Ariston ENS30LUB* vs Ruud MR30245 C: which uses less energy?
An asterisk in a model number stands for any character: one filing covers several variants.
At the low draw pattern the Ariston ENS30LUB* uses 2,439 kWh a year and the Ruud MR30245 C 2,550 — 111 kWh (4%) less, about 1,109 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 low draw pattern.
| Figure | Ariston ENS30LUB* | Ruud MR30245 C |
|---|---|---|
| UEF (Uniform Energy Factor) | 0.92 (better) | 0.88 |
| Energy use per year (kWh) | 2,439 (better) | 2,550 |
| First hour rating (gal) | 40 | 37 |
| Rated storage volume (gal) | 28 | 28 |
| Installed cost range NLR REMDB | $1,475–$1,602 | not published |
| CPSC recall naming it CPSC | none on file | none on file |
DOE CCD · 2026-09-19 NLR REMDB · 2026-04-01 CPSC · 2026-09-24
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 above.
- No CPSC recall on file names either model (list checked 2026-09-24).
- The actual warranty term is printed in each model’s documentation, not in any registry.
Which should you pick?
- Pick the Ariston ENS30LUB* if running cost matters most: it uses 111 kWh less a year on the same test.
- Pick the Ruud MR30245 C if it is the one you can get installed sooner or for less — on the filed figures it has no advantage over the Ariston ENS30LUB*.
- Neither if your household's busiest hour needs more than 40 gallons of hot water — neither lists more. Check whether a 30-gallon heater is enough.
Each model on its own
- Ariston ENS30LUB* 2,439 kWh a year
- Ruud MR30245 C 2,550 kWh a year