13 Best 80 Gallon Gas Water Heater | 11.1 GPM Whole-Home Heat

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The Rinnai RXP199iN is the most complete package in this category. It delivers up to 11.1 GPM and 199,000 BTU with a UEF of 0.98, meaning virtually all the gas energy goes into heating your water. The built-in Smart-Circ recirculation pump learns your household’s usage patterns and pre-heats the line, so you get hot water almost instantly at any tap. This unit installs indoors or outdoors using the Versa Vent system and automatically adapts to either natural gas or propane.

Families of five or more will appreciate the RXP’s ability to run a dishwasher, washing machine, and two showers simultaneously without any temperature fluctuation. The stainless steel heat exchanger resists corrosion in hard water areas, and the Quick Flush feature makes annual descaling straightforward. It’s compatible with the optional Controlr module for WiFi monitoring via the Rinnai Central App.

Noise from the recirculation pump is noticeable in economy mode, but most users find it acceptable when the unit is installed in a garage or mechanical room. The app functionality has room for improvement, but the core hot water performance is outstanding. For a family that values instant hot water and energy savings, this is the top pick.

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The Rinnai CX199iN brings commercial-grade construction to the residential market. With a 97% thermal efficiency rating and up to 11.1 GPM, this unit is built for homes with extreme hot water demands or light commercial applications like a small apartment building or salon. Like the RXP, it works with both natural gas and propane and supports indoor or outdoor installation via the Versa Vent system.

Users report significant energy savings — one reviewer noted saving 360 kWh in the first month compared to a heat pump hybrid. The Smart Sense gas control automatically adjusts fuel type without a conversion kit, and the optional recirculation conversion kit adds flexibility for homes with long pipe runs. The stainless steel heat exchanger and robust internal components are designed for continuous high-demand use.

This is a heavier unit and requires professional installation to ensure proper gas line sizing and venting. The taller chassis may need plumbing adjustments compared to older models. For a large household or a property manager looking for maximum durability, the CX199iN is a serious investment that performs like a workhorse.

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The Rheem Prestige is the only unit in this lineup with Auto-Learn programming, which tracks your household’s water usage over time and automatically pre-heats during peak periods. It delivers 11.0 GPM at 199,000 BTU with a UEF of 0.94, making it one of the more efficient condensing options. The built-in recirculation pump reduces wait time for hot water, and the water and gas leak detection system adds peace of mind.

The compact, space-saving design is intended for easy tank replacement. The warranty is strong — 25 years on the residential heat exchanger and 5 years on parts. When the unit works correctly, it provides instant, continuous hot water and eliminates morning shower conflicts.

Reliability is the major concern here. Customer reviews consistently report failures including cracked heat exchangers, constant error codes, and ineffective recirculation within the first two years. Rheem’s customer service and warranty resolution have drawn sharp criticism. For a premium-priced unit, the failure rate is higher than acceptable.

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The Rinnai RU199iN has been a trusted choice for years, and its long track record of reliability speaks for itself. It supplies up to 11 GPM and 199,000 BTU with a condensing design that reaches a UEF of 0.105 (ENERGY STAR qualified). The Circ-Logic feature allows pairing with an external recirculation pump for scheduled or on-demand hot water delivery, reducing waste while you wait.

Users consistently praise the stable water temperature — even when running multiple showers, the dishwasher, and the washing machine simultaneously. The compact footprint saves floor space in the garage or utility room. Many reviewers report lower natural gas bills after switching from a traditional tank. The unit has been in service for years without issues for many owners.

Professional installation is recommended, and some Amazon installers may refuse to install units not purchased through their program. The unit itself is quiet during operation, though there is a brief 10-15 second cold-start delay. For a reliable, high-performance condensing unit with a proven history, the RU199iN is a confident pick.

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The Rinnai RX199iN is the Smart Sense evolution of the classic RU series, bringing a UEF of 0.98 and the ability to install indoors or outdoors using Versa Vent. At 11.1 GPM and 199,000 BTU, it supports up to 7 fixtures simultaneously. The Smart Sense gas control automatically detects whether you’re using natural gas or propane, simplifying installation.

