Los Altos Municipal Code Ch. 12.16 Energy Code

There is hereby adopted by reference as if fully set forth herein, the 2025 California Energy Code, contained in the California Code of Regulations, Title 24, Part 6, published by the International Code Council, and each and all of its regulations and provisions. One (1) copy of said code is on file for use and examination by the public in the Development Services Department of the City of Los Altos.

(Ord. No. 2025-542, § 4, 10-28-2025)

Upon adoption of this Code in the event that there is any conflict between local amendments and the 2025 California Energy Code the most restrictive shall prevail.

A.

Amend Section 100.0 is to add a new section (i) as follows:

i.

Single Family Building Remodel Energy Reach Code - Purpose and Intent. In addition to all requirements of the California Energy Code applicable to Single Family building additions and alterations, the electric readiness measures specified in Sections 150.0(w) shall be required for certain single family additions and alterations.

B.

Amend Section 100.1(b) by adding the following definitions:

LEVEL 2 ELECTRIC VEHICLE (EV) CHARGING RECEPTACLE is a 208/240-volt 40-ampere minimum branch circuit and a receptacle.

LOW POWER LEVEL 2 ELECTRIC VEHICLE (EV) CHARGING RECEPTACLE is a 208/240-volt 20-ampere minimum branch circuit and a receptacle.

C.

Amend Section 150.0 to add a new section (w) as follows: (w) Electric Readiness for Remodels, Alterations and Additions

Electric range. Where branch circuits or receptacles are added or altered in a kitchen and the work requires an electrical permit, install electrical components in accordance with the California Electrical Code. The electrical components shall include either of the following:

A.

A 125 volt, 20 amp electrical receptacle that is connected to the electric panel with a 120/240 volt 3 conductor branch circuit rated at 50 amps minimum, within three feet from the appliance and accessible to the appliance with no obstructions. Both ends of the unused conductor shall be labeled with the word

"spare" and be electrically isolated. Space shall be reserved for a single pole circuit breaker in the electrical panel adjacent to the circuit breaker for the branch circuit and labeled with the words "Future Use."

B.

A pathway for a future 240 volt 50 amp minimum branch circuit that shall consist of either conductors or raceway from the main electrical service panel. The main electric panel shall have space reserved to allow for the installation of a double pole circuit breaker for a future electric range installation. The reserved space shall be permanently marked as "For Future 240V use." The raceway or conductors shall terminate at a junction box within three feet of the appliance. The blank cover shall be identified as "240V ready."

Electric dryer. Where a branch circuit is added or altered within three feet of a gas or propane clothes dryer and the work requires an electrical permit, install electrical components in accordance with the California Electrical Code. The electrical components shall include either of the following:

A.

A dedicated 125 volt, 20 amp electrical receptacle that is connected to the electric panel with a 120/240 volt 3 conductor branch circuit rated at 30 amps minimum, within three feet from the appliance and accessible to the appliance with no obstructions. Both ends of the unused conductor shall be labeled with the word "spare" and be electrically isolated. Space shall be reserved for a single pole circuit breaker in the electrical panel adjacent to the circuit breaker for the branch circuit and labeled with the words "Future Use"; or,

B.

A pathway for a future 240 volt 30 amp minimum branch circuit that shall consist of either conductors or raceway from the main electrical service panel. The main electric panel shall have space reserved to allow for the installation of a double pole circuit breaker for a future heat pump dryer installation. The reserved space shall be permanently marked as "For Future 240V use." The raceway or conductors shall terminate at a junction box within three feet of the appliance. The blank cover shall be identified as "240V ready."

Heat pump water heater.

A.

If wall framing is removed or replaced within three feet of a gas or propane water heating appliance, space suitable for the future installation of a heat pump water heater (HPWH) shall be provided. The space shall be at least 2.5 feet by 2.5 feet wide and seven feet tall and shall include a condensate drain that is no more than two inches higher than the base of an installed water heater and allows natural draining without pump assistance or installed piping or tubing within three feet of the water heater location to a condensate drain or exterior location. If pump assistance is needed, a receptacle on a 120 volt, minimum 15 amp branch circuit for a condensate pump must be available within three feet of the water heater location.

