If you want a whole-home tankless water heater near the 11 GPM mark, these three Rinnai condensing models offer high stated flow rates and different approaches to fuel choice, recirculation, and installation. The best fit depends on more than the maximum GPM: your incoming water temperature, household demand, fuel supply, venting options, and installation plan all matter.
Our top pick is the Rinnai RX199iN for its flexible indoor or outdoor installation and Smart Sense gas control. The RU199iN is a strong option if you want an indoor natural-gas unit with support for an external recirculation pump, while the RSC199iP stands out for its built-in Smart-Circ recirculation features and propane fuel.
Table of Contents
Quick Comparison
| Product | Maximum stated flow | Fuel | Standout feature |
|---|---|---|---|
| Rinnai RX199iN | Up to 11.1 GPM | Natural gas or propane | Indoor or outdoor installation; Smart Sense gas control |
| Rinnai RU199iN | Up to 11 GPM | Natural gas | Circ-Logic for pairing with an external recirculation pump |
| Rinnai RSC199iP | Up to 11 GPM | Propane | Smart-Circ learning recirculation feature |
Note: The listed GPM figures are maximum flow claims, not a promise that every home can run that flow at every temperature. A qualified installer can help determine the right size for your climate, water use, and plumbing setup.
Our Picks: Best 11 Gpm Tankless Water Heater reviews
1. Rinnai RX199iN: Best for Flexible Installation
The RX199iN is a high-capacity condensing tankless water heater with a stated maximum flow of 11.1 GPM. Its standout feature is installation flexibility: the product information says it can be installed indoors or outdoors and can run on natural gas or propane with its Smart Sense gas control system.
The compact, suitcase-size design can help save space compared with a storage tank. Rinnai also lists a Quick Flush feature to simplify flushing, along with an easy-to-use interface. For outdoor installation, the RX-OVC vent cap is required, so confirm the complete setup with your installer before choosing a location.
At its maximum stated flow, this model may suit a busy household with several hot-water demands happening at once. Still, the actual flow available depends on the temperature rise your home needs and the rest of the installation. Treat the “up to” figure as a sizing reference, not a guarantee that seven fixtures will always run at full flow together.
The RX199iN is the most flexible pick here, but its Wi-Fi control requires a separate Controlr module. Professional installation is recommended. The listed residential warranty includes 15 years on the heat exchanger and five years on parts and labor when registered within 90 days of installation; the labor term defaults to one year if it is not registered in that period.
Pros:
- Highest stated flow in this group at up to 11.1 GPM
- Supports natural gas or propane with Smart Sense
- Designed for indoor or outdoor installation
- Quick Flush feature and compact design
Cons:
- Outdoor installation requires the RX-OVC vent cap
- Wi-Fi control requires a separate module
Verdict: Choose the RX199iN if you want the most installation and fuel flexibility of these three models and can plan for the required professional setup.
2. Rinnai RU199iN: Best for Natural-Gas Homes with Recirculation
The RU199iN is an indoor natural-gas tankless water heater with a stated flow rate of up to 11 GPM. Like the other models here, it uses a compact tankless design and heats water on demand rather than storing a tankful for later use.
Its Circ-Logic feature is designed to pair with an external pump for scheduled or on-demand recirculation. That setup can help reduce the wait for hot water at taps, though it requires a compatible pump and a home plumbing arrangement that supports recirculation. The pump is not described as included, so factor that into your installation plan.
This model is a straightforward choice if your home uses natural gas and you want recirculation options. Unlike the RX199iN, it is specified for indoor installation and does not list support for propane. Its maximum flow is close to the RX199iN’s, but the best choice between them comes down to fuel, installation location, and whether you value the RX’s broader flexibility.
Rinnai recommends professional installation. The listed residential warranty terms are 15 years for the heat exchanger, five years for labor, and one year for parts. Wi-Fi monitoring is available with a separate Controlr module.
Pros:
- Up to 11 GPM stated flow for whole-home use
- Circ-Logic can work with an external recirculation pump
- Compact design saves space compared with a storage tank
- Wi-Fi monitoring is available with an optional module
Cons:
- Specified for indoor natural-gas installation
- Recirculation requires an external pump
Verdict: The RU199iN is a good match for a natural-gas home that needs a high-capacity indoor unit and plans to use a compatible external recirculation pump.
3. Rinnai RSC199iP: Best for Smart Recirculation on Propane
The RSC199iP is an indoor condensing tankless water heater that uses propane and has a stated flow rate of up to 11 GPM. Its main distinction is Smart-Circ, which is designed to learn hot-water usage patterns and schedule recirculation accordingly.
That feature may appeal if you want recirculation built into your hot-water plan rather than choosing a model whose recirculation feature pairs with an external pump. How useful it is depends on your household routine and plumbing layout. Rinnai lists multiple venting options, which may help the unit fit different indoor installation spaces.
The RSC199iP’s propane fuel makes it a natural candidate for homes set up for propane, but it is not the listed choice for a natural-gas installation. Its stated maximum flow is similar to the RU199iN, so the deciding factors are fuel type and the Smart-Circ feature rather than a large difference in advertised capacity. Wi-Fi control requires a separate Controlr module.
