Our readers keep the lights on and my morning glass full of iced black tea. As an Amazon Associate, I earn from qualifying purchases.11 Best 40 Gallon Propane Water Heater | Outlast Your Old Tank

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The Rinnai RX199iN represents the highest tier of residential tankless water heating. Its 199,000 BTU burner delivers up to 11.1 GPM, enough to supply seven fixtures simultaneously without noticeable drop-off. This is a condensing unit, which captures extra heat from exhaust gases to achieve a UEF of 0.98 — about 20% more efficient than most non-condensing models. The heat exchanger uses a dual-stainless design that resists corrosion better than copper-based exchangers in aggressive water conditions.

Installation is flexible: the RX199iN can be mounted indoors or outdoors using Rinnai’s Versa Vent system and RX-OVC vent cap for outdoor setups. It runs on either natural gas or propane thanks to the Smart Sense gas control, which auto-detects fuel type. Users consistently report fast hot water delivery even at long pipe runs, though the recirculation pump is not built in — you’ll need an external solution or the optional Controlr module for wifi scheduling.

Owner feedback highlights quiet operation and reliable temperature maintenance across multiple outlets. Some note the unit’s 55-pound weight requires a sturdy wall mount, and professional installation is strongly recommended. The 15-year heat exchanger warranty covers long-term corrosion protection, a sign of confidence in the stainless steel construction.

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The Rinnai RXP160iN distinguishes itself with a built-in Smart-Circ intelligent recirculation pump. This pump learns your household’s water usage patterns over the first few weeks and preheats the hot water line at the times you actually need it, reducing the wait time and wasted water from long pipe runs. It delivers 9 GPM at 160,000 BTU, a pairing that comfortably covers up to six fixtures at once for most 3-bathroom homes.

As a condensing unit, it achieves a UEF of 0.97, placing it among the most efficient propane tankless water heaters available. The Versa Vent system allows indoor or outdoor installation, and the Smart Sense gas control switches seamlessly between natural gas and propane. The compact chassis weighs 57 pounds and measures 31 inches tall, making it manageable for a two-person lift during mounting.

User reports praise the fast hot water delivery once the learning cycle completes, though some note that initial hot water arrival can take 2-3 minutes in larger homes without recirculation active. The Bluetooth module (sold separately) enables on-demand paging for a 5-minute recirc cycle, which balances convenience with energy savings. The main ongoing cost is annual descaling — standard for all tankless units in hard water areas.

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Rheem’s RTG-95DVLP-3 packs a 199,900 BTU burner into a non-condensing indoor package that delivers 9.5 GPM. This is the top flow rate in Rheem’s residential RTG lineup, designed for 3-bathroom homes where simultaneous showers, laundry, and dishwashing are the norm. The Hot-Start programming minimizes the cold-water sandwich effect between back-to-back uses, a common complaint with older tankless designs.

The aluminum heat exchanger and stainless steel burner are engineered for longevity, backed by a 15-year heat exchanger warranty. Installation requires a dedicated 3-inch PVC vent system and a 3/4-inch gas line with an adequate regulator — users caution against using a standard BBQ regulator, as the burner needs higher volume and pressure to reach full output. The unit weighs 46.5 pounds and measures 24.2 inches tall, compact enough for closet or basement mounting.

Owner experiences are generally positive, with many reporting easy DIY installation when accompanied by Rheem’s recommended vent kit. Some mention the fan is louder than expected — comparable to a low-end dishwasher — but the performance consistency earns high marks. A few negative reviews cite cold spots or ignition issues, likely tied to insufficient gas supply rather than the unit itself.

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The RTG-70DVLP-3 steps down slightly from its bigger sibling but still delivers a strong 7 GPM at 160,000 BTU, enough for 2 to 3 bathrooms running concurrently. It uses the same Hot-Start technology to prevent cold bursts, and the non-condensing design keeps the upfront cost lower than condensing alternatives. The UEF rating of 0.82 is solid for a non-condensing unit and represents a meaningful efficiency gain over a traditional tank heater.

