AMERICAN HPACO-45 1**+AXST-50T 1** vs GSW WATER HEATERS HPACO-45 1**+AXST-50S 1**: which uses less energy?
At the medium draw pattern the AMERICAN HPACO-45 1**+AXST-50T 1** and the GSW WATER HEATERS HPACO-45 1**+AXST-50S 1** use the same energy, 923 kWh a year each, on the same federal test. Both are filed as an electric tank, so the comparison holds; what separates them is below. Enter your ZIP to price either one on your own rate.
Side by side
Compared within one class only: models filed as an electric tank at the medium draw pattern.
| Figure | AMERICAN HPACO-45 1**+AXST-50T 1** | GSW WATER HEATERS HPACO-45 1**+AXST-50S 1** |
|---|---|---|
| UEF (Uniform Energy Factor) | 3.52 | 3.52 |
| Energy use per year (kWh) | 923 | 923 |
| First hour rating (gal) | 67 | 70 |
| Rated storage volume (gal) | 45 | 46 |
| Installed cost range | $2,998–$4,170 | $3,030–$4,180 |
| ENERGY STAR certified | yes | yes |
| Refrigerant | R-744 (CO2), GWP 1 | R-744 (CO2), GWP 1 |
| On the market since | 2026-02-13 | 2026-02-13 |
What it costs to run
Reliability
Not published: Reliability, failure rates and each model’s actual warranty term.
The registries these figures come from certify energy performance under a federal test; none of them records how long a unit lasts or how often it fails, so this page does not rank the two on reliability.
What is here instead:
- The filed efficiency, capacity and tank size of both models, side by side below.
- Both are ENERGY STAR certified, which requires a manufacturer warranty of at least six years; the actual term for each model is not published.
- Time on the market, as filed with ENERGY STAR: the AMERICAN HPACO-45 1**+AXST-50T 1** since 2026-02-13, the GSW WATER HEATERS HPACO-45 1**+AXST-50S 1** since 2026-02-13. A sale date, not a lifespan.
Which should you pick?
- Pick the AMERICAN HPACO-45 1**+AXST-50T 1** if its price or availability suits you — on energy the two are level.
- Pick the GSW WATER HEATERS HPACO-45 1**+AXST-50S 1** if you need more hot water in your busiest hour: it lists a first hour rating of 70 gallons against 67.
- Neither if your household's busiest hour needs more than 70 gallons of hot water — neither lists more. Check whether a 40-gallon heater is enough.
Each model on its own
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AMERICAN HPACO-45 1**+AXST-50T 1**
Its filed figures, class position and running cost on your ZIP.
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GSW WATER HEATERS HPACO-45 1**+AXST-50S 1**
Its filed figures, class position and running cost on your ZIP.