B.

Where branch circuits are altered or added within three feet of an existing gas or propane water heater or within 10 feet of the designated future location of a heat pump water heater as required under Section 150.0(w)3A, and the work requires an electrical permit, install electrical components in accordance with the California Electrical Code. The electrical components shall include either of the following:

i.

A dedicated 125 volt, 20 amp electrical receptacle that is connected to the electric panel with a 120/240 volt 3 conductor, 10 AWG copper branch circuit rated at 30 amps minimum, within three feet from the water heater and accessible to the water heater with no obstructions. Both ends of the unused conductor shall be labeled with the word "spare" and be electrically isolated. Space shall be reserved for a single pole circuit breaker space in the electrical panel adjacent to the circuit breaker for the branch circuit and labeled with the words "Future 240V Use"; or

ii.

A pathway for a future 240 volt 30 amp minimum branch circuit that shall consist of either conductors or raceway from the main electrical service panel. The main electric panel shall have space reserved to allow for the installation of a double pole circuit breaker for a future HPWH installation. The reserved space shall be permanently marked as "For Future 240V use." The pathway shall terminate at a junction box within three feet of the appliance. The blank cover shall be identified as "240V ready."

Outdoor gas appliances. Where a gas line is added or extended to any pool water heater, spa water heater, sauna, fireplace, outdoor cooking appliance, or outdoor heating system, install infrastructure and reserve physical space to accommodate future installation of an electric equivalent of that system that serves the same function, as certified by a registered design professional or licensed electrical contractor.

A.

Install conduit designed to serve a future electric appliance(s) with the same function, including the appropriate voltage, phase, minimum amperage, and an electrical receptacle or junction box within five feet of the appliance that is accessible with no obstructions, in accordance with manufacturer requirements and the California Electrical Code. In lieu of or in addition to conduit, electrically isolated branch circuit wiring may be installed; and

B.

Label both ends of the unused conduit or conductors "For Future Electrical Appliance"; and

C.

Reserve circuit breakers in the electrical panel(s) for each branch circuit, appropriately labeled; and

D.

Designate physical space for future electric appliances, including equipment footprint, on the construction drawings. The footprint necessary for future electric appliances may overlap with the location of currently

designed combustion equipment.

Exception to Section 150.0(w)4: Generator systems used for emergency power generation.

Electrical Power Upgrades. Increases in the electrical power infrastructure capacity serving a building shall only be permitted when all the following are documented and submitted to the building official:

A.

Calculations in accordance with California Electrical Code Article 220.83 determining future loads will exceed the capacity of the current electrical power infrastructure.

B.

Where data is available, calculations in accordance with California Electrical Code Article 220.87 determining that future loads exceed the capacity of the current electrical service infrastructure.

C.

Calculations for item (A) and item (B) above shall include at least one of the following:

i.

At least one power management or circuit controlling device, serving electric-only appliances such as:

a.

Water heater(s)

b.

Clothes dryer(s)

c.

Range(s)

d.

Level 2 EV Charging Receptacle or

e.

Low Power Level 2 EV Charging Receptacle

ii.

At least one of the following electric-only appliances operating on 120V:

a.

Water heater(s)

b.

Clothes dryers(s)

c.

Range(s)

iii.

Circuit control between whole home load and Level 2 EV Charging Receptacle or Low Power Level 2 EV Charging Receptacle

Exception 1 to Section 150.0(w)5: The upgrade is solely the result of a project proposing electrical improvements supporting loads related to devices and uses not regulated by 150.0(w).

Exception 1 to Section 150.0(w): The project is solely related to a repair as defined by Title 24 Part 2

Exception 2 to Section 150.0(w): If an electrical permit is not otherwise required for the project other than compliance with this section.

Exception 3 to Section 150.0(w): Where upgrades to the existing electrical panel or utility service are not proposed, electrical panel capacity shall not be required to exceed the existing utility electrical service to the building to meet compliance with this section. Capacity and overcurrent protection spaces shall be reserved to the extent allowable under the existing electrical panel capacity using the methodology in Section 150N.5. Tandem overcurrent protection devices shall be used to the extent permissible under the California Electrical Code.

