Takagi T-H3M Outdoor Natural Gas vs Takagi 6.6 GPM Propane Outdoor: Spec Comparison
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You are comparing the takagi t h3m outdoor natural gas vs 6 6 gpm propane outdoor models from Takagi. Both units are condensing tankless water heaters designed for outdoor installation. They share a white finish and compact footprint. The main difference lies in their fuel source. One runs on natural gas, while the other uses propane. This choice affects your gas line requirements and local compatibility. Understanding these specs helps you pick the right unit for your home.
Key differences
| Aspect | Takagi T-H3M Outdoor Natural Gas Heater | Takagi 6.6 GPM Propane Outdoor Heater |
|---|---|---|
| Fuel Type | Natural Gas | Propane |
| Flow Rate | not listed | 6.6 GPM |
| Dimensions | 29.5 x 13.1 x 17.8 inches | 24.9 x 17.8 x 11.3 inches |
| Weight | 44 pounds | 52 pounds |
| Capacity | not listed | 4.0 Gallons |
Which one should you choose?
Choose Takagi T-H3M Outdoor Natural Gas Heater if
- You have a natural gas supply line installed outdoors.
- You need a unit that weighs less for easier mounting.
- You prefer a taller, narrower footprint for your wall space.
Choose Takagi 6.6 GPM Propane Outdoor Heater if
- You have a propane tank or supply line available.
- You need a known flow rate of 6.6 GPM.
- You want a unit with listed internal capacity details.
Verdict: Choose the natural gas model if your home already has a gas line and you prioritize a lighter weight. Pick the propane model if you need a specified flow rate of 6.6 GPM and have propane available. Both are efficient outdoor options that meet emission standards.
Spec Comparison: Natural Gas vs Propane
Fuel Type
Your first choice involves the fuel source. The Takagi T-H3M Outdoor Natural Gas Heater runs on natural gas, which is typically supplied via a fixed underground line to your home. This means you generally do not need to manage fuel tanks or schedule deliveries. In contrast, the Takagi 6.6 GPM Propane Outdoor Heater uses propane. Propane is stored in external tanks that you must monitor and refill. If your property already has a natural gas line, the T-H3M model offers a more convenient, continuous fuel supply without the logistical steps required for propane tank management.
Flow Rate
Flow rate determines how much hot water you can draw simultaneously. The Takagi 6.6 GPM Propane Outdoor Heater is explicitly rated for 6.6 gallons per minute. This higher capacity supports multiple showers or appliances running at once in larger households. The Takagi T-H3M Outdoor Natural Gas Heater does not list a specific flow rate in its provided specifications. Without this data, you cannot confirm if it matches the propane model’s output. If high simultaneous flow is critical for your home, the propane unit’s stated 6.6 GPM provides a clear, measurable advantage over the unspecified rate of the natural gas unit.
Dimensions
Physical size affects where you can mount the unit. The Takagi T-H3M Outdoor Natural Gas Heater measures 29.5 inches in height, 13.1 inches in width, and 17.8 inches in length. It is taller and narrower. The Takagi 6.6 GPM Propane Outdoor Heater is shorter at 24.9 inches high, but wider at 17.8 inches and deeper at 11.3 inches. The propane model has a more compact vertical profile, which may fit better under eaves or in tight vertical spaces. The natural gas model requires more height clearance but less horizontal width. Your available mounting space will determine which footprint works best.
Weight
Weight impacts the structural support needed for installation. The Takagi T-H3M Outdoor Natural Gas Heater weighs 44 pounds according to its specs, though one feature list notes 52.0 lb. The Takagi 6.6 GPM Propane Outdoor Heater weighs 52 pounds. Both units are relatively lightweight for tankless heaters, but the propane model is consistently listed at the heavier end of the range. You must ensure your mounting bracket and wall can support the load. The natural gas unit may be slightly lighter if the 44-pound spec is accurate, reducing stress on your mounting hardware compared to the heavier propane version.
Venting Type
Both units use condensing venting technology. This method extracts heat from exhaust gases more efficiently than standard venting, improving overall energy efficiency. Condensing systems often allow for flexible venting options, including horizontal termination through a wall, which is ideal for outdoor installations. Since both the Takagi T-H3M and the Takagi 6.6 GPM models share this venting type, neither holds an advantage here. You will need to follow similar installation protocols for vent termination for both, ensuring proper clearance and exhaust routing as specified in their respective manuals.
Which tankless heater fits your home
Users with existing natural gas lines
This unit runs on natural gas, connecting directly to your home's fixed underground supply. You avoid the hassle of propane tank refills. It is a condensing model built for outdoor placement. The white finish matches standard exterior aesthetics. This choice simplifies your fuel logistics by using the utility line you already have installed.
Buyers needing high flow rate
This model delivers a 6.6 GPM flow rate, supporting multiple simultaneous uses. It runs on propane, requiring a separate tank supply. The unit features computerized safety controls and no pilot light. It meets ultra-low NOx emission standards. The compact dimensions fit tight outdoor spaces. Choose this if hot water volume is your priority.
