Product images: Amazon listings
Written from the listing's specs, not from our own use · How we rate
On paper, the Rinnai RE180iP Non-Condensing gets the important things right: an 8.5 GPM maximum flow and a 15-year heat exchanger warranty. It makes most sense for a two-bathroom house with one shower running at a time; we rate it 7.1/10 from its listing.
These are sold as variants of one listing family. Each variant has its own page.
| Brand | Rinnai |
|---|---|
| Category | Gas tankless water heaters |
| Fuel | Propane |
| Stated mounting location | Indoor |
| Stated maximum flow | 8.5 GPM |
| Wi-Fi | With an optional module |
| Stated warranty | 15 years on the heat exchanger |
| ASIN | B0B57MDSCS |
Full listing title: Rinnai RE180iP Non-Condensing Propane Tankless Water Heater
| Fuel | PropaneFull listing title |
|---|---|
| Stated mounting location | RE180iPFull listing title (Rinnai model suffix: i = indoor, e = exterior) |
| Stated maximum flow | up to 8.5 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 propane 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.
Two at once: up to 8.5 GPM, and our calculator counts a shower at 2 GPM, so that's two showers and a tap on paper. The maker's flow chart at a 63 °F rise tells you how much of that is left in January.
One at a time: a smaller unit covers that for less money.
What the Rinnai RE180iP 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 RE180iP Non-Condensing if the maker asks, and read the install conditions: many tankless warranties need a licensed install and regular flushing.
For the Rinnai RE180iP 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 $128.37 (price ÷ stated GPM, our arithmetic). That puts it around the middle 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 B0B57MDSCS), 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 Rinnai RU199iN Condensing (7.8/10) states up to 11 GPM.
Want the high-efficiency kind? The Rheem RTGH 9.5 GPM Propane Indoor (7.8/10) is a condensing unit, per its listing.
On natural gas, not propane? The Ranein 190,000 BTU Natural Gas Indoor (7.9/10) runs on natural gas.
Our take
What we'd buy the Rinnai RE180iP Non-Condensing for is an 8.5 GPM maximum flow, with a 15-year heat exchanger warranty as a bonus. No buyer reviews yet, so this Rinnai indoor gas tankless heater has to win you over on paper. The catch with the Rinnai: 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.
Before the Rinnai RE180iP Non-Condensing ships, check your winter flow: 8.5 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 RE180iP Non-Condensing stacks up against the closest alternative, the Eccotemp SMARTHOME Natural Gas (6.8 GPM).
| Criterion | Rinnai RE180iP Non-Condensing | Eccotemp SMARTHOME Natural Gas, 6.8 GPM |
|---|---|---|
| Our rating | 7.1/10 | 7.1/10 |
| Max flow | 8.5 GPM | 6.8 GPM |
| Gas input | Not stated | 140,000 BTU/h |
| Warranty | 15 years (heat exchanger) | 5 years (heat exchanger) |
| Buyer reviews | None captured | 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 RE180iP Non-Condensing brings more flow (8.5 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 8.5 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 8.5 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, read line by line and weighed with our published formula.