Exception 4 to Section 150.0(w): A Covered Single-Family Project that consists solely of medically necessary improvements or solely of seismic safety improvements

Exception 5 to Section 150.0(w): Mobile Homes, Manufactured Housing, or Factory-built Housing as defined in Division 13 of the California Health and Safety 12 Code (commencing with Section 17000 of the Health and Safety Code).

Exception 6 to Section 150.0(w): Emergency Housing pursuant to Appendix P of the California Building Code.

Exception 7 to Section 150.0(w): Creation of a new accessory dwelling unit or junior accessory dwelling unit that is within the existing space of a single-family dwelling or accessory structure and includes an expansion of not more than 150 square feet beyond the same physical dimensions as the existing accessory structure. An expansion beyond the physical dimensions of the existing accessory structure shall be limited to accommodating ingress and egress. Or, if the project would not otherwise be a Covered Single-Family Project were it not for the inclusion of an accessory dwelling unit or junior accessory dwelling unit that meets the criteria above.

D.

Amend Section 150.2(b)1C to read:

C. Entirely new or complete replacement space-conditioning systems installed as part of an alteration, shall include all the system heating or cooling equipment, including but not limited to: condensing unit cooling or heating coil, and air handler for split systems; or complete replacement of a packaged unit; plus entirely new or replacement duct system (Section 150.2(b)1Diia).

Entirely new or complete replacement space-conditioning systems shall meet the requirements of Sections 150.0(h), 150.0(i), 150.0(j)1, 150.0(j)2, 150.0(m)1 through 150.0(m)10; 150.0(m)12; 150.0(m)13, 150.1(c)7,150.2(b)1G, and TABLE 150.2-A. Additionally, where an entirely new or complete replacement space conditioning system includes a new or replacement air-cooled air conditioner in Climate Zones 1 through 14 and 16, it shall meet the applicable requirements of Section 150.2(b)1Fiv. Where an entirely new or complete replacement space conditioning system includes a new or replacement heat pump, it shall meet the applicable requirements of Section 150.2(b)1Fv.

E.

Amend Section 150.2(b)1F to read:

F.

Altered space-conditioning system - mechanical cooling. Alterations which install new or replacement air- cooled air conditioners shall meet the applicable requirements of subsections i and iv. Alterations which install new or replacement heat pumps shall meet the applicable requirements of subsections i, ii, iii, and v. All other alterations to refrigerant containing components such as the compressor, condensing coil, evaporator coil, refrigerant metering device, or refrigerant piping, shall meet the applicable requirements of subsections i, ii, and iii.

i.

All thermostats associated with the system shall be replaced with setback thermostats meeting the requirements of Section 110.2(c).

ii.

Air-cooled air conditioners in Climate Zones 2 and 8 through 15 and air-source heat pumps in all climate zones, including but not limited to ducted split systems, ducted package systems, small duct high velocity air systems, and minisplit systems, shall comply with Subsections a and b, unless the system is of a type that cannot be verified using the specified procedures. Systems that cannot comply with the requirements of 150.2(b)1Fii shall comply with Section 150.2(b)1Fiii.

Exception to Section 150.2(b)1Fii: Entirely new or complete replacement packaged systems for which the manufacturer has verified correct system refrigerant charge prior to shipment from the factory are not required to have refrigerant charge confirmed through field verification and diagnostic testing. The installer of these packaged systems shall certify on the Certificate of Installation that the packaged system was pre- charged at the factory and has not been altered in a way that would affect the charge. Ducted systems

shall comply with minimum system airflow rate requirement in Section 150.2(b)1Fiia, provided that the system is of a type that can be verified using the procedure specified in RA3.3 or an approved alternative in RA1.

a.

Minimum system airflow rate shall comply with the applicable Subsection I or II below as confirmed through field verification and diagnostic testing in accordance with the procedures specified in Reference Residential Appendix Section RA3.3 or an approved alternative procedure as specified in Section RA1.

