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Written from the listing and 16 buyer reviews, not from our own use · How we rate
The Rinnai RE180iN Non-Condensing packs a 6.9 GPM maximum flow and a 15-year heat exchanger warranty into one indoor gas tankless heater. A good match for a two-bathroom house with one shower running at a time, with 16 buyer reviews averaging 4.4/5.
These are sold as variants of one listing family. Each variant has its own page.
| Brand | Rinnai |
|---|---|
| Category | Gas tankless water heaters |
| Fuel | Natural gas |
| Stated mounting location | Indoor |
| Stated maximum flow | 6.9 GPM |
| Wi-Fi | With an optional module |
| Stated warranty | 15 years on the heat exchanger |
| Buyer reviews | 16 · 4.4/5 |
| ASIN | B0B57PQYLR |
Full listing title: Rinnai RE180iN Non-Condensing Natural Gas Tankless Water Heater
| Fuel | Natural GasFull listing title |
|---|---|
| Stated mounting location | RE180iNFull listing title (Rinnai model suffix: i = indoor, e = exterior) |
| Stated maximum flow | up to 6.9 GPMListing text |
Rated from the listing's specs, no buyer reviews yet
What it's made for: a two-bathroom house with one shower running at a time.
Two gas tankless heaters on natural gas too, with about the same flow, closest to it on our rating, each with a dated price.
That's the maximum flow the listing states, and headline flows are usually quoted at a mild temperature rise. Up north in winter, 42 °F water has to climb 63 °F to reach a 105 °F shower, and the flow drops with it. Ask for the flow chart and read that line. Our calculator counts a shower at 2 GPM, so on paper that's two showers and a kitchen tap, less when the water comes in cold.
What it has going for it
15-year warranty. 15 years on the heat exchanger, per the listing. Read what it needs from you: many makers ask for a licensed install and regular flushing to keep it valid.
One at a time, plus the kitchen tap: 6.9 GPM covers that on paper.
Two at once: it depends on your groundwater. With 42 °F water in January, expect the second shower to cool off; the flow chart at a 63 °F rise tells you by how much.
What the Rinnai RE180iN Non-Condensing listing names:
Warranty & support: 15-year warranty on the heat exchanger, as stated in the listing.
That is the maker's promise, not ours. Keep the invoice, register the Rinnai RE180iN Non-Condensing if the maker asks, and read the install conditions: many tankless warranties need a licensed install and regular flushing.
For the Rinnai RE180iN Non-Condensing, the installation manual settles the venting, the gas line and the clearances.
At the price on Sep 30, 2026, each GPM of stated maximum flow works out at about $158.14 (price ÷ stated GPM, our arithmetic). That puts it in the pricier third of the 45 indoor gas tankless heaters we have a price and a stated flow for.
The heater is often the smaller half of the bill: the venting, a gas line that may need upsizing and a licensed installer's day come on top.
The button opens the exact listing (ASIN B0B57PQYLR), where today's price, stock and seller apply. Sizes and variants of the same family often sit at different prices.
Two showers and the dishwasher at once? The MIZUDO 199,000 BTU Natural Gas Indoor (9.2/10) states up to 10.3 GPM.
No easy route for a vent pipe? The Rheem RTG 7.0 GPM Natural Gas Outdoor (7.6/10) mounts on an outside wall, per its listing.
On propane, not natural gas? The Marey 170,000 BTU Propane Indoor (7.6/10) runs on propane.
Our take
What we'd buy the Rinnai RE180iN Non-Condensing for is a 6.9 GPM maximum flow, with a 15-year heat exchanger warranty as a bonus. Only 16 buyers have rated it so far (4.4/5), so treat the score as an early read. The catch with this Rinnai indoor gas tankless heater: no stated temperature hold, while most picks here claim ±1 °F. We'd pick it if you run one shower and the kitchen tap at once, rarely more; otherwise, put it next to the Eccotemp SMARTHOME Natural Gas (6.8 GPM) first.
