Outdoor gas tankless · Westinghouse

Westinghouse HS180A0G-NG 180,000 BTU 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 riseNatural gasOutdoor, no vent pipe

Updated October 2026

The short answer

A sensible 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
natural gas
Venting
outdoor installation
Connections
3/4" npt
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What it delivers

The Westinghouse HS180A0G-NG 180,000 BTU 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.

Worked out from its input, it delivers roughly 6.2 GPM when the water only has to rise 45°F, and 4.0 GPM at a 70°F winter rise: 3 showers at 2 GPM in summer, 1 shower at 2 GPM in winter. Check it against your own fixtures.

Gas load at full fire: about 174 cubic feet of natural gas 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.

As an outdoor model it mounts on an exterior wall and needs no vent pipe; in freezing climates check the maker's freeze protection and cover the connections.

The listing describes its venting as: outdoor installation.

Other listed details: connections: 3/4" npt; model: HS180A0G-NG.

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
  • 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
  • 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 numberHS180A0G-NGRetailer
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
Fuelnatural gasRetailer
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 sensible 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

Is the Westinghouse HS180A0G-NG 180,000 BTU Outdoor Tankless Water Heater big enough for two showers?
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-NG 180,000 BTU Outdoor Tankless Water Heater need?
At full fire it uses about 174 cubic feet of natural gas an hour. 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.