I.

Small duct high velocity systems shall demonstrate a minimum system airflow rate greater than or equal to 250 cfm per ton of nominal cooling capacity; or

II.

All other air-cooled air conditioner or air-source heat pump systems shall demonstrate a minimum system airflow rate greater than or equal to 300 cfm per ton of nominal cooling capacity; and

Exception 1 to Section 150.2(b)1Fiia: Systems unable to comply with the minimum airflow rate requirement shall demonstrate compliance using the procedures in Section RA3.3.3.1.5; and the system's thermostat shall conform to the specifications in Section 110.12.

Exception 2 to Section 150.2(b)1Fiia: Entirely new or complete replacement space conditioning systems, as specified by Section 150.2(b)1C, without zoning dampers may comply with the minimum airflow rate by meeting the applicable requirements in Tables-150.0-B or 150.0-C as confirmed by field verification and diagnostic testing in accordance with the procedures in Reference Residential Appendix Section RA3.1.4.4 and RA3.1.4.5. The design clean-filter pressure drop requirements of Section 150.0(m)12C for the system air filter device(s) shall conform to the requirements given in Tables 150.0-B and 150.0-C.

b.

The installer shall charge the system according to manufacturer's specifications. Refrigerant charge shall be verified according to one of the following options, as applicable.

I.

The installer and rater shall perform the standard charge verification procedure as specified in Reference Residential Appendix Section RA3.2.2, or an approved alternative procedure as specified in Section RA1; or

II.

The installer shall perform the weigh-in charging procedure as specified by Reference Residential Appendix Section RA3.2.3.1 provided the system is of a type that can be verified using the RA3.2.2 standard charge verification procedure and RA3.3 airflow rate verification procedure or approved alternatives in RA1. The ECC-Rater shall verify the charge using RA3.2.2 and RA3.3 or approved alternatives in RA1.

Exception 1 to Section 150.2(b)1Fiib: When the outdoor temperature is less than 55° F and the installer utilizes the weigh-in charging procedure in Reference Residential Appendix Section RA3.2.3.1to demonstrate compliance, the installer may elect to utilize the verification procedure in Reference Residential Appendix Section RA3.2.3.2. If the verification procedure in Section RA3.2.3.2 is used for compliance, the system's thermostat shall conform to the specifications in Section 110.12. Ducted systems shall comply with the minimum system airflow rate requirements in Section 150.2(b)1Fiia.

iii.

Air-cooled air conditioners in Climate Zones 2 and 8 through 15 and air-source heat pumps in all climate zones, including but not limited to ducted split systems, ducted package systems, small duct high velocity, and minisplit systems, which are of a type that cannot comply with the requirements of 150.2(b)1Fiib shall comply with subsections a and b, as applicable.

a.

The installer shall confirm the refrigerant charge using the weigh-in charging procedure specified in Reference Residential Appendix Section RA3.2.3.1, as verified by an ECC-Rater according to the procedures specified in Reference Residential Appendix RA3.2.3.2; and

b.

Systems that utilize forced air ducts shall comply with the minimum system airflow rate requirement in Section 150.2(b)1Fiia provided the system is of a type that can be verified using the procedures in Section RA3.3 or an approved alternative procedure in Section RA1.

Exception to Section 150.2(b)1Fiii: Entirely new or complete replacement packaged systems for which the manufacturer has verified correct system refrigerant charge prior to shipment from the factory are not required to have refrigerant charge confirmed through field verification and diagnostic testing. The installer of these packaged systems shall certify on the Certificate of Installation that the packaged system was pre- charged at the factory and has not been altered in a way that would affect the charge. Ducted systems shall comply with minimum system airflow rate requirement in Section 150.2(b)1Fiiib, provided that the system is of a type that can be verified using the procedure specified in Section RA3.3 or an approved alternative in Section RA1.

iv.

New or replacement air-cooled air conditioners in Climate Zones 1 through 14 and 16 shall meet the requirements of Section 150.2(b)1Fiva or 150.2(b)1Fivb.

a.

