What it delivers
The Westinghouse AMZ-HS120A1G-LP 120,000 BTU Propane Outdoor Tankless Water Heater is an outdoor gas tankless with a 120,000 BTU/h burner and a stated maximum flow of 5.1 GPM.
Worked out from its input, it delivers roughly 4.1 GPM when the water only has to rise 45°F, and 2.6 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 1.3 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.
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.
Other listed details: material: 5.1 GPM, Outdoor Installation; model: AMZ-HS120A1G-LP.
The listing gives dimensions of 15.5 in (W) x 23.9 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
- 120,000 BTU/h input
- Up to 5.1 GPM
- No vent pipe
Trade-offs
- Needs a gas line sized for the load
- Needs freeze protection outdoors
- 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 | AMZ-HS120A1G-LP | Retailer |
|---|---|---|
| Dimensions (seller) | 15.5"W x 23.9"H | Retailer |
| Voltage | 120 V AC | Retailer |
| Max flow (maker) | 5.1 GPM | Retailer |
| Input (maker) | 120,000 BTU/h | Retailer |
| Material | 5.1 GPM, Outdoor Installation | Retailer |
| Fuel | propane | Retailer |
Rival units at this flow
More gas tankless water heaters rated for similar demand
- Westinghouse AMZ-HS120A1G-NG 120,000 BTU Natural Gas Outdoor Tankless Water Heater
- APUS AP-AWH-W26LPG 190,000 BTU Propane Outdoor Tankless Water Heater
- APUS AP-AWH-W26NG 190,000 BTU Natural Gas Outdoor Tankless Water Heater
- VancEpic V-RHO19K-NG 190,000 BTU Natural Gas Outdoor Tankless Water Heater
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
Our links open this exact model's product page. Prices and stock change; check what's included before you order.
Each button opens this exact model. We may earn a commission on tracked links; it never changes what we publish. Disclosure