinnai RUR160ep is heavier at 80.9 pounds due to its larger size. The Rheem RTG-95XELP-3 is the lightest at 40.5 pounds. Heavier units often indicate more robust internal components or larger heat exchangers.