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A. O. Smith GUC-50 4**

A. O. Smith GUC-50 4** is in the DOE listing as of Oct 26, 2026.

It has a labeled size of 50 gallons, a certified storage volume of 48 gallons, a certified UEF of 0.61, and a certified first-hour rating of 84 gallons of hot water.

Its advertised UEF of 0.61 from A. O. Smith matches the certified 0.61 (Read Oct 5, 2026).

  • Gas storage water heater
  • 4 listed models

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

Storage volume
48gallons
UEF
0.61Uniform energy factor
First-hour rating
84gallonsHot water in the first hour
See it among every gas storage model

Advertised and certified figures

A. O. Smith GUC-50 4**: advertised and certified
A. O. Smith GUC-50 4**: advertised and certified Size: advertised 50 gal, certified 48 gal (advertised nominal size, certified storage volume). Size: advertised 48 gal, certified 48 gal (certified storage volume). UEF: advertised 0.61, certified 0.61. UEF: advertised 0.61, certified 0.61 (advertised up to). Size · advertised nominal size, certified storage volume Advertised 50 gal Certified 48 gal Size · certified storage volume Advertised 48 gal Certified 48 gal UEF Advertised 0.61 Certified 0.61 UEF · advertised up to Advertised 0.61 Certified 0.61
FigureAdvertisedCertifiedAdvertiserRead
Size 50 gal, nominal size 48 gal storage volume A. O. Smith Read Oct 5, 2026
Size 48 gal 48 gal storage volume A. O. Smith Read Oct 5, 2026
UEF 0.61 0.61 A. O. Smith Read Oct 5, 2026
UEF up to 0.61 0.61 A. O. Smith Read Oct 5, 2026
First-hour rating 84 gal 84 gal A. O. Smith Read Oct 5, 2026

Certified figures by listed model

Model numberStorage volume (gal)UEFFirst-hour rating (gal)Recovery efficiencyDraw pattern
G6N-UT5040NVR 4**480.618477%High
GUC-50 4**480.618477%High
HUC-50 4**480.618477%High
XUC 50 4**480.618477%High

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

It holds 48 gallons in the test, 2 gallons less than its 50-gallon sold size. Starting full, it gives 84 gallons of hot water in its first hour of use. Its tank holds 48 gallons, so reheating adds 36 gallons during the first hour. Of 763 gas storage models, 209 give more hot water in the first hour. The median gas storage model gives 78 gallons in its first hour.

As of Oct 26, 2026, it was not listed as ENERGY STAR certified. In tests, 61% of the energy it uses ends up as hot water (UEF 0.61). Its test ran at the high level of daily hot water use. Of 434 gas storage models with the same draw pattern, 419 have a higher UEF. For its type and draw pattern, the UEF runs from 0.61 to 0.90. The water took in 77% of the energy used to reheat it (its recovery efficiency).

All 4 of its model numbers carry the same certified figures. Its test figures match those of 3 other basic models. The American, RELIANCE WATER HEATERS, and State 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.