
Ranein Condensing Propane, 5.1 GPM
7.4Good · out of 10$559 Price on Sep 30, 2026 · may have changed- Stated: 5.1 GPM · 120,000 BTU/h · 120 V
- Gas tankless water heaters

Product images: Amazon listings
Written from the listing's specs, not from our own use · How we rate
If you're after a 5.1 GPM maximum flow, the Ranein Condensing Propane (5.1 GPM) delivers, with condensing efficiency and a ±1 °F temperature hold on top. It makes most sense for a cabin, a garage apartment or an in-law suite; we rate it 7.4/10 from its listing.
| Brand | Ranein |
|---|---|
| Category | Gas tankless water heaters |
| Fuel | Propane |
| Stated maximum flow | 5.1 GPM |
| Stated gas input | 120,000 BTU/h |
| Stated voltage | 120 V |
| Condensing design | Stated in the listing title |
| Temperature range | 95 to 149 °F |
| Temperature hold | ±1 °F, per the listing |
| Freeze protection | Stated in the listing |
| ASIN | B0GZVV4KXN |
Full listing title: Ranein Condensing Propane Tankless Water Heater, 5.1 GPM, 120,000 BTU
| Fuel | PropaneFull listing title |
|---|---|
| Stated maximum flow | 5.1 GPMFull listing title |
| Stated gas input | 120,000 BTUFull listing title |
| Stated voltage | 120VListing text |
| Condensing design | CondensingFull listing title |
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. Counting 2 GPM per shower, as our calculator does, that's one shower and a sink at a time, maybe two showers where the water comes in warm.
What it has going for it
Condensing. A second heat exchanger pulls heat out of the exhaust before it leaves, so more of the gas you pay for ends up in the water. The exhaust runs cool enough for plastic vent pipe, and the condensate needs a drain.
±1 °F hold. The burner adjusts as the flow changes, so the shower stays where you set it when somebody opens the kitchen tap. On paper, at least: that is the seller's claim.
Propane: that's what the listing names. A propane unit runs off a tank outside, so the tank size and the regulator are part of the plan.
Natural gas: it's a different set of gas jets and pressures. Only the maker's conversion kit, if there is one, and a licensed gas fitter can switch it; ask before you order.
The seller states, word for word, in the Ranein Condensing Propane (5.1 GPM) listing:
Set temperature from 95°F to 149°F at ±1°F precision via the LED touchscreen.
An integrated 114W anti-freeze heater activates automatically below 42.8°F to protect internal components in cold winters.
Standard 3/4" NPT connections and 120V plug-in power.
The seller's claims, quoted as written; we haven't measured any of it. The flow at your winter rise is in the maker's chart, not in the bullet points.

What the Ranein Condensing Propane (5.1 GPM) listing names:
For the Ranein Condensing Propane (5.1 GPM), 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 $109.61 (price ÷ stated GPM, our arithmetic). That puts it in the pricier third of the 10 gas tankless heaters we have a price and a stated flow for.
Count the install in the budget: vent pipe, possibly a 3/4" gas line, and a licensed plumber or gas fitter.
The button opens the exact listing (ASIN B0GZVV4KXN), where today's price, stock and seller apply.

Two showers and the dishwasher at once? The Rheem RTG 8.4 GPM Propane Outdoor (7.5/10) states up to 8.4 GPM.
On natural gas, not propane? The ThermoMate Condensing Natural Gas (7.7/10) runs on natural gas.
Our take
What we'd buy the Ranein Condensing Propane (5.1 GPM) for is a 5.1 GPM maximum flow, with condensing efficiency as a bonus. No buyer reviews yet, so this Ranein gas tankless heater has to win you over on paper. The catch with the Ranein: no word on the warranty. We'd pick it if you care about the gas bill as much as the hot water; otherwise, put it next to the GASLAND BE158B Propane (1.58 GPM) first.
Old tank out, unit on the wall, vent through the wall or the roof. Plan the gas line for 120,000 BTU/h; a licensed pro handles it, and often a permit.
Hot water arrives after the cold already in the pipes, then stays (within ±1 °F, per the listing). 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), check the condensate drain and the neutralizer, and clean the inlet filter. Our flushing and descaling guide has the checklist.
Before the Ranein Condensing Propane (5.1 GPM) ships, check your gas line: 120,000 BTU/h is a lot of gas at once, so ask your plumber whether the existing line can feed it.
5.1 GPM is the headline. In a northern January the water comes in near 42 °F, so a 105 °F shower needs a 63 °F rise and the real flow drops. Our flow-rate calculator runs the numbers for your house.
Ask the plumber to check the gas line size and the meter against the heater's input, and to quote the vent route at the same visit. Our install cost guide shows what that usually adds.
A condensing unit drips acidic water that needs a drain, often through a neutralizer. Our condensing guide explains the extra parts.
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 Ranein Condensing Propane (5.1 GPM) stacks up against the closest alternative, the GASLAND BE158B Propane (1.58 GPM).
| Criterion | Ranein Condensing Propane, 5.1 GPM | GASLAND BE158B Propane, 1.58 GPM |
|---|---|---|
| Our rating | 7.4/10 | 7.4/10 |
| Max flow | 5.1 GPM | 1.58 GPM |
| Gas input | 120,000 BTU/h | Not stated |
| Efficiency | Condensing | Not stated |
| Temperature hold | ±1 °F stated | Not stated |
Both score 7.4/10. The Ranein Condensing Propane (5.1 GPM) brings more flow (5.1 GPM) and a bigger burner (120,000 BTU/h), so it has the edge on paper.
We rate it 7.4/10 (good). The rating comes from its documented listing alone, as no customer-review record is captured yet.
The listing states a maximum flow of 5.1 GPM and a gas input of 120,000 BTU/h on 120 V. 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.
Its listing states up to 5.1 GPM, a condensing heat exchanger, temperature held within ±1 °F and freeze protection. 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: 5.1 GPM is the headline. In a northern January the water comes in near 42 °F, so a 105 °F shower needs a 63 °F rise and the real flow drops. Our flow-rate calculator runs the numbers for your house. Vent and gas line: ask the plumber to check the gas line size and the meter against the heater's input, and to quote the vent route at the same visit. Our install cost guide shows what that usually adds. The condensate: a condensing unit drips acidic water that needs a drain, often through a neutralizer. Our condensing guide explains the extra parts. 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.