Systems with existing duct distribution systems shall meet the following requirements:

I.

In all climate zones, meet the airflow and fan efficacy requirements of Section 150.0(m)13B, 150.0(m)13C, or 150.0(m)13D.

Exception 1 to Section 150.2(b)1FivaI: Single zone central forced air systems and zonally controlled central forced air systems may demonstrate compliance with an airflow greater than or equal to 300 CFM per ton of nominal cooling capacity.

II.

In all climate zones, meet the refrigerant charge verification requirements of Section 150.2(b)1Fii; and

III.

In all climate zones, vented attics shall have insulation installed to achieve a U-factor of 0.020 or insulation installed at the ceiling level shall result in an insulated thermal resistance of R-49 or greater for the insulation alone; luminaires not rated for insulation contact must be replaced or retrofitted with a fireproof cover that allows for insulation to be installed directly over the cover; and

Exception 1 to Section 150.2(b)1FivaIII: Dwelling units with at least R-38 existing insulation installed at the ceiling level.

Exception 2 to Section 150.2(b)1FivaIII: Dwelling units where the alteration would directly cause the disturbance of asbestos unless the alteration is made in conjunction with asbestos abatement.

Exception 3 to Section 150.2(b)1FivaIII: Dwelling units with knob and tube wiring located in the vented attic.

Exception 4 to Section 150.2(b)1FivaIII: Where the accessible space in the attic is not large enough to accommodate the required R-value, the entire accessible space shall be filled with insulation provided such installation does not violate Section 806.3 of Title 24, Part 2.5.

Exception 5 to Section 150.2(b)1FivaIII: Where the attic space above the altered dwelling unit is shared with other dwelling units and the requirements of Section 150.2(b)1FivalII are not triggered for the other dwelling units.

IV.

In all climate zones, air seal all accessible areas of the ceiling plane between the attic and the conditioned space in accordance with Section 110.7.

Exception 1 to Section 150.2(b)1FivaIV: Dwelling units with at least R-38 existing insulation installed at the ceiling level.

Exception 2 to Section 150.2(b)1FivaIV: Dwelling units where the alteration would directly cause the disturbance of asbestos unless the alteration is made in conjunction with asbestos abatement.

Exception 3 to Section 150.2(b)1FivaIV: Dwelling units with atmospherically vented space heating or water heating combustion appliances located inside the pressure boundary of the dwelling unit.

b.

Systems with entirely new or complete replacement duct systems shall meet the following:

I.

R-8 duct insulation shall be installed for all new ducts located in unconditioned space; and

II.

In all climate zones, meet the airflow requirements of Section 150.0(m)13B, 150.0(m)13C, or 150.0(m)13D and demonstrate an air-handling unit fan efficacy of less than or equal to 0.35 W/CFM.

III.

In all climate zones, meet the refrigerant charge verification requirements of Section 150.2(b)1Fii;

Exception 1 to Section 150.2(b)1Fiv: Where the capacity of the existing main electrical service panel is insufficient to supply the electrical capacity of a heat pump and where the existing main electrical service panel is sufficient to supply a new or replacement air conditioner, as calculated according to the requirements of California Electrical Code Article 220.83 or Article 220.87, systems shall comply with the applicable requirements of Sections 150.2(b)1Fi, 150.2(b)1Fii, and 150.2(b)1Fiii. Documentation of electrical load calculations in accordance with Article 220 must be submitted to the enforcement agency prior to permitting both the heat pump and proposed air conditioner.

Exception 2 to Section 150.2(b)1Fiv: Where the required capacity of a heat pump to meet the system selection requirements of Section 150.0(h)5 is greater than or equal to 12,000 Btu/h more than the greater of the required capacity of an air conditioner to meet the design cooling load OR the capacity of the existing air conditioner, systems shall comply with the applicable requirements of Sections 150.2(b)1Fi, 150.2(b)1Fii, and 150.2(b)1Fiii. Documentation of heating and cooling load calculations in accordance with 150.0(h) must be submitted to the enforcement agency prior to permitting for both the heat pump and proposed air conditioner.

v.

