Water-heating equipment and hot water storage tanks shall meet the requirements of Table C404.2. The efficiency shall be verified through data furnished by the manufacturer or through certification under an *approved *certification program.

TABLE C404.2

MINIMUM PERFORMANCE OF WATER-HEATING EQUIPMENT

EQUIPMENT TYPE | SIZE CATEGORY (input) | SUBCATEGORY OR RATING CONDITION | PERFORMANCE REQUIRED ^{a, b} | TEST PROCEDURE |

Water heaters, electric | ≤ 12 kW | Resistance | 0.97 - 0.00 132V, EF | DOE 10 CFR Part 430 |

> 12 kW | Resistance | 1.73V+ 155 SL, Btu/h | ANSI Z21.10.3 | |

≤ 24 amps and ≤ 250 volts | Heat pump | 0.93 - 0.00 132V, EF | DOE 10 CFR Part 430 | |

Storage water heaters, gas | ≤ 75,000 Btu/h | ≥ 20 gal | 0.67 - 0.0019V, EF | DOE 10 CFR Part 430 |

> 75,000 Btu/h and ≤ 155,000 Btu/h | < 4,000 Btu/h/gal | ANSI Z21.10.3 | ||

> 155,000 Btu/h | < 4,000 Btu/h/gal | | ||

Instantaneous water heaters, gas | > 50,000 Btu/h and < 200,000 Btu/h ^{c} | ≥ 4,000 (Btu/h)/gal and < 2 gal | 0.62 - 0.00 19V, EF | DOE 10 CFR Part 430 |

≥ 200,000 Btu/h | ≥ 4,000 Btu/h/gal and < 10 gal | 80% E_{t} | ANSI Z21.10.3 | |

≥ 200,000 Btu/h | ≥ 4,000 Btu/h/gal and ≥ 10 gal | |||

Storage water heaters, oil | ≤ 105,000 Btu/h | ≥ 20 gal | 0.59 - 0.0019V, EF | DOE 10 CFR Part 430 |

≥ 105,000 Btu/h | < 4,000 Btu/h/gal | | ANSI Z21.10.3 | |

Instantaneous water heaters, oil | ≤ 210,000 Btu/h | ≥ 4,000 Btu/h/gal and < 2 gal | 0.59 - 0.0019V, EF | DOE 10 CFR Part 430 |

> 210,000 Btu/h | ≥ 4,000 Btu/h/gal and < 10 gal | 80% E_{t} | ANSI Z21.10.3 | |

> 210,000 Btu/h | ≥ 4,000 Btu/h/gal and ≥ 10 gal | | ||

Hot water supply boilers, gas and oil | ≥ 300,000 Btu/h and < 12,500,000 Btu/h | ≥ 4,000 Btu/h/gal and < 10 gal | 80% E_{t} | ANSI Z21.10.3 |

Hot water supply boilers, gas | ≥ 300,000 Btu/h and < 12,500,000 Btu/h | ≥ 4,000 Btu/h/gal and ≥ 10 gal | | |

Hot water supply boilers, oil | > 300,000 Btu/h and < 12,500,000 Btu/h | > 4,000 Btu/h/gal and > 10 gal | | |

Pool heaters, gas and oil | All | — | 82% E_{t} | ASHRAE 146 |

Heat pump pool heaters | All | — | 4.0 COP At low air temperature | AHRI 1160^{d, e} |

Unfired storage tanks | All | — | Minimum insulation requirement R-12.5 (h • ft ^{2} • °F)/Btu | (none) |

For SI: °C = [(°F) - 32]/1.8, 1 British thermal unit per hour = 0.2931 W, 1 gallon = 3.785 L, 1 British thermal unit per hour per gallon = 0.078 W/L.

- Energy factor (EF) and thermal efficiency (
*E*) are minimum requirements. In the EF equation,_{t}*V*is the rated volume in gallons. - Standby loss (SL) is the maximum Btu/h based on a nominal 70°F temperature difference between stored water and ambient requirements. In the SL equation,
*Q*is the nameplate input rate in Btu/h. In the SL equation for electric water heaters,*V*is the rated volume in gallons. In the SL equation for oil and gas water heaters and boilers,*V*is the rated volume in gallons. - Instantaneous water heaters with input rates below 200,000 Btu/h must comply with these requirements if the water heater is designed to heat water to temperatures 180°F or higher.
- Test report from independent laboratory is required to verify procedure compliance.
- Geothermal swimming pool heat pumps are not required to meet this standard.