If you are shopping for a 200,000 BTU tankless water heater, the Rinnai RE199iN is the closest match in this list at 199,000 BTU. The APUS 190,000 BTU model is another high-output option, while the Rheem and Rinnai RX160iN offer different fuel, installation, and efficiency features. Choose based on your fuel supply, incoming water temperature, expected simultaneous use, and installation location—not BTU rating alone.
| Product | Fuel and installation | Listed capacity | Best for |
|---|---|---|---|
| Rinnai RE199iN | Natural gas, indoor | 199,000 BTU; up to 9.8 GPM | High-demand homes |
| APUS | Natural gas, outdoor | 190,000 BTU; up to 8.1 GPM | Outdoor whole-home installation |
| Rheem RTG | Propane, outdoor | 160,000 BTU; 7.0 GPM at 35°F rise | Propane homes needing outdoor mounting |
| Rinnai RX160iN | Natural gas or propane | Up to 9 GPM | Flexible fuel and installation options |
| Rinnai RE180iP | Propane, indoor | Up to 8.5 GPM | Indoor propane installations |
Rinnai RE199iN Natural Gas Tankless Water Heater
Best for: Natural-gas households seeking output closest to 200,000 BTU. This indoor, non-condensing unit is rated at 199,000 BTU and up to 9.8 GPM, making it the closest listed match to the requested capacity. Its compact wall-mounted design, LED diagnostic codes, and service reminders are useful for space-conscious installations and maintenance.
The product information lists a 15-year limited heat exchanger warranty, five years on parts, and one year on labor. Wi-Fi monitoring requires a separately sold Controlr module. Actual flow depends on temperature rise and household demand, so the maximum GPM figure should not be treated as a guarantee for every climate or setup.
APUS 190,000 BTU Outdoor Natural Gas Heater
Best for: Natural-gas homes that want a high-output outdoor unit. APUS lists 190,000 BTU and up to 8.1 GPM, with a claimed capacity for three showers and two faucets simultaneously. App control through Tuya or a wired controller provides temperature adjustment from 95°F to 149°F; the stated temperature accuracy is ±1°F.
Its outdoor design can preserve indoor space, and the listing specifies a 120V AC connection and standard 3/4-inch water and gas connections. Confirm site conditions, local code requirements, and utility capacity before purchase. The listed flow depends on operating conditions, and outdoor placement must suit the home’s climate and installation requirements.
Rheem RTG 160,000 BTU Outdoor Propane Heater
Best for: Propane households wanting an outdoor whole-home model. The Rheem is rated at 160,000 BTU and 7.0 GPM at a 35°F temperature rise. The manufacturer describes it as suitable for two to three simultaneous showers. Because it is designed for outdoor installation, it eliminates the need for indoor venting.
The listing identifies this as a non-condensing unit with a 0.82 Uniform Energy Factor and a metal cabinet for wall mounting by a qualified installer. Choose it if propane and outdoor placement fit your home; avoid it if you need an indoor unit or are specifically targeting an output close to 200,000 BTU. Its stated GPM is tied to the listed temperature rise.
Rinnai RX160iN Condensing Smart Sense Heater
Best for: Buyers who value fuel and placement flexibility. The RX160iN can operate on natural gas or propane and can be installed indoors or outdoors with the required configuration. Rinnai lists up to 9 GPM, capacity for up to six fixtures, and a UEF of 0.97. Its Quick Flush feature is designed to simplify flushing.
This model offers a different trade-off from a near-200,000 BTU unit: the supplied features emphasize flexibility and efficiency rather than a stated 200,000 BTU rating. Outdoor installation requires an RX-OVC vent cap, and Wi-Fi control requires a separately sold Controlr module. Verify the exact installation configuration with a qualified professional.
Rinnai RE180iP Indoor Propane Heater
Best for: Propane homes seeking a compact indoor unit with substantial listed flow. The RE180iP provides up to 8.5 GPM and is described as supporting up to seven fixtures. Its LED screen displays service reminders and error codes, while its internal layout is designed to support installation and service access.
The product is non-condensing and intended for indoor installation. The listed residential coverage is 15 years for the heat exchanger, five years for parts, and one year for labor. Wi-Fi control requires a separate Controlr module. Choose this model for propane and indoor placement; its listed features do not identify it as a 200,000 BTU unit.
Buying Guide: How To Choose A High-BTU Tankless Heater
Is 200,000 BTU the right capacity?
BTU input describes the heater’s fuel input, but it does not by itself determine how many fixtures can run at once. Compare the GPM rating at the temperature rise relevant to your location. Colder incoming water requires more heating, which can reduce the flow available at the desired output temperature.
Which fuel and installation location do you need?
Match the unit to the home’s available natural gas or propane supply. Then confirm whether indoor or outdoor installation is appropriate. Indoor models require a compatible venting arrangement; outdoor models avoid indoor venting but must be suitable for local weather and installed according to the manual and local codes.
How much simultaneous hot water do you use?
Estimate which fixtures are likely to run together, such as showers, faucets, laundry, or a dishwasher. Compare that demand with the heater’s flow rating at the expected temperature rise. A maximum GPM figure without its operating conditions may not represent performance during a cold winter morning.
What installation details should be checked?
Ask a qualified installer to assess gas-line capacity, electrical requirements, water connections, venting or outdoor placement, and local permitting. Also review maintenance access and any separately required accessories. Do not assume that standard connection sizes or a compact cabinet mean the unit is a direct replacement for an existing heater.
Frequently Asked Questions
Which listed model is closest to 200,000 BTU?
The Rinnai RE199iN is listed at 199,000 BTU, making it the closest match. The APUS model is rated at 190,000 BTU.
Does a 200,000 BTU rating guarantee a certain GPM?
No. Delivered flow depends on incoming water temperature, desired output temperature, and the unit’s operating conditions. Compare GPM at a relevant temperature rise.
Can a tankless heater supply several fixtures at once?
Yes, if its available flow at the required temperature rise meets the home’s combined demand. Check the manufacturer’s stated simultaneous-use guidance and have the system sized professionally.
Do these models include Wi-Fi control?
Features vary. Some list app control, while the Rinnai RE199iN, RX160iN, and RE180iP require a separately sold Controlr module for Wi-Fi monitoring or control.