In all climate zones, heat pumps with supplementary heat, including, but not limited to, electric resistance heaters or gas furnace supplementary heating, shall comply with Section 150.0(h)7 and shall lock out supplementary heating above an outdoor air temperature of no greater than 35°F.

F.

Amend Section 150.2(b)2 to read: Performance approach. The energy budget for alterations is expressed in terms of Long-term System Cost (LSC), and the altered component(s) and any newly installed equipment serving the alteration shall meet the applicable requirements of Subsections A, B, and C below.

A.

The altered components shall meet the applicable requirements of Sections 110.0 through 110.9, Sections 150.0(a) through (l), Sections 150.0(m)1 through 150.0 (m)10, and Sections 150.0(p) through (q). Entirely new or complete replacement mechanical ventilation systems as these terms are used in Section 150.2(b)1L, shall comply with the requirements in Section 150.2(b)1L. Altered mechanical ventilation systems shall comply with the requirements of Section 150.2(b)1M. Entirely new or complete replacement space-conditioning systems, and entirely new or complete replacement duct systems, as these terms are used in Sections 150.2(b)1C and 150.2(b)1Diia, shall comply with the requirements of Sections 150.0(m)12

and 150.0(m)13. New or replacement air-cooled air conditioners in Climate Zones 1 through 14 and 16 shall meet the applicable requirements of Section 150.2(b)1Fiv.

B.

The standard design for an altered component shall be the higher efficiency of existing conditions or the requirements stated in Table 150.2-G. For components not being altered, the standard design shall be based on the existing conditions. When the third party verification option is specified as a requirement, all components proposed for alteration for which the additional credit is taken, must be verified by a certified ECC-rater.

Table 150.2-G is hereby amended to read:

Table 150.2-G Standard Design for an Altered Component

Altered Component Standard Design Without Third Party Standard Design With Third Party Verification of Existing Conditions Shall be Verification of Existing Conditions Based On Shall be Based On

Ceiling Insulation, The requirements of Sections 150.0(a), (c), The existing insulation R-value Wall Insulation, and and (d). The requirements of Section Raised-floor 150.2(b)1J for altered ceilings and for entirely Insulation new or complete replacement duct systems where the air handler and ducts are located within a vented attic. The requirements of Section 150.2(b)1Fiv for alterations which include new or replacement air-cooled air conditioners.

Fenestration The requirements of Section 150.1(c)3A. The existing fenestration U-factor and SHGC values as verified.

Window Film The requirements of Section 150.1(c)3A. The existing fenestration in the alteration shall be based on TABLE 110.6-A and TABLE 110.6- B.

Doors The U-factor of 0.20. The door area shall be If the proposed U-factor is ≤ 0.20, the door area of the existing building. the standard design shall be based on the existing U-factor value as verified. Otherwise, the standard design shall be based on the U-factor of 0.20. The door area shall be the door area of the existing.

Space-Heating and Table 150.1-A for equipment efficiency The existing efficiency levels. Space-Cooling requirements; Section 150.2(b)1C for entirely Equipment new or complete replacement systems;

Section 150.2(b)1F for refrigerant charge verification, airflow, and fan efficacy requirements. Section 150.2(b)1Fiv for new or replacement air-cooled air conditioners

Air Distribution The requirements of Sections 150.2(b)1D and The requirements of Sections System - Duct 150.2(b)1E 150.2(b)1D and 150.2(b)1E Sealing

Air Distribution The requirements of Sections 150.2(b)1D, The existing efficiency levels. System - Duct and for new or replacement air-cooled air Insulation conditioners, Section 150.2(b)1Fiv.

Water Heating The requirements of Section 150.2(b)1Hii The existing efficiency level. Systems

Roofing Products The requirements of Section 150.2(b)1I. The requirements of Section 150.2(b)1I

All Other Measures The proposed efficiency levels. The existing efficiency levels.

C.

The proposed design shall be based on the actual values of the altered components.

(Ord. No. 2025-542, § 4, 10-28-2025)