DoesTheMath

Lennox WHES040L45SN240B**** vs Richmond PROPH40 T0 RH120-M: which uses less energy?

At the low draw pattern the Richmond PROPH40 T0 RH120-M uses 802 kWh a year and the Lennox WHES040L45SN240B**** 2,439 — 1,638 kWh (67%) less, about 16,379 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
Lennox WHES040L45SN240B**** Richmond PROPH40 T0 RH120-M
UEF (Uniform Energy Factor) 0.92 2.8 (better)
Energy use per year (kWh) 2,439 802 (better)
First hour rating (gal) 46 45
Rated storage volume (gal) 36 36
Installed cost range $1,591–$1,802 not published
ENERGY STAR certified not matched yes
Refrigerant not filed R-134a, GWP 1430
On the market since not filed 2022-04-21
DOE CCD · 2026-09-19

What it costs to run

Lennox WHES040L45SN240B****: 2,439 kWh a year Richmond PROPH40 T0 RH120-M: 802 kWh a year

Lennox WHES040L45SN240B**** — 2,439 kWh a year Richmond PROPH40 T0 RH120-M — 802 kWh a year

Richmond PROPH40 T0 RH120-M is 1,637 kWh a year lower than Lennox WHES040L45SN240B****.

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 Richmond PROPH40 T0 RH120-M if running cost matters most: it uses 1,638 kWh less a year on the same test.
  • Pick the Lennox WHES040L45SN240B**** if you need more hot water in your busiest hour: it lists a first hour rating of 46 gallons against 45.
  • Neither if your household's busiest hour needs more than 46 gallons of hot water — neither lists more. Check whether a 40-gallon heater is enough.

Each model on its own

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