The Quick Flush feature makes maintenance much easier — no need for a plumber just to descale the heat exchanger. The compact size (18.5″W x 30.11″H) fits neatly into tight spaces. Users report quiet operation and consistent hot water for large families, with some noting that water reaches distant bathrooms faster than their previous tank heater.

The RX199iN does not include a built-in recirculation pump, so if instant hot water at every tap is critical, you’ll need to add an external pump or step up to the RXP model. It also requires an RX-OVC vent cap for outdoor installation. For a high-efficiency unit that balances performance and price, the RX199iN is a strong contender.

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Westinghouse brings smart home integration to the tankless category with this 10.3 GPM, 199,000 BTU unit that offers WiFi app control and voice command compatibility. You can adjust temperature, monitor operating status, and receive fault alerts from your phone. The ±1°F temperature stability ensures no cold bursts during back-to-back showers.

The wide 1:20 turndown ratio and 6-stage combustion system optimize gas usage based on real-time demand. This means it can handle small loads like washing hands efficiently while still delivering full power for multiple showers. The integrated freeze protection works down to -13°F, making it suitable for colder climates when installed indoors with proper protection.

Some users report a slight delay in hot water reaching distant fixtures, which is typical for non-recirculating tankless units. The WiFi connectivity adds convenience, though the app interface could be more polished. For homeowners who want energy-efficient on-demand heating with the convenience of remote control, this is a compelling mid-range option.

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The Rheem RTG-95DVLN-3 delivers impressive flow at 9.5 GPM with 199,900 BTU, making it one of the highest-flow non-condensing indoor units available. The Hot-Start programming prevents the cold water sandwich effect that plagues some tankless heaters, so back-to-back showers stay comfortable. The compact metal cabinet measures 13.5″W x 24.2″H and weighs just 46.5 pounds.

Installation is relatively straightforward for a qualified professional, especially if replacing an existing Rheem tankless unit — the hosing and venting connections are identical to previous generations. Users report noticeable drops in their gas bills compared to traditional tank heaters. The warranty covers 15 years on the heat exchanger and 5 years on parts.

A few users have reported the unit failing within the first year, and some noted that critical parts like venting must be purchased separately, adding to the total cost. The non-condensing design means lower efficiency (UEF 0.82) compared to premium condensing units. For households that need high flow without the complexity of condensing technology, this is a solid mid-range pick.

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This Rheem RTGH95DVLP3701178 is built specifically for liquid propane, making it an excellent choice for homes not connected to natural gas lines. It delivers 9.5 GPM with 199,900 BTU and features a wide temperature range from 100°F to 140°F. The electric ignition and durable stainless steel construction are designed for long-term outdoor or indoor installation.

Users praise its ability to handle low-temperature incoming water well, which is a common pain point with propane tankless units in colder regions. The warranty is robust: 15 years on the heat exchanger and 5 years on parts. The unit is slightly heavier at nearly 60 pounds, but the build quality feels substantial.

The primary concern is Rheem’s inconsistent quality control. Some buyers have received defective units with error codes and faced a frustrating non-returnable policy combined with poor customer service. The separate purchase of venting and gas line components adds to the upfront investment. For propane users who need a high-flow solution, this unit performs well when it works.

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Takagi has a long-standing reputation in the tankless space, and the T-H3S-DV-N is a condensing unit that satisfies 2012 SCAQMD Rule 1146.2 for ultra-low NOx emissions. At 8.0 GPM, it’s best suited for 2-3 bathroom homes rather than larger households. The condensing design captures additional heat from exhaust for better overall efficiency.

Users with prior Takagi experience report straightforward replacement installations because the mounting and connections are often identical to older models. The unit operates quietly and delivers stable hot water temperature. Many owners report years of trouble-free service, reinforcing the brand’s reliability reputation.

