120-Volt or 240-Volt Heat Pump Water Heater: What Title 24 Allows
It depends on the project. A new home on the prescriptive path names a 240-volt unit, with a 120-volt exception only for a dwelling of one bedroom or less. The rules for replacing an existing water heater and for additions do not state a voltage.
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Match your project to a row
- New home. The prescriptive options name a single 240-volt heat pump water heater. Exception 2 to Section 150.1(c)8A and B lets a 120-volt unit replace it for a new dwelling unit with one bedroom or less.
- Replacement in an existing home. Section 150.2(b)1H lists a single heat pump water heater with the tank indoors, on an incompressible rigid insulated surface of at least R-10 and with a CTA-2045-B or Section 110.12(a) interface, or one meeting NEEA Tier 3. No voltage is specified.
- Addition that adds a heater. Section 150.2(a)1D allows a single heat pump unit or a NEEA Tier 3 unit; for additions of 500 square feet or less, an electric water heater with point-of-use distribution also qualifies. Again, no voltage is stated.
Electric-ready does not decide it
The electric-ready rule applies when a gas water heater is installed. The compliance manual answers in Examples 10-2 and 10-3 that installing a heat pump water heater, split or integrated, at any voltage, carries no electric-ready requirement. The code's convertible form for gas homes is a 125-volt, 20-amp receptacle on a 120/240-volt three-conductor circuit rated 30 amps, which the manual says is meant to ease a later 240-volt change (Section 150.0(n)1A).
Conditions that apply at any voltage
Section 110.3(c)7 sets installation conditions for air-source heat pump water heaters. Backup heat is required when inlet air is unconditioned, unless the compressor cut-off temperature is below the winter median of extremes for the nearest listed location. Unducted consumer integrated units need room volume of at least 100 cubic feet per kBtu per hour of compressor capacity or permanent openings to a communicating space.
Practical checks before you buy
Confirm the panel can take the circuit the model needs, check the spot against the volume or opening condition, and match the model to the CF1R. The water heater requirements list the new-home options, heat pump water heater installation covers the CF2R side, and additions have their own page, as do ADUs. Start a report on the residential page.
Common Title 24 Questions
- When is Title 24 required for a home?
- Does a remodel need Title 24?
- Does a room addition need Title 24?
- What plans are needed for a residential Title 24 report?
- How much does a residential Title 24 report cost?
- How long does a residential Title 24 report take?
Frequently Asked Questions
Not under the prescriptive path. The 120-volt exception covers a new dwelling unit with one bedroom or less. A larger home would need another route, such as performance compliance.
Section 150.2(b)1H names no voltage for a replacement. The unit you buy sets the electrical need, and the electrical permit is decided locally.
Explore Water Heaters
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- Home Addition With a Heat Pump Water Heater: Title 24 Guide
- Can You Add a Hot Water Recirculation Pump Under Title 24?
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