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Title 16 — BUILDING REGULATIONS›Chapter 16.17 — CALIFORNIA ENERGY CODE, CALIFORNIA CODE OF

Section 150.2 – Energy Efficiency Standards for Additions and Alterations to Existing…

Palo Alto Municipal Code · 2026-09 edition · updated 2026-09-29 · Palo Alto

2025 California Energy Code is adopted without amendment, except as follows (additions underlined, deletions struck through):

Section 150.2(b)1C is hereby amended 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)1D.ii.a). 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)1F.ii, 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)1.F.v.

Section 150.2(b)1.F. is hereby amended 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. When a space- conditioning system is an air conditioner or heat pump that is altered by the installation or replacement of refrigerant-containing system components such as the compressor, condensing coil, evaporator coil, refrigerant metering device or refrigerant piping, the altered system shall comply with the following requirements:

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 airsource heat pumps in all climate zones, including but not limited to

ducted split systems, ducted package systems, small duct high velocity air systems, and mini-split 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)1.F.ii shall comply with Section 150.2(b)1.F.iii.

Exception to Section 150.2(b)1.F.ii: 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)1.F.ii.a, 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.

Exception 1 to Section 150.2(b)1.F.ii.a: 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)1.F.ii.a: 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 Tables150.0-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)1.F.ii.b: When the outdoor temperature is less than 55°F and the installer utilizes the weigh-in charging

procedure in Reference Residential Appendix Section RA3.2.3.1 to 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)1.F.ii.a.

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 mini-split systems, which are of a type that cannot comply with the requirements of 150.2(b)1.F.ii.b 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)1.F.ii.a 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)1.F.iii: 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)1.F.iii.b, 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)1F.iv.a.I: 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)1.F.ii; 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)1F.iv.a.III: Dwelling units with at least R-38 existing insulation installed at the ceiling level.

Exception 2 to Section 150.2(b)1.F.iv.a.III: 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)1.F.iv.a.III: Dwelling units with knob and tube wiring located in the vented attic.

Exception 4 to Section 150.2(b)1F.iv.a.III: 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)1F.iv.a.III: Where the attic space above the altered dwelling unit is shared with other dwelling units and

the requirements of Section 150.2(b)1.F.iv.a.III 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)1.F.iv.a.IV: Dwelling units with at least R-38 existing insulation installed at the ceiling level.

Exception 2 to Section 150.2(b)1.F.iv.a.IV: 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)1.F.iv.a.IV: 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.

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)1.F.ii.

Exception 1 to Section 150.2(b)1.F.iv: 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)1.F.i, 150.2(b)1.F.ii, and 150.2(b)1.F.iii. Documentation of electrical load calculations in accordance with Article 220 must be submitted to the enforcement agency prior to permitting for both the heat pump and proposed air conditioner.

Exception 2 to Section 150.2(b)1.F.iv: 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)1.F.i, 150.2(b)1.F.ii, and 150.2(b)1.F.iii. 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.

Section 150.2(b)2 is hereby amended to read:

  1. 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)1D.ii.a, 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

Standard Design Without Third Party Standard Design With Third Party Verification Altered Component Verification of Existing Conditions Shall be of Existing Conditions Shall be Based On Based On The requirements of Sections 150.0(a), (c), and (d). The requirements of Section 150.2(b)1J for altered ceilings and for entirely new or Ceiling Insulation, Wall Insulation, and Raised- complete replacement duct systems where the The existing insulation R-value floor Insulation air handler and ducts are located within a vented attic. The requirements of Section 150.2(b)1.F.iv for alterations which include new or replacement air-cooled air conditioners. The existing fenestration U-factor and SHGC Fenestration The requirements of Section 150.1(c)3A. values as verified The existing fenestration in the alteration shall Window Film The requirements of Section 150.1(c)3A. be based on Table 110.6-A and Table 110.6-B. If the proposed U-factor is <0.20, the standard design shall be based on the The U-factor of 0.20. The door area shall be existing U-factor value as verified. Otherwise, Doors the door area of the existing building. the standard design shall be based on the U- factor of 0.20. The door area shall be the door area of the existing building. Table 150.1-A for equipment efficiency requirements; Section 150.2(b)1C for entirely new or complete replacement systems; Space-Heating and Space-Cooling Equipment Section 150.2(b)1F for refrigerant change The existing efficiency levels. verification, airflow, and fan efficacy requirements. Section 150.2(b)1Fiv for new or replacement air-cooled air conditioners The requirements of Sections 150.2(b)1D and The requirements of Sections 150.2(b)1D and Air Distribution System - Duct Sealing 150.2(b)1E. 150.2(b)1E. The proposed efficiency levels. The requirements of Sections 150.2(b)1D, and Air Distribution System - Duct Insulation The existing efficiency levels. for new or replacement air-cooled air conditioners, Section 150.2(b)1F.iv. Water Heating Systems The requirements of Section 150.2(b)1.H.ii. The existing efficiency levels. Roofing Products The requirements of Section 150.2(b)1.I. The requirements of Section 150.2(b)1.I. 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. 5665 § 2 (part), 2025)

