Hot Water List
Menu

A. O. Smith GCB-30R 4**

A. O. Smith GCB-30R 4** is in the DOE listing as of Oct 26, 2026.

It has a labeled size of 30 gallons, a certified storage volume of 29 gallons, a certified UEF of 0.60, and a certified first-hour rating of 62 gallons of hot water.

Its advertised UEF of 0.60 from A. O. Smith matches the certified 0.60 (Read Oct 4, 2026).

  • Gas storage water heater
  • 3 listed models

Not listed as ENERGY STAR certified on Oct 26, 2026.

Storage volume
29gallons
UEF
0.60Uniform energy factor
First-hour rating
62gallonsHot water in the first hour
See it among every gas storage model

Advertised and certified figures

A. O. Smith GCB-30R 4**: advertised and certified
A. O. Smith GCB-30R 4**: advertised and certified Size: advertised 30 gal, certified 29 gal (advertised nominal size, certified storage volume). Size: advertised 29 gal, certified 29 gal (certified storage volume). UEF: advertised 0.60, certified 0.60. UEF: advertised 0.60, certified 0.60 (advertised up to). Size · advertised nominal size, certified storage volume Advertised 30 gal Certified 29 gal Size · certified storage volume Advertised 29 gal Certified 29 gal UEF Advertised 0.60 Certified 0.60 UEF · advertised up to Advertised 0.60 Certified 0.60
FigureAdvertisedCertifiedAdvertiserRead
Size 30 gal, nominal size 29 gal storage volume A. O. Smith Read Oct 4, 2026
Size 29 gal 29 gal storage volume A. O. Smith Read Oct 4, 2026
UEF 0.60 0.60 A. O. Smith Read Oct 4, 2026
UEF up to 0.60 0.60 A. O. Smith Read Oct 4, 2026
First-hour rating 62 gal 62 gal A. O. Smith Read Oct 4, 2026

Certified figures by listed model

Model numberStorage volume (gal)UEFFirst-hour rating (gal)Recovery efficiencyDraw pattern
G6-T3032NVRB 4**290.606274%Medium
GCB-30R 4**290.606274%Medium
GCB-30R 4*1290.606274%Medium

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

It holds 29 gallons in the test, 1 gallon less than its 30-gallon sold size. Over one hour from a full tank, it gave 62 gallons in the test (its first-hour rating). That is 33 gallons more than its tank holds, since it reheats during the hour. Among 763 gas storage models, 671 have a higher first-hour rating. Among gas storage models, the median first-hour rating is 78 gallons.

It was not listed as ENERGY STAR certified on Oct 26, 2026. In tests, 60% of the energy went to hot water, so its UEF is 0.60. The daily hot water use in the test, called its draw pattern, was medium. Of 288 gas storage models with the same draw pattern, 88 have a higher UEF and 103 a lower one. For its type and draw pattern, its UEF sits at the median. When it reheats water in the test, 74% of the energy it uses ends up in the water.

It is sold as G6-T3032NVRB 4**, GCB-30R 4**, and GCB-30R 4*1. All of its test figures are shared by 5 other basic models. They are listed under 5 other brands, one each.

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.