EXCEPTIONS: | 1. Where not less than 25 percent of the annual service water-heating requirement is provided from any of the following sources: |
1.1. Renewable energy generated on-site that is not being used to satisfy another requirement of this code; or | |
1.2. Site-recovered energy that is not being used to satisfy other requirements of this code. | |
2. Redundant equipment intended to only operate during equipment failure or periods of extended maintenance. | |
3. Electric resistance heated systems installed as part of an alteration where the water heating equipment is installed at the grade level in a building with a height of four stories or greater. | |
4. Hot water heat exchangers used to provide service water heating from a district utility (steam, heating hot water). | |
5. Water heaters provided as an integral part of equipment intended to only heat or boost the heat of water used by that equipment. | |
6. For electric heat systems, supplemental water heaters not meeting this criteria that function as auxiliary heating only when the outdoor temperature is below 32°F (0°C) or when a defrost cycle is required are not required to have a rated COP of 2.0. Such systems shall be sized and configured to lock out electric resistance or fossil fuel heating from operation when the outdoor temperature is above 32°F (0°C) unless the system is in defrost operation. |
EXCEPTION: | Compliance with this section is not required if the combined input-capacity-weighted average equipment rating for each service water heating fuel source type is not less than the following: |
1. Electric Resistance: An electric resistance water heater with a rating of 105 percent of the rated efficiency of Table C404.2. | |
2. Electric Heat Pump (10 C.F.R. Part 430): A heat pump water heater rated in accordance with 10 C.F.R. Part 430 with a rating of 105 percent of the rated efficiency of Table C404.2. | |
3. Electric Heat Pump (not listed in accordance with 10 C.F.R. Part 430): A heat pump water heater not rated in accordance with 10 C.F.R. Part 430 shall have a COP of not less than 2.0. For air-source heat pump equipment the COP rating will be reported at the design leaving heat pump water temperature with an entering air temperature of 60°F (15.6°C) or less. Supplemental water heaters not meeting the above criteria that function as auxiliary heating only when the outdoor temperature is below 32°F (0°C) or when a defrost cycle is required are not required to have a rated COP of 2.0. Such systems shall be sized and configured to lock out electric resistance or fossil fuel heating from operation when the outdoor temperature is above 32°F (0°C) unless the system is in defrost operation. | |
4. Fossil Fuels: A rated Et of not less than 90 percent as determined by the applicable test procedures in Table C404.2. | |
5. Hot water heat exchangers used to provide service water heating from a district utility (steam, heating hot water). |
EXCEPTIONS: | 1. Where not less than 25 percent of the annual service water-heating requirement is provided from any of the following sources: |
1.1. Renewable energy generated on-site that is not being used to satisfy another requirement of this code; or | |
1.2. Site-recovered energy that is not being used to satisfy other requirements of this code. | |
2. Redundant equipment intended to only operate during equipment failure or periods of extended maintenance. | |
3. Electric resistance heated systems installed as part of an alteration where the water heating equipment is installed at the grade level in a building with a height of four stories or greater. | |
4. Hot water heat exchangers used to provide service water heating from a district utility (steam, heating hot water). | |
5. Water heaters provided as an integral part of equipment intended to only heat or boost the heat of water used by that equipment. | |
6. For electric heat systems, supplemental water heaters not meeting this criteria that function as auxiliary heating only when the outdoor temperature is below 32°F (0°C) or when a defrost cycle is required are not required to have a rated COP of 2.0. Such systems shall be sized and configured to lock out electric resistance or fossil fuel heating from operation when the outdoor temperature is above 32°F (0°C) unless the system is in defrost operation. |
EXCEPTION: | Compliance with this section is not required if the combined input-capacity-weighted average equipment rating for each service water heating fuel source type is not less than the following: |
1. Electric Resistance: An electric resistance water heater with a rating of 105 percent of the rated efficiency of Table C404.2. | |
2. Electric Heat Pump (10 C.F.R. Part 430): A heat pump water heater rated in accordance with 10 C.F.R. Part 430 with a rating of 105 percent of the rated efficiency of Table C404.2. | |
3. Electric Heat Pump (not listed in accordance with 10 C.F.R. Part 430): A heat pump water heater not rated in accordance with 10 C.F.R. Part 430 shall have a COP of not less than 2.0. For air-source heat pump equipment the COP rating will be reported at the design leaving heat pump water temperature with an entering air temperature of 60°F (15.6°C) or less. Supplemental water heaters not meeting the above criteria that function as auxiliary heating only when the outdoor temperature is below 32°F (0°C) or when a defrost cycle is required are not required to have a rated COP of 2.0. Such systems shall be sized and configured to lock out electric resistance or fossil fuel heating from operation when the outdoor temperature is above 32°F (0°C) unless the system is in defrost operation. | |
4. Fossil Fuels: A rated Et of not less than 90 percent as determined by the applicable test procedures in Table C404.2. | |
5. Hot water heat exchangers used to provide service water heating from a district utility (steam, heating hot water). |