Rinnai RE140iN
The Rinnai RE140iN is a compact, indoor, non-condensing natural-gas tankless heater rated at 140,000 BTU/h and a maximum 5.3 GPM. It's built for small-to-medium homes that want into the Rinnai ecosystem — the long heat-exchanger warranty, the nationwide service network, and the option to bolt on Wi-Fi and recirculation later — without paying condensing-unit prices.
As a non-condensing model it runs at 0.81 UEF, trading a few points of efficiency for a lower purchase price and simpler 3-in/5-in concentric venting. It modulates from 10,400 up to 140,000 BTU/h, activates at just 0.4 GPM, and holds a set temperature between 120 and 140 °F. At 38.5 lb and roughly the size of a small suitcase, it fits where a tank never could.
Key Features
Best Use Cases
Our Verdict
The RE140iN is the right call when you want a genuinely small, reliable gas tankless and your peak demand is modest — roughly two fixtures at once. Its 5.3 GPM ceiling is the honest limit: plenty for a couple showering back-to-back or a shower plus a sink, but not a whole-house workhorse for a large, cold-climate home. What you're really paying for is the platform — Rinnai's 15-year heat-exchanger warranty, a nationwide service network, quiet 54 dB operation, and the option to add Wi-Fi and recirculation later. Our take: the best-value entry into the Rinnai ecosystem for a small home — buy it for the warranty and reliability, and size up to the RE160i or RE199i if you have a big or cold-climate house.
What owners report
Themes summarized from verified-purchase reviews across major retailers (4.4★ average, 73 ratings). These are aggregated owner opinions — not our own bench testing.
Endless, consistent-temperature hot water once it reaches the tap; owners note it heats water well and is easy to adjust.
Compact, suitcase-sized footprint and a straightforward indoor install for a gas unit.
Reliable in the first year of ownership, with quiet operation.
Wait time for hot water to reach distant fixtures — the classic tankless lag, which an add-on recirculation pump addresses.
Some installs need extra components (correct gas-line sizing, venting), so budget for professional installation.
Rinnai RE140iN FAQ
Can the RE140iN run a whole house?+
It depends on your climate and how many fixtures run at once. At 5.3 GPM max it handles two simultaneous fixtures in a warm climate, but in cold climates its usable flow drops to roughly 3.2 GPM — enough for one shower plus a sink. For a large or cold-climate home, step up to the RE160i or RE199i.
Does it have Wi-Fi and a recirculation pump?+
It's capable of both, but neither is built in. Wi-Fi (remote monitoring and recirculation control) requires Rinnai's Control-R module, and recirculation requires an external pump — both sold separately. Out of the box it's run by its integrated front-panel controller.
Is it condensing or non-condensing?+
Non-condensing, at 0.81 UEF. That means a lower purchase price and simpler 3-in/5-in concentric venting, but slightly higher gas use than a condensing unit (typically 0.90+ UEF). It's a deliberate value trade-off.
What's the warranty?+
15 years on the heat exchanger (or 12,000 operating hours, whichever comes first), 5 years on all other parts, and 1 year of reasonable labor — one of the longest coverages in its price class.
Can it be installed at high altitude or in a mobile home?+
Yes. It's approved up to 10,200 ft and is mobile-home certified. It also meets Ultra-Low-NOx emissions requirements, so it's approved in strict air-quality districts.
Price range from leading retailers
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