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A. O. Smith ENSB-30 1**

A. O. Smith ENSB-30 1** is in the DOE listing as of Oct 26, 2026.

It has a labeled size of 30 gallons, a certified storage volume of 27 gallons, a certified UEF of 0.91, and a certified first-hour rating of 50 gallons of hot water.

Its advertised UEF of 0.91 from A. O. Smith matches the certified 0.91 (Read Oct 5, 2026).

  • Electric storage water heater
  • 3 listed models

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

Storage volume
27gallons
UEF
0.91Uniform energy factor
First-hour rating
50gallonsHot water in the first hour
See it among every electric storage model

Advertised and certified figures

A. O. Smith ENSB-30 1**: advertised and certified
A. O. Smith ENSB-30 1**: advertised and certified Size: advertised 30 gal, certified 27 gal (advertised nominal size, certified storage volume). Size: advertised 27 gal, certified 27 gal (certified storage volume). UEF: advertised 0.91, certified 0.91. First-hour rating: advertised 50 gal, certified 50 gal. Size · advertised nominal size, certified storage volume Advertised 30 gal Certified 27 gal Size · certified storage volume Advertised 27 gal Certified 27 gal UEF Advertised 0.91 Certified 0.91 First-hour rating Advertised 50 gal Certified 50 gal
FigureAdvertisedCertifiedAdvertiserRead
Size 30 gal, nominal size 27 gal storage volume A. O. Smith Read Oct 5, 2026
Size 27 gal 27 gal storage volume A. O. Smith Read Oct 5, 2026
UEF 0.91 0.91 A. O. Smith Read Oct 5, 2026
First-hour rating 50 gal 50 gal A. O. Smith Read Oct 5, 2026

Certified figures by listed model

Model numberStorage volume (gal)UEFFirst-hour rating (gal)Recovery efficiencyDraw pattern
E6-30R45DVB 1**270.915098%Low
ENSB-30 1**270.915098%Low
PNSB-30 1**270.915098%Low

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

It holds 27 gallons in the test, 3 gallons less than its 30-gallon sold size. Over one hour from a full tank, it gave 50 gallons in the test (its first-hour rating). Its tank holds 27 gallons, so reheating adds 23 gallons during the first hour. Of 477 electric storage models, 321 give more hot water in the first hour. The median electric storage model gives 55 gallons in the first hour of the test.

In tests, 91% of the energy it uses ends up as hot water (UEF 0.91). In the test, daily hot water use was set to low (its draw pattern). Among 157 electric storage models on its draw pattern, 81 have a higher UEF. For its type and draw pattern, the UEF runs from 0.88 to 0.95. Of the energy spent to reheat water, 98% goes into it (its recovery efficiency).

It is sold as E6-30R45DVB 1**, ENSB-30 1**, and PNSB-30 1**. All of its test figures are shared by 4 other basic models. They are listed under 4 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.