Hot Water List
Menu

Rheem 88H40*

Rheem 88H40* is in the DOE listing as of Oct 26, 2026.

It has a labeled size of 40 gallons, a certified storage volume of 36 gallons, a certified UEF of 0.81, and a certified first-hour rating of 50 gallons of hot water.

Its advertised UEF of 0.81 from Rheem matches the certified 0.81 (Read Oct 4, 2026).

  • Tabletop water heater
  • 4 listed models

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

Storage volume
36gallons
UEF
0.81Uniform energy factor
First-hour rating
50gallonsHot water in the first hour
See it among every electric storage model

Advertised and certified figures

Rheem 88H40*: advertised and certified
Rheem 88H40*: advertised and certified Size: advertised 40 gal, certified 36 gal (advertised nominal size, certified storage volume). UEF: advertised 0.81, certified 0.81. First-hour rating: advertised 50 gal, certified 50 gal. Size · advertised nominal size, certified storage volume Advertised 40 gal Certified 36 gal UEF Advertised 0.81 Certified 0.81 First-hour rating Advertised 50 gal Certified 50 gal
FigureAdvertisedCertifiedAdvertiserRead
Size 40 gal, nominal size 36 gal storage volume Rheem Read Oct 4, 2026
Size 40 gal, nominal size 36 gal storage volume The Home Depot Archived copy, Sep 18, 2025
UEF 0.81 0.81 Rheem Read Oct 4, 2026
UEF 0.81 0.81 The Home Depot Archived copy, Sep 18, 2025
First-hour rating 50 gal 50 gal Rheem Read Oct 4, 2026
First-hour rating 50 gal 50 gal The Home Depot Archived copy, Sep 18, 2025

Certified figures by listed model

Model numberStorage volume (gal)UEFFirst-hour rating (gal)Recovery efficiencyDraw pattern
1PZ87360.815098%Low
88H40*360.815098%Low
88H40DGR360.815098%Low
XE40H06TT45U0360.815098%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. It delivers 50 gallons of hot water in the test's first hour. Reheating lets it give 14 gallons beyond the 36 gallons in its tank. Among 7 tabletop models, 4 have a higher first-hour rating. Among tabletop models, the median first-hour rating is 55 gallons.

In tests, 81% of the energy it uses ends up as hot water (UEF 0.81). In the test, daily hot water use was set to low (its draw pattern). No other tabletop model among the 3 on its draw pattern has a higher UEF. Its UEF is the median for its type and draw pattern. When it reheats water in the test, 98% of the energy it uses ends up in the water.

It is sold under 4 model numbers in all. All of its test figures are shared by 2 other basic models. The Richmond and Ruud brands list one or more of them.

Also listed as

They carry every figure in the table above.

Updated Oct 26, 2026 · Methodology

Not covered

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