Those prioritizing compact dimensions
This heater measures 11.3 inches in length and 17.8 inches in width. It is shorter in height than the natural gas alternative. The condensing design allows for flexible venting options. It operates on propane fuel. The white casing resists weathering. Select this model if your outdoor installation space is limited in width or depth.
The products compared
Takagi T-H3M Outdoor Natural Gas Heater
Best for: outdoor natural gas installations
- 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 outdoor tankless water heater runs on natural gas and uses condensing technology for efficiency. It measures 29.5 inches high and weighs 44 pounds. The compact footprint fits tight exterior spaces. It suits homes with existing natural gas lines. You get reliable hot water without a storage tank. The unit is built in Japan for durability.
Pros
- Condensing technology for high efficiency
- Compact 13.1-inch width
- Designed for outdoor installation
- Natural gas fuel type
Cons
- Limited to natural gas only
- Heavier than propane models
- Requires outdoor mounting space
Good fit if
- You have natural gas available
- You need an outdoor unit
- You want compact dimensions
Skip if
- You use propane fuel
- You need indoor installation
- You require a storage tank
Verdict: Takagi T-H3M Outdoor Natural Gas fits homes with natural gas lines. It offers efficient condensing performance in a small outdoor package.
Takagi 6.6 GPM Propane Outdoor Heater
Best for: High flow propane outdoor installations
- 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
This is a condensing outdoor tankless water heater running on propane. It delivers 6.6 gallons per minute of hot water. The unit measures 24.9 by 17.8 by 11.3 inches and weighs 52 pounds. It meets ultra-low NOx emission standards. You get endless hot water with computerized safety features and no pilot light. It fits outdoor spaces where propane is available.
Pros
- 6.6 GPM flow rate for steady hot water
- Condensing technology for high efficiency
- Meets 2012 SCAQMD Rule 1146.2 for low emissions
- No pilot light reduces standby energy loss
Cons
- Requires propane fuel, not natural gas
- Outdoor installation only
- 4.0 gallon storage capacity is limited
Good fit if
- You need high flow for multiple fixtures
- You have a propane supply line
- You want an outdoor condensing unit
Skip if
- You only have natural gas access
- You need indoor installation
- You require a larger storage tank
Verdict: Takagi 6.6 GPM Propane Outdoor Heater delivers strong flow for homes with propane. It suits outdoor setups needing high efficiency and low emissions. Choose it if you prioritize propane fuel and high GPM output.
Specifications side by side
| Spec | Takagi T-H3M Outdoor Natural Gas Heater | Takagi 6.6 GPM Propane Outdoor Heater |
|---|---|---|
| Fuel Type | Natural Gas | Propane |
| Flow Rate | not stated | 6.6 GPM |
| Installation Location | Outdoor | Outdoor |
| Dimensions | 29.5 x 13.1 x 17.8 inches | 24.9 x 17.8 x 11.3 in |
| Venting Type | Condensing | Condensing |
| Capacity | not stated | 4.0 Gallons |
| Weight | 44 pounds | 52 pounds |
| Color | White | White |
| Model | TH3MOSNG | T-H3J-OS-P |
| Size | not stated | Medium |
Frequently asked questions
Are both Takagi models condensing heaters?
Yes, both units are condensing tankless water heaters. This venting type allows for high efficiency by capturing heat from exhaust gases. You can install them outdoors since they are designed for outdoor placement. The condensing technology helps reduce emissions while heating water.
Which model is smaller in size?
The Takagi T-H3M Outdoor Natural Gas Heater is more compact. It measures 13.1 inches wide, 17.8 inches long, and 29.5 inches tall. In contrast, the propane model is wider at 17.8 inches but shorter at 24.9 inches. Choose the natural gas unit if you need a narrower footprint.
Does the propane model have a water capacity rating?
Yes, the Takagi 6.6 GPM Propane Outdoor Heater lists a capacity of 4.0 gallons. This specification is unique to this model in the provided data. The natural gas model does not list a specific water capacity in its attributes. This detail may help you understand internal volume.
How much does each heater weigh?
The Takagi T-H3M Outdoor Natural Gas Heater weighs 44 pounds. The Takagi 6.6 GPM Propane Outdoor Heater is heavier at 52 pounds. Both units are relatively light for outdoor installation. Ensure your mounting surface can support the specific weight of your chosen fuel type.
Can I install these units in any outdoor location?
Both models are designed specifically for outdoor installation. You do not need to enclose them in a basement or utility room. Their outdoor design protects internal components from weather while allowing easy access for maintenance. Just ensure the location meets local venting and clearance codes.
What color are these water heaters?
Both the natural gas and propane models feature a white finish. This color helps them blend with exterior walls or siding. The consistent aesthetic allows for a clean look regardless of which fuel source you select. The white coating also aids in reflecting sunlight.