11 Best 11 GPM Tankless Water Heater | 7+ Fixtures, No Wait

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The Rinnai RX199iN is a condensing unit that delivers 11.1 GPM at 199,000 BTU with a UEF rating of 0.98 — the highest efficiency in our list. Its Smart Sense gas control system automatically switches between natural gas and propane, and the Versa Vent design allows both indoor and outdoor installation without needing a separate vent kit for the exterior mount.

Owners report consistent hot water for households of five across multiple simultaneous showers. The condensing design captures exhaust heat pre-combustion, which lowers gas consumption noticeably compared to non-condensing alternatives. The interface is intuitive, and the Quick Flush feature simplifies annual descaling.

The Controlr module for WiFi is sold separately, which adds cost if you want app-based temperature scheduling. At 55 pounds and 30 inches tall, it requires solid wall anchoring and adequate clearance for the exhaust. Professional installation is strongly advised given the gas line sizing and venting complexity.

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The CX199iN is Rinnai’s commercial-grade condensing unit rated for 11.1 GPM with a 97% thermal efficiency. It includes a Smart Sense gas control that accepts either natural gas or propane out of the box, and the Versa Vent system supports indoor or outdoor installation. The commercial designation means the heat exchanger is built to sustain near-continuous draw without overheating.

Buyers replacing 18-year-old tank heaters report drops of 360 kWh in monthly electric consumption after switching. The unit handles eight-person households with simultaneous laundry and shower usage. The Bluetooth connectivity through the Rinnai Central App enables troubleshooting and temperature monitoring without a separate module.

The CX199iN is taller and heavier than residential models, and the 3-inch PVC venting system must be correctly sized for the run length. A recirculation conversion kit is available but sold separately, and installers need to ensure the gas meter is rated for the total BTU load.

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The Rinnai RU199iN is the brand’s established condensing model with Circ-Logic technology, designed to pair with an external recirculation pump for near-instant hot water at distant fixtures. It delivers 11 GPM at 199,000 BTU and supports up to 7 fixtures simultaneously. The unit is ENERGY STAR qualified and carries a 15-year heat exchanger warranty.

Long-term owners consistently note stable temperature output during back-to-back showers and lower gas bills compared to previous tank systems. The unit is noticeably quiet even when the burner is at full fire. The Cold sandwich reduction technology minimizes temperature bursts when a second fixture opens.

Some units arrive missing the union fittings for the isolation valves, requiring a call to Rinnai support for replacements. The initial cold-water delay to upper floors can be 10-15 seconds longer in winter, and annual flushing with a descaling kit is essential in hard water areas to maintain flow rate.

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The Westinghouse Smart 199k is a non-condensing unit delivering 10.3 GPM with 199,000 BTU input. Its standout feature is native WiFi app and voice control via Amazon Alexa and Google Assistant, allowing you to adjust temperature from anywhere. The 1:20 turndown ratio and 6-stage combustion system improve efficiency during low-flow periods.

Users report stable ±1°F temperature control and reliable freeze protection down to -13°F, making it suitable for colder climates when installed in a conditioned indoor space. The phosphorus-deoxidized copper heat exchanger provides faster heat transfer than standard copper. The CSA certification covers safety compliance.

The unit is large at 24.8 inches tall and requires clearance for the non-condensing exhaust vent. The app setup occasionally needs a firmware update to connect reliably. Some buyers note that the remote controller is basic compared to the smartphone app, and gas line sizing must be verified for full BTU output.

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The MIZUDO 199k is a non-condensing indoor unit rated at 199,000 BTU and 10.3 GPM, targeting households with 5-to-7 simultaneous fixtures. It features 16 integrated safety mechanisms including freeze protection down to -13°F and a sealed direct vent system that draws outside air for combustion, preserving indoor air quality.

Buyers report that the unit heats water quickly and maintains stable temperatures during multiple draws. The compact design (24.8 x 15.9 x 10.4 inches) fits in tight utility spaces, and the standard 3/4-inch NPT connections simplify plumbing. The WiFi app enables remote temperature scheduling and maintenance alerts.

The gas inlet fitting is non-standard, so you may need an adapter for a 1/2-inch gas line. Some users note that the 80,000 BTU variant struggles with tub fill speeds, so confirm you are purchasing the 199,000 BTU version for whole-house demand. The direct vent kit is not included and must be purchased separately.

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The Rheem RTG-95XLN-3 is a non-condensing outdoor natural gas unit delivering 9.5 GPM with 199,900 BTU. Designed specifically for outdoor wall mounting, it eliminates indoor venting concerns and frees up floor space. The Hot-Start programming prevents the cold-water burst that often occurs between back-to-back showers.

Users report reliable operation for 2-to-3-bathroom homes, with consistent hot water for simultaneous shower and laundry use. The durable metal cabinet withstands weather exposure, and the unit is pre-configured for natural gas, reducing setup complexity. The digital temperature display allows quick adjustment.