Indoor installation requires a 3-inch vent system and adequate gas line sizing. The compact metal cabinet (13.5 x 24.2 inches) fits neatly into mechanical closets or utility rooms. Rheem’s warranty structure provides 1 year labor, 5 years parts, and 15 years on the heat exchanger — a term that reflects confidence in the cast-aluminum heat exchanger’s durability in standard residential water conditions.

User reviews highlight reliable performance in family settings, with one owner running it for a household of 6 people including 4 kids taking long showers. Some report receiving a natural gas unit instead of the LP model they ordered, so verify the packaging label on delivery. A small number of buyers experienced cold spots or loud fan noise, but the majority rate it highly for consistent hot water delivery and straightforward installation.

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APUS pushes the high-volume envelope with this outdoor-rated 190,000 BTU model that flows up to 8.1 GPM, designed to supply 3 showers and 2 faucets simultaneously. The oxygen-free copper heat exchanger claims 30% higher efficiency than conventional copper exchangers, and the intelligent staged combustion technology fires only the burners needed for the current demand, reducing propane consumption by about 20% compared to full-fire operation.

The outdoor enclosure features wind-resistant construction rated to Level 10 winds and electric anti-freeze protection, making it viable in exposed locations. WiFi connectivity via the Tuya app allows temperature adjustment from 95°F to 149°F, usage monitoring, and system alerts. The minimum flow activation of just 0.79 GPM means it will fire even with low-flow fixtures, a practical advantage in homes with older plumbing or water-saving aerators.

Users consistently praise the quiet operation and the reliability of the on-demand heating. A few note that you’ll need to purchase an external valve body separately if your existing setup doesn’t have one, and heat tape or foam insulation on water lines is recommended for cold climate installations. Overall, it delivers premium flow capacity at a competitive price point.

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GASLAND’s CE686LP brings a 199,000 BTU non-condensing indoor unit to the table with a UEF of 0.8, rating it 34% more efficient than a standard 50-gallon tank heater. The flow rate of 7.6 GPM is suitable for 3+ bathrooms, and the compact suitcase-style chassis (24.69 x 14.25 x 7.28 inches) slots into tight spaces like closets and laundry rooms where a tank unit wouldn’t fit.

Safety features include overheat protection, flame-out detection, and freeze protection for indoor use. The included components cover wall-mounting hardware and a manual, but users report that the pressure relief valve and vent kit must be purchased separately. The gas inlet and water connections are standard 3/4-inch NPT, which simplifies integration with existing plumbing. CSA certification confirms compliance with US safety standards.

Owner feedback highlights the unit’s ability to keep up with a family of 4 with a large soaking tub, and many appreciate the energy savings from on-demand firing. Some note the fan noise is noticeable but not intrusive, and the mounting ledge design on some units made screw tightening tricky during installation. The manufacturer offers a free replacement within the first year if the unit stops working, backed by US-based customer support.

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Westinghouse enters the outdoor tankless space with a 120,000 BTU unit rated for 5.1 GPM, targeting households with 2 to 4 simultaneous fixtures. The self-modulating technology adjusts gas and water flow in real time to maintain output temperature within ±1°F, which effectively eliminates the cold bursts that plague cheaper units when someone flushes a toilet or turns on a second faucet.

The outdoor-rated chassis includes freeze protection for year-round operation, and the included wired remote control panel mounts indoors so you can adjust temperature without going outside. Connections are standard 3/4-inch NPT, and the unit requires a 120V AC power source. CSA certification covers safety standards, and Westinghouse’s reputation for warranty support adds confidence for a first-time tankless buyer.

Users report very straightforward installation — some completed the swap from an old tank in under two hours. Remote control functionality is praised for its clear LED display and easy temperature setting. A minor complaint involves the wait time for hot water at fixtures far from the heater, which is typical for tankless systems without recirculation. Overall, it’s a solid pick for those wanting a simple outdoor install with reliable temperature regulation.

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FOGATTI’s Instagas Comfort 120S packs 120,000 BTU into a compact outdoor chassis measuring just 26.2 x 17.1 x 7.1 inches — about a third the size of a traditional tank heater. It delivers 5.1 GPM, enough for 2 to 4 outlets in a medium-sized home. The four-stage combustion system and water servo technology work together to maintain temperature within ±1°F, even when outdoor temperatures fluctuate between summer heat and winter cold.

