These tables list the minimum uniform energy factors (UEF) required by federal regulations for some of the most common types and sizes of water heaters.
Note: These values apply to water heaters manufactured before May 6, 2029.
General Information
Consumer Gas-Fired Instantaneous (> 50,000 Btu/h, ≤ 200,000 Btu/h) - Minimum UEF*
| Volume (gallons) | Max Rating 0 ≤ GPM < 1.7 | Max Rating 1.7 ≤ GPM < 2.8 | Max Rating 2.8 ≤ GPM < 4.0 | Max Rating GPM ≥ 4.0 |
| < 2 | 0.80 | 0.81 | 0.81 | 0.81 |
*Values from Title 20 §1605.1 Table F-2
Consumer Gas-Fired Storage (≤ 75,000 Btu/h) - Minimum UEF*
| Volume (gallons) | 0 ≤ FHR < 18 | 18 ≤ FHR < 51 | 51 ≤ FHR < 75 | FHR ≥ 75 |
| 30 | 0.29 | 0.54 | 0.60 | 0.65 |
| 40 | 0.27 | 0.52 | 0.58 | 0.64 |
| 50 | 0.25 | 0.50 | 0.56 | 0.63 |
| 55 | 0.24 | 0.49 | 0.55 | 0.62 |
| 60 | 0.61 | 0.74 | 0.77 | 0.79 |
| 75 | 0.60 | 0.73 | 0.76 | 0.78 |
| 80 | 0.60 | 0.73 | 0.76 | 0.78 |
*Values from Title 20, §1605.1 Table F-2
Residential-Duty Commercial Gas-Fired Storage (> 75,000 Btu/h, ≤ 105,000 Btu/h) - Minimum UEF†
| Volume (gallons) | 0 ≤ FHR < 18 | 18 ≤ FHR < 51 | 51 ≤ FHR < 75 | FHR ≥ 75 |
| 50 | 0.22 | 0.48 | 0.55 | 0.61 |
| 60 | 0.21 | 0.46 | 0.53 | 0.61 |
| 75 | 0.20 | 0.45 | 0.52 | 0.59 |
| 80 | 0.20 | 0.44 | 0.51 | 0.59 |
†Values from Title 20, §1605.1 Table F-5
Consumer Electric Instantaneous (≤ 12 kW) - Minimum UEF*
| Volume (gallons) | Max Rating 0 ≤ GPM < 1.7 | Max Rating 1.7 ≤ GPM < 2.8 | Max Rating 2.8 ≤ GPM < 4.0 | Max Rating GPM ≥ 4.0 |
| < 2 | 0.91 | 0.91 | 0.91 | 0.92 |
*Values from Title 20, §1605.1 Table F-2
Residential-Duty Commercial Electric Instantaneous (> 12 kW, ≤ 58.6 kW) - Minimum UEF†
| Volume (gallons) | Max Rating 0 ≤ GPM < 1.7 | Max Rating 1.7 ≤ GPM < 2.8 | Max Rating 2.8 ≤ GPM < 4.0 | Max Rating GPM ≥ 4.0 |
| < 2 | 0.80 | 0.80 | 0.80 | 0.80 |
| Btu/h British thermal units per hour | kW Kilowatt | GPM Gallons per minute | FHR First hour rating | UEF Uniform Energy Factor |
†Values from Title 20, §1605.1 Table F-5
Consumer Electric Storage - Minimum UEF*
| Volume (gallons) | 0 ≤ FHR < 18 | 18 ≤ FHR < 51 | 51 ≤ FHR < 75 | FHR ≥ 75 |
| 30 | 0.86 | 0.92 | 0.92 | 0.93 |
| 40 | 0.85 | 0.91 | 0.92 | 0.93 |
| 50 | 0.84 | 0.91 | 0.92 | 0.93 |
| 55 | 0.84 | 0.91 | 0.92 | 0.93 |
| 60 | 1.86 | 1.98 | 2.05 | 2.18 |
| 75 | 1.84 | 1.96 | 2.03 | 2.16 |
| 80 | 1.84 | 1.96 | 2.03 | 2.15 |
*Values from Title 20, §1605.1 Table F-2
Tabletop - Minimum UEF*
| Volume (gallons) | Max Rating 0 ≤ GPM < 1.7 | Max Rating 1.7 ≤ GPM < 2.8 | Max Rating 2.8 ≤ GPM < 4.0 | Max Rating GPM ≥ 4.0 |
| 30 | 0.46 | 0.83 | 0.89 | 0.94 |
| 40 | 0.40 | 0.79 | 0.87 | 0.92 |
*Values from Title 20, §1605.1 Table F-2
Frequently Asked Questions
See the Blueprint for more information, including articles and frequently asked questions about the 2025 Energy Code.