Hot Water List

Gas storage water heaters side by side

The 2 most-searched gas storage models, with the certified figures of each.

These tanks are sold in sizes of 40 to 50 gallons, depending on the model. Starting full, the tank with the most first-hour hot water gives 79 gallons. Among these tanks, the A. O. Smith GPVL-50 2** is the one with that figure. The tank reheats during the hour, so 79 gallons tops the largest tank size here.

Their UEF figures do not compare, since these gas storage models were not all tested on one draw pattern. Not one of these gas storage models is listed as ENERGY STAR certified.

All 2 models here may qualify for at least one rebate program. Each of these gas storage models has figures that other basic models carry too. With the other basic models that carry the same figures, they come to 14 basic models.

Every gas storage model by efficiency and first-hour hot water

Up is more hot water in the first hour of use, starting full. Right is more efficient. A UEF compares only between models tested on the same draw pattern, so the chart shows one pattern at a time, the most common first.

Low draw pattern · 9 models
Gas storage water heaters, low draw pattern: efficiency and first-hour rating (gal) 9 models. UEF axis from 0.54 to 0.57. Highest UEF: 3 models, UEF 0.57. Most hot water in the first hour: 2 models, 50 gal. 3 models UEF 0.572 models 50 gal
Medium draw pattern · 288 models
Gas storage water heaters, medium draw pattern: efficiency and first-hour rating (gal) 288 models. UEF axis from 0.56 to 0.76. Highest UEF: 4 models, UEF 0.75. Most hot water in the first hour: 7 models, 74 gal. 4 models UEF 0.757 models 74 gal
High draw pattern · 434 models
Gas storage water heaters, high draw pattern: efficiency and first-hour rating (gal) 434 models. UEF axis from 0.60 to 0.91. Highest UEF: 12 models, UEF 0.90. Most hot water in the first hour: 5 models, 119 gal. 12 models UEF 0.905 models 119 gal

32 models with no draw pattern listed are on the full list, not on the chart.

Compare every water heater type by efficiency

Certified figures

In order of size, smallest first, then UEF, highest first.

Gas storage water heaters: certified figures side by side
FigureA. O. Smith GPVL-40 2**A. O. Smith GPVL-50 2**
Size (gal)4050
Storage volume (gal)3849
UEF0.670.72
Draw patternMediumHigh
First-hour rating (gal)7379
Recovery efficiency79%80%
ENERGY STAR——
Listed models34
Rebate programs (may qualify)22
Also listed as6 basic models6 basic models

UEF is the uniform energy factor. A UEF compares only between models with the same draw pattern. A range means the listed models differ. A dash means no such figure, or not listed as ENERGY STAR certified.

Also listed as

A. O. Smith GPVL-40 2**

A. O. Smith GPVL-50 2**

Each carries every figure in its column.

Every gas storage water heater with its certified figures

Updated Oct 26, 2026 · Methodology

Not covered

  • Price, warranty, and installation.
  • Models searched for less often. Each one is on the full list.