DoesTheMath

Rheem PROE38 S2 RH93 SB-LO vs VAUGHN ME-40: which uses less energy?

At the low draw pattern the Rheem PROE38 S2 RH93 SB-LO uses 2,413 kWh a year and the VAUGHN ME-40 2,439 — 26 kWh (1%) less, about 262 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.

Filed and computed figures
Rheem PROE38 S2 RH93 SB-LO VAUGHN ME-40
UEF (Uniform Energy Factor) 0.93 (better) 0.92
Energy use per year (kWh) 2,413 (better) 2,439
First hour rating (gal) 42 46
Rated storage volume (gal) 35 37
Installed cost range $1,583–$1,994 $1,605–$1,828
ENERGY STAR certified not matched not matched
DOE CCD · 2026-09-19

What it costs to run

Rheem PROE38 S2 RH93 SB-LO: 2,413 kWh a year VAUGHN ME-40: 2,439 kWh a year

Rheem PROE38 S2 RH93 SB-LO — 2,413 kWh a year VAUGHN ME-40 — 2,439 kWh a year

Rheem PROE38 S2 RH93 SB-LO is 26 kWh a year lower than VAUGHN ME-40.

DOE CCD · 2026-09-19

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Enter your ZIP to price both units on the same rate where you live.

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.
  • The actual warranty term is printed in each model’s documentation, not in any registry.

Which should you pick?

  • Pick the Rheem PROE38 S2 RH93 SB-LO if running cost matters most: it uses 26 kWh less a year on the same test.
  • Pick the VAUGHN ME-40 if you need more hot water in your busiest hour: it lists a first hour rating of 46 gallons against 42.
  • Neither if your household's busiest hour needs more than 46 gallons of hot water — neither lists more. Check whether a 30-gallon heater is enough.

Each model on its own

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