The outdoor pipe cover kit must be purchased separately to protect the water and gas connections from the elements. Some installers note that the back panel feels thinner than previous Rheem generations. The flow rate of 9.5 GPM is slightly below the 11 GPM threshold, so it is best suited for moderate-demand households rather than large simultaneous draws.

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The Rheem RTG-95DVLP-3 is the indoor propane variant of the RTG series, delivering 9.5 GPM at 199,900 BTU. It includes a 15-year heat exchanger warranty and a 5-year parts warranty, which is one of the strongest coverage terms among non-condensing units. The Hot-Start feature is particularly valuable for households that run back-to-back showers on LP.

Buyers find the installation straightforward using PEX connections, with many completing the job in a few hours with a helper. The unit holds temperature well even at high altitudes up to 8,000 feet, making it a solid choice for mountain homes. The compact metal cabinet fits into tight utility closets.

Several owners note that the unit is louder than expected during full-fire operation, comparable to a low-end dishwasher. The exhaust and intake pipes must be correctly sized for the specific vent run, and condensation management is necessary for the PVC venting. The propane consumption is efficient, but the unit requires a standard 120V outlet for the control board.

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The Ranein 190k is a non-condensing natural gas unit rated at 190,000 BTU and 8.5 GPM, designed for 4-to-6 outlet points. The fans underneath the combustion chamber prevent smoke backflow and provide stable combustion even with variable external wind pressure. The unit is 42 pounds and compact at 24.25 x 15.08 x 8.07 inches.

Owners running on propane report significant monthly savings compared to older tank heaters, with one user noting the unit paid for itself in three months. The heater maintained consistent temperatures through winter freezes without cracking lines. Installation is reported as manageable for experienced DIYers, taking roughly two hours.

The maximum water pressure rating is 116 PSI, which is lower than the 150 PSI common on premium units, so a pressure regulator may be necessary. The manufacturer recommends against use in areas above 2,000 feet elevation due to reduced combustion efficiency. Customer service has been responsive, sending replacement units for part failures within the 2-year warranty period.

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The GASLAND CE686NG is a non-condensing natural gas unit delivering 7.6 GPM with 199,000 BTU input. It is CSA certified and features a UEF of 0.8, making it 34% more efficient than a standard 50-gallon tank water heater. The compact suitcase-sized design weighs 37.5 pounds and fits into closets or basements.

Buyers with recirculation systems report the unit pairs well with existing pumps. The copper piping and integrated temperature display add convenience. The 1-year free replacement warranty from US-based support provides clean coverage for early defects.

The manufacturer states 7.6 GPM at a 35°C rise, but real-world flow may be lower in northern climates with colder groundwater. One user experienced a failure after three months and reported the unit is classified as non-returnable after installation. The inlet and outlet spacing is uneven, making some plumbing layouts more difficult. The unit is not ENERGY STAR certified, so it may not qualify for local utility rebates.

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The WINTEMP WN36 is a 36 kW electric tankless unit rated at 8.7 GPM with 240V input. It requires 4 x 40 amp double-pole breakers and 4 x 8/2 AWG cables, demanding a 300 amp household service minimum. The ETL certification and multiple safety protections cover leakage, overheat, and dry-fire scenarios.

The WiFi control allows temperature adjustment from a smartphone, and the self-modulating technology aims for 99% energy savings by reducing power during low flow and consuming zero when idle. Compact dimensions (13.7 x 21.1 x 5.3 inches) and 36-pound weight make wall mounting straightforward.

The maximum flow of 8.7 GPM is below the 11 GPM threshold, and the sustained output drops further if the incoming water temperature is below 50°F. The mounting system uses picture-hanging-style holes rather than a solid bracket, which may feel less secure. Several customers report inconsistent heating where the unit randomly stops heating during showers, and the cheap-feeling casing clips are difficult to snap closed.

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The Westinghouse 5.1 GPM is a non-condensing outdoor natural gas unit with 120,000 BTU input, designed for 2-to-4 fixtures. The ±1°F self-modulating temperature control system adjusts gas and water flow to minimize cold bursts. It is CSA certified with integrated freeze protection and a variable-speed fan.

Buyers praise the very easy step-by-step installation instructions and the solid build quality. The unit delivers consistent 116°F water without requiring cold water mixing. The wired remote control panel provides convenient temperature adjustment from a nearby location.

The 5.1 GPM flow rate is significantly below the 11 GPM category, so this unit is only suitable for small apartments or cabins with low simultaneous demand. The outdoor installation requires the unit to be connected to a 120V AC power source, and temperatures below 5°F require full drain-down to prevent freeze damage. Delayed hot water of 1-2 minutes is common for fixture locations far from the unit.