What it delivers
The MIZUDO HW180A0W-NG 180,000 BTU Natural Gas Tankless Water Heater is a non-condensing gas tankless with a 180,000 BTU/h burner and a stated maximum flow of 7.9 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. Run your house through the planner.
The line must deliver about 174 cubic feet of natural gas 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.
The listing describes its venting as: direct-vent.
Listed details: connectivity: WiFi; material: 7.9 GPM, 180,000 BTU, Indoor; model: HW180A0W-NG; warranty: 2-year full machine warranty, 5-year heat exchanger warranty.
The listing gives dimensions of 16.3 in (W) x 25 in (H) and a weight of 39.6 lb.
Warranty, per the listing: 2-year full machine warranty, 5-year heat exchanger warranty.
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 7.9 GPM
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 number | HW180A0W-NG | Retailer |
|---|---|---|
| Dimensions (seller) | 16.3"W x 25"H | Retailer |
| Voltage | 120 V | Retailer |
| Max flow (maker) | 7.9 GPM | Retailer |
| Input (maker) | 180,000 btu_per_hour_per_foot_per_fahrenheit | Retailer |
| Product weight | 39.6 lb | Retailer |
| Material | 7.9 GPM, 180,000 BTU, Indoor | Retailer |
| Warranty | 2-year full machine warranty, 5-year heat exchanger warranty | Retailer |
| Fuel | natural gas | Retailer |
| Venting | direct-vent | Retailer |
| Connectivity | WiFi | Retailer |
Rival units at this flow
More gas tankless water heaters rated for similar demand
- Rheem RTG-70DVLN-3 160,000 BTU Natural Gas Tankless Water Heater
- Westinghouse HW180A0G-NG 180,000 BTU Tankless Water Heater
- MIZUDO WCIU-HW199A1G-NG-M0 199,000 BTU Natural Gas Tankless Water Heater
- A. O. Smith ATI-540P-N 199,000 BTU Natural Gas Tankless Water Heater
Full gas tankless water heaters spec grid · Every MIZUDO unit in the catalog
Final verdict
A well-specified non-condensing gas tankless for one shower at a time in cold climates.
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