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Lennox WHES040L45TN240S****

Lennox WHES040L45TN240S**** is in the DOE listing as of Oct 19, 2026.

  • Electric storage water heater
  • 1 listed model

ENERGY STAR certification does not cover this type of water heater.

Its figures are also listed under AMERICAN STANDARD WATER HEATERS ENS40LU-*.

Storage volume
36gallons
UEF
0.91Uniform energy factor
First-hour rating
41gallonsHot water in the first hour
See it among every electric storage model

Advertised and certified figures

Lennox WHES040L45TN240S****: advertised and certified
Lennox WHES040L45TN240S****: advertised and certified Size: advertised 40 gal, certified 36 gal (advertised nominal size, certified storage volume). UEF: advertised 0.91, certified 0.91. First-hour rating: advertised 41 gal, certified 41 gal. Size · advertised nominal size, certified storage volume Advertised 40 gal Certified 36 gal UEF Advertised 0.91 Certified 0.91 First-hour rating Advertised 41 gal Certified 41 gal
FigureAdvertisedCertifiedAdvertiserRead
Size 40 gal, nominal size 36 gal storage volume Lennox Read Oct 5, 2026
UEF 0.91 0.91 Lennox Read Oct 5, 2026
First-hour rating 41 gal 41 gal Lennox Read Oct 5, 2026

Certified figures by listed model

Model numberStorage volume (gal)UEFFirst-hour rating (gal)Recovery efficiencyDraw pattern
WHES040L45TN240S****360.914198%Low

UEF is the uniform energy factor. A dash means the model has no such figure.

It holds 36 gallons in the test, 4 gallons less than its 40-gallon sold size. Starting full, it gives 41 gallons of hot water in its first hour of use. Reheating lets it give 5 gallons beyond the 36 gallons in its tank. Among 477 electric storage models, 429 have a higher first-hour rating. Among electric storage models, the median first-hour rating is 55 gallons.

In the test, 9% of its energy does not reach the hot water (UEF 0.91). Its test simulated a day of low hot water use (its draw pattern). Of 157 electric storage models with the same draw pattern, 81 have a higher UEF and 42 a lower one. A UEF of 0.92 is the median for its type and draw pattern. Of the energy spent to reheat water, 98% goes into it (its recovery efficiency).

There are 2 more basic models with the same test figures. Those basic models are sold with AMERICAN STANDARD WATER HEATERS and Ariston as their brand names. For the full group, see the AMERICAN STANDARD WATER HEATERS ENS40LU-*.

Also listed as

They carry every figure in the table above.

Updated Oct 19, 2026 · Methodology

Not covered

  • Changes to an advertised figure after the date beside it.