Propane tankless · APUS

APUS AP-AWH-Q20LPG 140,000 BTU Propane Tankless Water Heater

140,000 BTU/h propane tankless, about 4.8 GPM at a 45°F rise

6.8 GPM max140,000 BTU/h~3.1 GPM at 70°F risePropane

Updated October 2026

The short answer

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

Delivers
140,000 BTU/h input.
Watch for
Gas pipe sizing to confirm.
Suits
One shower at a time in cold climates.
Max flow (maker)
6.8 GPM
Input (maker)
140,000 btu_per_hour_per_foot_per_fahrenheit
Voltage
120 V
Fuel
propane
UEF (maker)
0.81
Connections
1/2" npt
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What it delivers

The APUS AP-AWH-Q20LPG 140,000 BTU Propane Tankless Water Heater is a propane tankless with a 140,000 BTU/h burner and a stated maximum flow of 6.8 GPM. Its listing gives a UEF of 0.81.

Worked out from its input, it delivers roughly 4.8 GPM when the water only has to rise 45°F, and 3.1 GPM at a 70°F winter rise: 2 showers at 2 GPM in summer, 1 shower at 2 GPM in winter. Size it to your fixtures and climate.

At full fire it burns about 1.5 gallons of propane an hour. The gas line has to carry that on top of the furnace, range and dryer; a gas fitter sizes the pipe from its length and the total load.

Non-condensing indoor units run hot exhaust and vent in the maker's listed vent system (often stainless Category III), which costs more than plastic.

Other listed details: connections: 1/2" npt; material: 6.8GPM 140,000BTU; model: AP-AWH-Q20LPG; warranty: 2 Year Manufacturer Warranty.

The listing gives dimensions of 7.09 in (W) x 21.26 in (H) and a weight of 26.9 lb.

Warranty, per the listing: 2 Year Manufacturer Warranty.

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

  • 140,000 BTU/h input
  • Up to 6.8 GPM
  • UEF 0.81

Trade-offs

  • Gas pipe sizing to confirm
  • 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 numberAP-AWH-Q20LPGRetailer
Dimensions (seller)7.09"W x 21.26"HRetailer
Voltage120 VRetailer
Max flow (maker)6.8 GPMRetailer
Input (maker)140,000 btu_per_hour_per_foot_per_fahrenheitRetailer
Product weight26.9 lbRetailer
Warranty2 Year Manufacturer WarrantyRetailer
Material6.8GPM 140,000BTURetailer
UEF (maker)0.81Retailer
FuelpropaneRetailer
Connections1/2" nptRetailer

Rival units at this flow

More gas tankless water heaters rated for similar demand

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

Final verdict

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

Buy this unit

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Prices change often; the button shows today's price.

Each button opens this exact model. We may earn a commission on tracked links; it never changes what we publish. Disclosure

Questions buyers ask

What flow does the APUS AP-AWH-Q20LPG 140,000 BTU Propane Tankless Water Heater give in winter?
From its 140,000 BTU/h input we estimate about 4.8 GPM at a 45°F rise and 3.1 GPM at a 70°F rise, so 2 two-GPM showers 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 APUS AP-AWH-Q20LPG 140,000 BTU Propane Tankless Water Heater need?
At full fire it uses about 135 cubic feet of natural gas an hour or 1.5 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.