FRIEDRICH PROPH50 T2 RH375-SO vs Lennox WHHP050T45MD240S****: which uses less energy?
At the medium draw pattern the FRIEDRICH PROPH50 T2 RH375-SO uses 837 kWh a year and the Lennox WHHP050T45MD240S**** 848 — 11 kWh (1%) less, about 109 kWh over ten years. Both are filed as an electric tank, so the comparison holds. Enter your ZIP below to price the difference.
Side by side
Compared within one class only: models filed as an electric tank at the medium draw pattern.
| Figure | FRIEDRICH PROPH50 T2 RH375-SO | Lennox WHHP050T45MD240S**** |
|---|---|---|
| UEF (Uniform Energy Factor) | 3.88 (better) | 3.83 |
| Energy use per year (kWh) | 837 (better) | 848 |
| First hour rating (gal) | 67 | 69 |
| Rated storage volume (gal) | 45 | 45 |
| Installed cost range | $3,039–$4,530 | $3,033–$4,480 |
| ENERGY STAR certified | yes | yes |
| Refrigerant | R-134a, GWP 1430 | R-513A, GWP 630 |
| On the market since | 2024-06-24 | 2025-12-01 |
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 FRIEDRICH PROPH50 T2 RH375-SO since 2024-06-24, the Lennox WHHP050T45MD240S**** since 2025-12-01. A sale date, not a lifespan.
Which should you pick?
- Pick the FRIEDRICH PROPH50 T2 RH375-SO if running cost matters most: it uses 11 kWh less a year on the same test.
- Pick the Lennox WHHP050T45MD240S**** if you need more hot water in your busiest hour: it lists a first hour rating of 69 gallons against 67.
- Neither if your household's busiest hour needs more than 69 gallons of hot water — neither lists more. Check whether a 40-gallon heater is enough.
Each model on its own
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FRIEDRICH PROPH50 T2 RH375-SO
Its filed figures, class position and running cost on your ZIP.
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Lennox WHHP050T45MD240S****
Its filed figures, class position and running cost on your ZIP.