Outdoor gas tankless · Westinghouse

Westinghouse HS180A0G-LP 180,000 BTU Propane Outdoor Tankless Water Heater

180,000 BTU/h outdoor gas tankless, about 6.2 GPM at a 45°F rise

8.1 GPM max180,000 BTU/h~4.0 GPM at 70°F risePropaneOutdoor, no vent pipe

Updated October 2026

The short answer

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

Delivers
180,000 BTU/h input.
Watch for
Gas pipe sizing to confirm.
Suits
One shower at a time in cold climates.
Max flow (maker)
8.1 GPM
Input (maker)
180,000 BTU/h
Voltage
120 V
Fuel
propane
Venting
outdoor installation
Connections
3/4" npt
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What it delivers

The Westinghouse HS180A0G-LP 180,000 BTU Propane Outdoor Tankless Water Heater is an outdoor gas tankless with a 180,000 BTU/h burner and a stated maximum flow of 8.1 GPM.

Expect about 4.0 GPM with cold winter water (a 70°F rise) and 6.2 GPM when the inlet is milder (45°F rise); that is 1 shower at 2 GPM in January. Check it against your own fixtures.

Gas load at full fire: about 2.0 gallons of propane an hour. An older half-inch line that already feeds a furnace often can't spare that, so have a gas fitter check the pipe size and run.

Outdoor units vent straight out of the cabinet, which saves the vent run and the wall penetration; plan for freeze protection and a pipe cover where winters bite.

The listing describes its venting as: outdoor installation.

Listed details: connections: 3/4" npt; model: HS180A0G-LP.

The listing gives dimensions of 17.1 in (W) x 26.8 in (H) and a weight of 42 lb.

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

  • 180,000 BTU/h input
  • Up to 8.1 GPM
  • No vent pipe

Trade-offs

  • Gas pipe sizing to confirm
  • Needs freeze protection outdoors
  • Annual flushing on hard water

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 numberHS180A0G-LPRetailer
Dimensions (seller)17.1"W x 26.8"HRetailer
Voltage120 VRetailer
Max flow (maker)8.1 GPMRetailer
Input (maker)180,000 BTU/hRetailer
Product weight42 lbRetailer
FuelpropaneRetailer
Ventingoutdoor installationRetailer
Connections3/4" nptRetailer

Rival units at this flow

More gas tankless water heaters rated for similar demand

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

Final verdict

A well-specified outdoor gas 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

How many showers can the Westinghouse HS180A0G-LP 180,000 BTU Propane Outdoor Tankless Water Heater run at once?
From its 180,000 BTU/h input we estimate about 6.2 GPM at a 45°F rise and 4.0 GPM at a 70°F rise, so 3 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 Westinghouse HS180A0G-LP 180,000 BTU Propane Outdoor Tankless Water Heater need?
At full fire it uses about 174 cubic feet of natural gas an hour or 2.0 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.