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▸Contents — Palo Alto Municipal Code
Palo Alto Municipal Code
  1. Article VIII — A. Board of Education
  2. Title 1 — GENERAL PROVISIONS
  3. Title 2 — ADMINISTRATIVE CODE
  4. Title 4 — BUSINESS LICENSES AND REGULATIONS
  5. Title 5 — HEALTH AND SANITATION
  6. Title 6 — ANIMALS
  7. Title 8 — TREES AND VEGETATION
  8. Title 9 — PUBLIC PEACE, MORALS AND SAFETY
  9. Title 10 — VEHICLES AND TRAFFIC
  10. Title 11 — ENVIRONMENTAL IMPACT PROCEDURE
  11. Title 12 — PUBLIC WORKS AND UTILITIES
  12. Title 13 — IMPROVEMENT PROCEDURE
  13. Title 15 — FIRE PREVENTION
  14. ▸Title 16 — BUILDING REGULATIONS
    Overview
    1. 16.04 California Building Code, California Code of Regulations…
    2. 16.05 California Mechanical Code, California Code of Regulatio…
    3. 16.08 California Plumbing Code, California Code of Regulations…
    4. 16.09 Sewer Use Ordinance
    5. 16.10 Private Sewage Disposal Systems
    6. 16.11 Stormwater Pollution Prevention
    7. 16.12 Recycled Water
    8. 16.13 Requirements for Food Facilities Related to Water Pollut…
    9. 16.14 California Green Building Standards Code, California Cod…
    10. 16.15 Electric Vehicle Charging Stations
    11. 16.17 California Energy Code, California Code of Regulations, …
    12. 16.19 California Historical Building Code, California Code of …
    13. 16.20 Signs
    14. 16.24 Fences
    15. 16.28 Excavations, Grading and Fills
    16. 16.32 Moving and Relocating Buildings
    17. 16.36 House Numbering
    18. 16.38 Certificate of Use and Occupancy for Community Housing
    19. 16.40 Unsafe Buildings
    20. 16.42 Seismic Hazards Identification Program
    21. 16.44 Fallout Shelters
    22. 16.45 Transportation Impact Fee for New Nonresidential Develop…
    23. 16.46 Approval of Projects with Impacts on Traffic in the San …
    24. 16.47 Reserved
    25. 16.48 Reserved
    26. 16.49 Historic Preservation
    27. 16.50 Reserved
    28. 16.52 Flood Hazard Regulations
    29. 16.56 Handicapped Access Regulations - Appeal
    30. 16.57 In-Lieu Parking Fee for New Nonresidential Development i…
    31. 16.58 Development Impact Fees
    32. 16.59 Citywide Transportation Impact Fee
    33. 16.60 Charleston Arastradero Corridor Pedestrian and Bicyclist…
    34. 16.61 Public Art for Private Developments
    35. 16.62 Expired Permits for Residential Construction and Demolit…
    36. 16.63 Small Residential Rooftop Solar Energy Systems
    37. 16.64 Development Fee and In-lieu Payment Administration
    38. 16.65 Citywide Affordable Housing Requirements
    39. 16.66 Hauled Liquid Waste
    40. Chapter 16.04 — CALIFORNIA BUILDING CODE, CALIFORNIA CODE OF
    41. Chapter 16.05 — CALIFORNIA MECHANICAL CODE, CALIFORNIA CODE OF
    42. Chapter 16.08 — CALIFORNIA PLUMBING CODE, CALIFORNIA CODE OF
    43. Chapter 16.09 — SEWER USE ORDINANCE
    44. Chapter 16.10 — PRIVATE SEWAGE DISPOSAL SYSTEMS
    45. Chapter 16.11 — STORMWATER POLLUTION PREVENTION
    46. Part 2 — General Provisions
    47. Part 3 — Development Projects
    48. Part 10 — Copper Controls
    49. Part 3 — Development Projects
    50. Part 4 — Required Best Management Practices for All Dischargers
    51. Part 5 — Illicit Discharge Detection and Elimination and Mobil…
    52. Part 6 — Pesticides Toxicity Control
    53. Part 7 — Trash Load Reductions
    54. Part 8 — Mercury Controls
    55. Part 9 — Polychlorinated Biphenyls (PCBs) Controls
    56. Part 10 — Copper Controls
    57. Chapter 16.12 — RECYCLED WATER