Old tank out, unit on the wall, vent through the wall or the roof. a licensed pro handles it, and often a permit.
Hot water arrives after the cold already in the pipes, then stays. A trickle from a bathroom tap may not light the burner; open it a bit more.
January water comes in colder, so the same unit gives fewer GPM. Stagger the showers if you sized it tight.
Flush the heat exchanger with a pump and a descaler (the service valves make it an hour's job), and clean the inlet filter. Our flushing and descaling guide has the checklist.
Buyers give it 4.4/5, a strong record, above our ranked picks' 4.3 average. Only 16 reviews so far, and our formula damps averages built on fewer than 50.
Before the Rinnai RE180iN Non-Condensing ships, check your winter flow: 6.9 GPM is a best case, so run your January numbers in our calculator first.
Count the fixtures that run together on a busy morning (our calculator uses 2 GPM a shower, 1.5 for the kitchen), then compare with the maker's chart. Our sizing guide shows how.
A licensed plumber or gas fitter confirms the vent route, the combustion air and a gas line that can deliver its full input. Get that quote before you order; our installation guide lists what they will ask.
15 years are stated on the heat exchanger. Read what it requires: a licensed install, the gas type and regular flushing are the usual conditions.
Hard water scales the heat exchanger. Service valves on the water lines turn the yearly flush into an hour with a bucket and a pump; our flushing and descaling guide shows the routine.
How the Rinnai RE180iN Non-Condensing stacks up against the closest alternative, the Eccotemp SMARTHOME Natural Gas (6.8 GPM).
| Criterion | Rinnai RE180iN Non-Condensing | Eccotemp SMARTHOME Natural Gas, 6.8 GPM |
|---|---|---|
| Our rating | 7.1/10 | 7.1/10 |
| Max flow | 6.9 GPM | 6.8 GPM |
| Gas input | Not stated | 140,000 BTU/h |
| Warranty | 15 years (heat exchanger) | 5 years (heat exchanger) |
| Buyer reviews | 16 · 4.4/5 | 3 · 2.7/5 |
Both score 7.1/10. The Eccotemp SMARTHOME Natural Gas (6.8 GPM) adds a bigger burner (140,000 BTU/h), while the Rinnai RE180iN Non-Condensing brings more flow (6.9 GPM) and a longer stated warranty (15 years).
We rate it 7.1/10 (good). The rating comes from its documented listing alone, as no customer-review record is captured yet.
The listing states a maximum flow of 6.9 GPM. The headline flow is a mild-weather number: with cold winter water coming in, the same unit gives you less. Read the maker's flow chart at your winter rise, or let our flow-rate calculator do the sums.
Yes, the listing says indoor mounting. That means a vent route to the outside, combustion air and a gas line sized for the unit, all as the maker and your local code require. A licensed plumber or gas fitter sorts that out.
Its listing states up to 6.9 GPM and a 15-year heat exchanger warranty. These are the seller's figures, not our measurements: how steady the temperature is in your shower and how it copes with your winter water can't be read from a listing.
Your winter flow: count the fixtures that run together on a busy morning (our calculator uses 2 GPM a shower, 1.5 for the kitchen), then compare with the maker's chart. Our sizing guide shows how. Vent and gas line: a licensed plumber or gas fitter confirms the vent route, the combustion air and a gas line that can deliver its full input. Get that quote before you order; our installation guide lists what they will ask. The warranty terms: 15 years are stated on the heat exchanger. Read what it requires: a licensed install, the gas type and regular flushing are the usual conditions. Flushing: hard water scales the heat exchanger. Service valves on the water lines turn the yearly flush into an hour with a bucket and a pump; our flushing and descaling guide shows the routine.
We link to the exact listing on Amazon, where today's price, stock and seller apply. It is an affiliate link, and it has no effect on the rating.
No, we haven't used it ourselves. Everything on this page comes from its listing and 16 buyer reviews, read line by line and weighed with our published formula.