The biggest hidden costs are the biannual descaling requirement (critical in hard water areas) and the likely need for a 3/4″ gas line instead of the common 1/2″ pipe. The unit is also non-returnable, so confirming compatibility with a professional installer before purchase is essential. For eco-conscious buyers with moderate hot water needs, the Takagi delivers efficient performance.

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The A. O. Smith ATI-310CX3 stands out for its X3 Scale Prevention Technology, which uses a built-in filter and proprietary design to reduce scale buildup without requiring annual descaling or isolation valves. It delivers 8.0 GPM at 190,000 BTU with a non-condensing design. The commercial-grade copper heat exchanger provides 25x better heat transfer compared to steel.

The unit includes a propane conversion kit, so you can switch fuel types without buying additional parts. Safety features include exhaust and water temperature safety controls, an overheat cut-off fuse, and an air-fuel ratio sensor. Users consistently report consistent hot water temperature even with multiple fixtures running, and the quiet operation is frequently noted.

Professional installation is strongly recommended because of the complex gas and venting requirements. Some users have found that balancing valves in their shower can cause the unit to shut down, requiring a cold water restrictor to solve the issue. The 8.0 GPM flow rate means it’s better for 2-3 bathroom homes than for very large households.

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This Westinghouse outdoor propane tankless unit is designed to free up indoor space while delivering 8.1 GPM and 180,000 BTU for 3-5 fixtures simultaneously. The ±1°F temperature stability ensures a consistent shower experience, and the included indoor remote control panel makes temperature adjustments convenient without having to go outside.

Construction includes integrated freeze protection, a variable-speed combustion fan, and durable internal components for year-round outdoor performance. Users consistently praise easy installation, with clear step-by-step instructions and straightforward startup. The ability to set a specific temperature (e.g., 116°F) and not need to mix cold water is a frequently mentioned benefit.

The outdoor location means longer wait times for hot water to reach distant indoor fixtures, though this is typical for any tankless unit without recirculation. Finding a contractor willing to install an outdoor gas heater can be challenging in some areas. The included remote adds convenience, but the unit requires a 120V AC power source.

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The Rheem RTG-70DVLN-3 is a solid entry-level tankless unit designed for 2-3 bathroom homes. It delivers 7.0 GPM at 160,000 BTU, which is sufficient for running a shower and a couple of sinks simultaneously but may struggle with higher demand. The Hot-Start programming helps prevent the cold water sandwich effect, and the compact 46.5-pound cabinet is easy to mount.

Users who have upgraded from traditional tank heaters report satisfaction with the endless hot water and lower energy bills. The display provides easy access to temperature settings and diagnostic information. The warranty is decent: 15 years on the heat exchanger and 5 years on parts.

The 7.0 GPM flow rate is the limiting factor. For a home with only two bathrooms and moderate usage, it works fine, but adding a second shower or running the dishwasher simultaneously may result in noticeable temperature drops. The unit requires special venting pipe, which adds to the installation cost. Some users report a longer wait for hot water compared to tank systems.

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The Rheem RTG-70XLN-3 is the outdoor counterpart to the RTG-70DVLN-3, offering the same 7.0 GPM and 160,000 BTU performance in a weather-resistant outdoor cabinet. By mounting outside, you save indoor space and eliminate the need for complex venting. The Hot-Start programming and durable metal cabinet are standard, and the unit is slightly lighter at 39.25 pounds.

Users appreciate the simplicity of outdoor installation — no vent pipes to run through the roof or wall. The unit delivers consistent hot water for 1-2 bathroom homes, and many DIY-inclined homeowners find the installation manageable. The price point is attractive for those wanting to try tankless technology without a major investment.

Performance is limited by the 7.0 GPM flow rate. Running multiple showers simultaneously may cause noticeable temperature drops. Some users have reported receiving units with damaged packaging or defective components, and Rheem’s customer service has been criticized for poor responsiveness. Outdoor installation also requires freeze protection measures in colder climates.