The heat exchanger is high-efficiency copper, paired with a 304 stainless steel burner for corrosion resistance. The unit requires a 120V AC power connection and operates at water pressures between 15 and 150 PSI, which covers most residential well and municipal systems. Active anti-freeze protection is included, but FOGATTI recommends fully draining the unit if ambient temperature drops below 5°F or during extended non-use. CSA certification verifies safety compliance.

Owners frequently mention the unit’s quick water heating and the convenience of the outdoor mount freeing up indoor space. A few users report intermittent ignition failures, and some caution that the unit may be less reliable than larger brands like Rheem or Rinnai. The warranty covers 2 years full unit and 5 years on the heat exchanger, and customer service responsiveness gets mixed marks in recent reviews.

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The MIZUDO GEN 3 is the only unit in this lineup that ships standard for indoor installation but can convert to outdoor with an accessory vent cap kit. This flexibility is valuable for homeowners who might move or remodel, as the same unit adapts without needing a full replacement. The 120,000 BTU burner supplies 5.1 GPM for large families, and the phosphorous-deoxidized copper heat exchanger combined with a stainless steel combustion chamber targets long-term corrosion resistance.

WiFi and app control via the dedicated MIZUDO app allows remote temperature setting and energy monitoring. Four safety systems — freeze protection, dry burn prevention, flame failure detection, and exhaust blockage protection — are standard. The unit measures 22.83 x 14.56 inches, and installation requires a 3-inch vent pipe for indoor use. CSA certification covers all US safety requirements.

Early users appreciate the fast heating and quiet operation, with many reporting installation times of a few hours. A common complaint involves the gas inlet fitting being non-standard — some buyers needed an extra trip to the hardware store for adapters. Package contents include an outdoor fume hood for convertible use, but the vent cap for outdoor installation must be purchased separately. Overall, the flexibility and build quality make it a compelling mid-range option.

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APUS offers a smart indoor solution with a 140,000 BTU burner that flows 6.8 GPM, supporting 2 showers and 2 sinks simultaneously. The defining feature is the built-in booster pump, which increases water flow by up to 130% to deliver a maximum of 6.8 GPM even when incoming pressure is low. The exclusive single-circulation technology eliminates cold water wait time by pre-warming the line on demand — a feature rare in this price range.

The Tuya smart app provides full remote control: temperature adjustment across 95°F to 140°F, performance monitoring, and system alerts. The ECO smart cycle operates 24/7, claiming 40% energy savings versus conventional tank heaters. Eight protection systems include freeze and overheat protection, and the bottom turbo fan design runs 30% quieter than standard tankless fans. The compact chassis (21.3 x 13.6 x 7.1 inches) fits into standard mechanical spaces.

User feedback is highly positive regarding hot water delivery speed and stable temperature. The recirculation feature surprised some owners, but those who understood it valued the instant hot water. A few negative reports cite ignition defects on arrival, and some users recommend spending more on a Rheem if reliability is the top concern. The unit includes a 2-year warranty on components.

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CAMPLUX’s Climatech WA528 is an outdoor-only propane tankless heater rated for 150,000 BTU and 5.28 GPM, with a peak flow of 6.4 GPM. It supports 3 to 5 water points — for example, three bathrooms plus a laundry room and kitchen — making it a strong candidate for medium-sized homes. The CSA certification covers anti-freeze, overheat, dry-fire, and flame failure protections, providing a safety baseline often missing from budget-oriented outdoor units.

The unit measures 23.43 x 5.91 x 14.92 inches, mounts easily on an exterior wall, and requires standard 3/4-inch NPT water and gas fittings. It does not need a vent pipe since combustion occurs outdoors, and the aluminum construction keeps weight at 31.3 pounds. The remote control (included) allows temperature adjustment from inside the home, and the smart chip with three-speed automatic flame row adjustment claims ±1°F temperature stability.

Users frequently highlight ease of installation — some completed the job in about an hour — and consistent performance even with low water pressure down to 24 PSI. The customer service reputation is strong, with several owners reporting responsive warranty replacements. A few concerns include the aluminum heat exchanger being less durable than copper over the long term, and the unit’s freeze protection requiring proactive draining in severe climates.