    58. Chapter 16.13 — REQUIREMENTS FOR FOOD FACILITIES RELATED TO WA…
    59. Part 6 — Rooftop Grease Containment System Requirements
    60. Part 11 — Food Facility Closure or Ownership Change
    61. Part 3 — Authority to Inspect and Enforce
    62. Part 4 — Prohibited Discharges, Devices, and Connections
    63. Part 5 — Grease Control Device Requirements
    64. Part 6 — Rooftop Grease Containment System Requirements
    65. Part 7 — Waste Oil Management Requirements
    66. Part 8 — Spill Response Requirements
    67. Part 9 — Best Management Practices for Existing Facilities
    68. Part 10 — Mobile Food Facilities
    69. Part 11 — Food Facility Closure or Ownership Change
    70. Chapter 16.14 — CALIFORNIA GREEN BUILDING STANDARDS CODE,
    71. Part 1 — General
    72. Chapter 4 — RESIDENTIAL
    73. Chapter 7 — INSTALLER AND SPECIAL
    74. Part 7 — Local Modifications to
    75. Chapter 5 — NONRESIDENTIAL
    76. Part 9 — Local Modifications to
    77. Part 1 — General
    78. Chapter 1 — ADMINISTRATION
    79. Chapter 2 — DEFINITIONS
    80. Chapter 3 — GREEN BUILDING
    81. Chapter 4 — RESIDENTIAL MANDATORY MEASURES
    82. Chapter 7 — INSTALLER AND SPECIAL INSPECTOR QUALIFICATIONS
    83. Part 7 — Local Modifications to
    84. Chapter 5 — NONRESIDENTIAL MANDATORY MEASURES
    85. Part 9 — Local Modifications to
    86. Chapter 16.16 — CALIFORNIA ELECTRICAL CODE, CALIFORNIA CODE OF
    87. ▸Chapter 16.17 — CALIFORNIA ENERGY CODE, CALIFORNIA CODE OF
    88. Chapter 16.19 — CALIFORNIA HISTORICAL BUILDING CODE, CALIFORNI…
    89. Chapter 16.20 — SIGNS
    90. Chapter 16.20 — Table 1
    91. Chapter 16.20 — Table 2
    92. Chapter 16.20 — Table 2
    93. Chapter 16.20 — Table 3
    94. Chapter 16.24 — FENCES
    95. Chapter 16.28 — GRADING AND EROSION AND SEDIMENT CONTROL
    96. Chapter 16.32 — MOVING AND RELOCATING BUILDINGS
    97. Chapter 16.36 — HOUSE NUMBERING
    98. Chapter 16.38 — CERTIFICATE OF USE AND OCCUPANCY FOR COMMUNITY
    99. Chapter 16.40 — UNSAFE BUILDINGS
    100. Chapter 16.44 — FALLOUT SHELTERS
    101. Chapter 16.45 — TRANSPORTATION IMPACT FEE FOR NEW NONRESIDENTIAL
    102. Chapter 16.46 — APPROVAL OF PROJECTS WITH IMPACTS ON TRAFFIC I…
    103. Chapter 16.48 — RESERVED
    104. Chapter 16.49 — HISTORIC PRESERVATION
    105. Chapter 16.50 — RESERVED
    106. Chapter 16.52 — FLOOD HAZARD REGULATIONS
    107. Chapter 16.56 — HANDICAPPED ACCESS REGULATIONS - APPEAL
    108. Chapter 16.57 — IN-LIEU PARKING FEE FOR NEW NONRESIDENTIAL DEV…
    109. Chapter 16.58 — DEVELOPMENT IMPACT FEES
    110. Chapter 16.59 — CITYWIDE TRANSPORTATION IMPACT FEE
    111. Chapter 16.60 — CHARLESTON ARASTRADERO CORRIDOR PEDESTRIAN
    112. Chapter 16.61 — PUBLIC ART FOR PRIVATE DEVELOPMENTS
    113. Chapter 16.62 — EXPIRED PERMITS FOR RESIDENTIAL CONSTRUCTION AND
    114. Chapter 16.63 — SMALL RESIDENTIAL ROOFTOP SOLAR ENERGY SYSTEMS
    115. Chapter 16.64 — DEVELOPMENT FEE AND IN-LIEU PAYMENT ADMINISTRA…
    116. Chapter 16.66 — HAULED LIQUID WASTE
  15. Title 17 — HAZARDOUS MATERIALS STORAGE
  16. Title 18 — ZONING
  17. Title 19 — MASTER PLAN
  18. Article 7 — AUTHORITY FOR AND SCOPE OF MASTER OR GENERAL PLANS.
  19. Article 8 — PROCEDURE FOR ADOPTION OF MASTER OR GENERAL PLAN.
  20. Chapter 19.06 — SPECIFIC PLANS
  21. Chapter 19.10 — COORDINATED AREA PLANS
  22. Title 20 — PRECISE PLANS
  23. Title 21 — SUBDIVISIONS AND OTHER DIVISIONS OF LAND
  24. Title 22 — PARKS

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