Rinnai recommends professional installation. The listed residential warranty terms are 15 years for the heat exchanger, five years for labor, and one year for parts.
Pros:
- Up to 11 GPM stated flow
- Smart-Circ learns usage patterns to schedule recirculation
- Designed for propane-powered homes
- Multiple venting options are listed
Cons:
- Specified for indoor installation
- Wi-Fi control requires a separate module
Verdict: Choose the RSC199iP if your home uses propane and you want Smart-Circ recirculation features in a high-capacity indoor tankless heater.
How to Choose an 11 GPM Tankless Water Heater
Match the heater to your actual hot-water demand
Think about how many hot-water uses may overlap in your home, such as showers, laundry, and a kitchen tap. A heater’s maximum GPM is only part of the picture. The hotter the water needs to be raised from its incoming temperature, the more carefully you need to check the heater’s usable flow. Ask an installer to size the unit for your region and likely peak use rather than relying on the headline GPM alone.
Confirm the fuel type
Choose a model that matches your home’s fuel supply. The RX199iN is described as supporting natural gas or propane with Smart Sense. The RU199iN is specified for natural gas, while the RSC199iP is a propane model. Do not assume that a gas appliance can be converted or connected to a different fuel without manufacturer approval and qualified installation.
Plan the installation location and venting
The RX199iN is listed for indoor or outdoor installation, with an RX-OVC vent cap required for outdoor use. The RU199iN and RSC199iP are listed as indoor models. Before you buy, have a qualified installer check the location, venting path, clearances, and other site needs. A model that looks compact on paper still has to work with your home’s layout and local requirements.
Decide whether recirculation is worth it
Recirculation can reduce the wait for hot water at a tap, but the right setup depends on your plumbing and how you use hot water. The RU199iN’s Circ-Logic is designed to pair with an external pump. The RSC199iP’s Smart-Circ feature learns usage patterns and schedules recirculation. The RX199iN’s listed features focus on installation flexibility and flushing rather than a built-in learning recirculation feature.
Check what is included and what is optional
Some features may require extra equipment. For example, the product information says Wi-Fi control or monitoring uses a separate Controlr module on these models. The RU199iN’s recirculation function requires an external pump, and outdoor installation of the RX199iN requires its specified vent cap. Confirm included components, compatible accessories, and installation costs before making a final choice.
Review warranty terms and registration needs
Warranty coverage differs by model and component. Read the current product documentation and confirm the exact terms before purchase. For the RX199iN, the supplied product information states that registration within 90 days of installation is required for its listed five-year labor coverage; otherwise, labor coverage defaults to one year. Keep installation and registration records with your appliance paperwork.
Use a qualified installer
Rinnai recommends professional installation for these heaters. A qualified technician can check fuel supply, sizing, venting, condensate handling, and compatibility with your plumbing. Getting those details right is especially important for a high-capacity gas appliance and can help you avoid choosing a model that does not fit your home.
Frequently Asked Questions
Is an 11 GPM tankless water heater enough for a whole home?
It can be suitable for many whole-home setups, but the number of fixtures it can serve at once depends on the required temperature rise and each fixture’s flow. Have your home’s peak demand and incoming water temperature checked before selecting a model.
Does “up to 11 GPM” mean I will always get 11 GPM?
No. “Up to” describes a maximum under the right conditions. The flow available in your home can be lower when the heater must raise cold incoming water to a higher temperature or when several fixtures draw hot water at the same time.
Which of these models supports both natural gas and propane?
The RX199iN is described as supporting both fuel types through its Smart Sense gas control system. The RU199iN is specified for natural gas, and the RSC199iP is a propane model. Confirm fuel compatibility with an installer before purchase.
Which model has Smart-Circ?
The Rinnai RSC199iP has Smart-Circ, which is designed to learn usage patterns and schedule recirculation. The RU199iN instead has Circ-Logic for pairing with an external pump.
Can I install one of these heaters myself?
Rinnai recommends professional installation. A qualified installer can check the required fuel, venting, sizing, and plumbing details for your home.
Do these models include Wi-Fi control?
The supplied product information says Wi-Fi control or monitoring is available with a separate Controlr module. Check the product listing and installation documentation to confirm what is included.
What is the best pick for a home without natural gas?
If your home uses propane, the RX199iN and RSC199iP are the relevant options in this group. The RX199iN is described as supporting either natural gas or propane, while the RSC199iP is a propane model with Smart-Circ. Have an installer confirm the best fit for your setup.
Final Recommendation
The Rinnai RX199iN is the strongest all-around choice in this group if you want the highest stated flow and the flexibility to use natural gas or propane, with indoor or outdoor installation options. Choose the RU199iN for an indoor natural-gas setup that will use an external recirculation pump, or the RSC199iP if you have propane and want Smart-Circ. Before buying, confirm the required flow, fuel, and installation details with a qualified professional.
