Ranein RH10K 100,000 BTU Natural Gas Tankless Water Heater

What it delivers

The Ranein RH10K 100,000 BTU Natural Gas Tankless Water Heater is a non-condensing gas tankless with a 100,000 BTU/h burner and a stated maximum flow of 4.3 GPM.

Expect about 2.2 GPM with cold winter water (a 70°F rise) and 3.4 GPM when the inlet is milder (45°F rise); that is 1 shower at 2 GPM in January. Check it against your own fixtures.

The line must deliver about 97 cubic feet of natural gas an hour or about 1.1 gallons of propane an hour when it fires flat out. The requirement calculator adds it up; a licensed fitter confirms the pipe.

Its exhaust runs hot, so the vent must be the material its manual lists, usually stainless; budget for the vent kit.

Listed details: features: LED Display; material: Natural Gas; model: RH10K; warranty: 2 Year Manufacturer.

The listing gives dimensions of 14.17 in (W) x 22.05 in (H).

Warranty, per the listing: 2 Year Manufacturer.

Right unit for this house?

Install it when

One shower at a time in cold climates
Replacing a gas tank heater

Look at another unit when

More than 1 winter shower at once
Homes without a gas line

Strengths and trade-offs

Strengths

100,000 BTU/h input
Up to 4.3 GPM

Trade-offs

Needs a gas line sized for the load
Stainless venting costs more
Needs periodic descaling

Install limits

Figures are the maker's or seller's own. Flow at a rise is our estimate from the input; gas, venting and electrical work needs a licensed professional.

Rated performance

Every figure below comes from the source shown in brackets. Where the maker doesn't state something, we say so instead of estimating.

Model number	RH10K	Retailer
Dimensions (seller)	14.17"W x 22.05"H	Retailer
Features (seller)	LED Display	Retailer
Voltage	120 V AC	Retailer
Max flow (maker)	4.3 GPM	Retailer
Input (maker)	100,000 BTU/h	Retailer
Warranty	2 Year Manufacturer	Retailer
Material	Natural Gas	Retailer
Fuel	propane	Retailer

Rival units at this flow

VEVOR JSQ30-A 100,000 BTU Tankless Water Heater100,000 BTU/h.

GASLAND CG360NG 98,500 BTU Natural Gas Tankless Water Heater98,500 BTU/h, up to 4.0 GPM.

ThermoMate CZ360NG 98,500 BTU Natural Gas Tankless Water Heater98,500 BTU/h, up to 4.0 GPM.

More gas tankless water heaters rated for similar demand

Full gas tankless water heaters spec grid · Every Ranein unit in the catalog

Final verdict

A well-specified non-condensing gas tankless for one shower at a time in cold climates.

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Questions buyers ask

What flow does the Ranein RH10K 100,000 BTU Natural Gas Tankless Water Heater give in winter?

From its 100,000 BTU/h input we estimate about 3.4 GPM at a 45°F rise and 2.2 GPM at a 70°F rise, so 1 two-GPM shower with mild inlet water and 1 in a cold winter. The maker's flow chart for this model is the final word.

What size gas line does the Ranein RH10K 100,000 BTU Natural Gas Tankless Water Heater need?

At full fire it uses about 97 cubic feet of natural gas an hour or 1.1 gallons of propane. The pipe size depends on the length of the run and every other gas appliance on it; the maker's manual and a licensed gas fitter decide it.