Does California discourage electric water heaters?
Contrary to popular belief, California does not discourage electric water heaters--use of electric water heaters, especially the heat pump water heaters, is encouraged. Depending on where you are in California, you can use natural gas (or propane) or electricity to generate hot water. California DOES want your water heater to be energy efficient so that our precious resources are not wasted. California Energy Code (Building Energy Efficiency Standards), Title 24, prescribes minimum energy efficiencies required for both gas and electric water heaters.
How would you know if you could use a gas water heater at a particular location in California?
Section 150.1(c)8 of the California Energy Standards (produced below) goes in detail about your choices.
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8. Domestic water-heating systems. Water-heating systems shall meet the requirements of A, B, C, or shall meet the performance compliance requirements of Section 150.1(b)1. For recirculation distribution systems, only demand recirculation systems with manual on/off control as specified in the Reference Appendix RA4.4.9 shall be used:
A. A single 240 volt heat pump water heater (HPWH). The storage tank shall be located in the garage or
conditioned space. In addition, meet the following:
i. A compact hot water distribution system as specified in the Reference Appendix RA4.4.6 in climate zone 1 and 16; and
ii. A drain water heat recovery system that is field verified as specified in the Reference Appendix RA3.6.9 in climate zone 16.
B. A single 240 volt HPWH that meets the requirements of NEEA Advanced Water Heater Specification Tier 3 or higher. In addition, for Climate Zone 16, a drain water heat recovery system that is field verified as specified in the Reference Appendix RA3.6.9 and the storage tank shall be located in the garage or conditioned space.
C. A solar water-heating system with electric backup meeting the installation criteria specified in Reference Residential Appendix RA4 and with a minimum annual solar savings fraction of 0.7.
Exception 1 to Section 150.1(c)8: For climate zones 3, 4, 13 and 14, a gas or propane instantaneous water heater with an input of 200,000 Btu per hour or less and no storage tank may be installed.
NOTE: The space conditioning system shall be a heat pump as specified in Section 150.1(c)6.
Exception 2 to Section 150.1(c)8: An instantaneous electric water heater with point of use distribution as specified in RA4.4.5 may be installed for new dwelling units with a conditioned floor area of 500 square feet or less.
Exception 3 to Section 150.1(c)8A and B: A 120V HPWH may be installed in place of a 240V HPWH for new dwelling unit with one bedroom or less.
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Consider the following examples not involving a re-circulation system or solar heating.
Example 1: You are building a new home of around 1200 sq. ft. in San Jose. What type of water heaters are allowed?
San Jose is in Climate Zone 4. You are allowed to use an instantaneous gas water heater (when using heat pump for space heating and cooling). You are also allowed to use an electric water heater that is a heat pump water heater. Because your floor area is over 500 sq. ft., you are not allowed to use an instantaneous electric water heater (electric resistance heating). And you are not allowed to have a storage type gas water heater.
If first cost matters most, you will go with an instantaneous gas water heater.
If operating cost is of concern, and you don't mind a slightly longer payback time, you will be better off installing a Heat Pump Water Heater.
Example 2: You are building an ADU of around 400 sq. ft. in Los Banos. What type of water heaters are allowed?
Los Banos is in Climate Zone 12. You are NOT allowed to use an instantaneous gas water heater. You are allowed to use an electric water heater that is a heat pump water heater. Because your floor area is less than 500 sq. ft., you are allowed to use an instantaneous electric water heater (electric resistance heating). And you are NOT allowed to have a storage type gas water heater.
If first cost matters most, you will go with an instantaneous electric water heater.
If operating cost is of concern, and you don't mind a slightly longer payback period, you will opt for a Heat Pump Water Heater.
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Images, courtesy of California Energy Commission.
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