Orbek HW100 100,000 BTU Propane Tankless Water Heater: 100,000 BTU/h

What it delivers

The Orbek HW100 100,000 BTU Propane Tankless Water Heater is a propane tankless with a 100,000 BTU/h burner and a stated maximum flow of 4.3 GPM.

Worked out from its input, it delivers roughly 3.4 GPM when the water only has to rise 45°F, and 2.2 GPM at a 70°F winter rise: 1 shower at 2 GPM in summer, 1 shower at 2 GPM in winter. Check it against your own fixtures.

The line must deliver 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.

Other listed details: material: Propane Gas; model: HW100.

The listing gives dimensions of 13 in (W) x 20.5 in (H).

Right unit for this house?

Install it when

One shower at a time in cold climates
Propane homes
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

Gas line may need upsizing
Stainless venting costs more
Scale builds up without flushing

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	HW100	Retailer
Dimensions (seller)	13"W x 20.5"H	Retailer
Voltage	120 V AC	Retailer
Max flow (maker)	4.3 GPM	Retailer
Input (maker)	100,000 BTU/h	Retailer
Material	Propane Gas	Retailer
Fuel	Propane	Retailer

Rival units at this flow

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

ThermoMate CZ360LP 98,500 BTU Propane Tankless Water Heater98,500 BTU/h, up to 4.0 GPM.

Camplux CA422 102,000 BTU Propane Tankless Water Heater102,000 BTU/h, up to 4.2 GPM.

More gas tankless water heaters rated for similar demand

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

Final verdict

A sensible propane tankless for one shower at a time in cold climates.

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Questions buyers ask

What flow does the Orbek HW100 100,000 BTU Propane 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 Orbek HW100 100,000 BTU Propane 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.