Lennox WHHP050T45MD240S**** vs STEALTH ACIQ-50G-HP-WH: which uses less energy?
At the medium draw pattern the Lennox WHHP050T45MD240S**** uses 848 kWh a year and the STEALTH ACIQ-50G-HP-WH 866 — 18 kWh (2%) less, about 181 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 | Lennox WHHP050T45MD240S**** | STEALTH ACIQ-50G-HP-WH |
|---|---|---|
| UEF (Uniform Energy Factor) | 3.83 (better) | 3.75 |
| Energy use per year (kWh) | 848 (better) | 866 |
| First hour rating (gal) | 69 | 69 |
| Rated storage volume (gal) | 45 | 47 |
| Installed cost range | $3,033–$4,480 | $3,089–$4,419 |
| ENERGY STAR certified | yes | yes |
| Sound level (dB) | not filed | 49 |
| Refrigerant | R-513A, GWP 630 | R-134a, GWP 1430 |
| On the market since | 2025-12-01 | 2024-05-30 |
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 Lennox WHHP050T45MD240S**** since 2025-12-01, the STEALTH ACIQ-50G-HP-WH since 2024-05-30. A sale date, not a lifespan.
Which should you pick?
- Pick the Lennox WHHP050T45MD240S**** if running cost matters most: it uses 18 kWh less a year on the same test.
- Pick the STEALTH ACIQ-50G-HP-WH if it is the one you can get installed sooner or for less — on the filed figures it has no advantage over the Lennox WHHP050T45MD240S****.
- 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
-
Lennox WHHP050T45MD240S****
Its filed figures, class position and running cost on your ZIP.
-
STEALTH ACIQ-50G-HP-WH
Its filed figures, class position and running cost on your ZIP.