CRC · California Residential Code
Equipment minimum efficiency, verification, and labeling (CMC Appendix E energy provisions)
Appendix E requires specified HVAC and refrigeration equipment to meet minimum efficiencies in the Appendix E tables; those efficiencies must be documented by DOE/certification listing, independent test report, or manufacturer data, and many non‑federal units must carry a permanent compliance label.
Last reviewed: July 6, 2026
What the code requires — plain English
The mechanical equipment listed in § E 503.4 must meet the minimum performance shown in the Appendix E minimum-efficiency tables when tested under the specified rating conditions. Equipment efficiencies must be verified by one of the accepted means (DOE/EPACT certification, an accepted certification program, independent laboratory test reports, or manufacturer data) and many non‑NAECA-covered units must carry a permanent manufacturer label stating compliance with ASHRAE 90.1. See § E 503.4 and the cross-referenced tables in § E 503.7 for scope and procedural detail.
The single most important rule: mechanical equipment listed in Appendix E must meet the minimum efficiencies in the Appendix E tables and those efficiencies must be verified and, where required, permanently labeled. § E 503.4 and § E 503.7 are the controlling sections.
Requirements in detail
Scope — what equipment is covered
- Equipment listed in the tables referenced by § E 503.4 (Table E 503.7.1(1) through Table E 503.7.1(20)) is subject to the minimum-efficiency requirements.
- Duct insulation and pipe insulation minimums are in § E 503.7.2 and § E 503.7.3 respectively.
Minimum-performance requirement (what “meet the tables” means)
- Equipment must meet all stated rating conditions in the applicable table for its equipment category; if multiple rating conditions are listed, the unit must satisfy each stated requirement unless a table footnote explicitly exempts it. § E 503.4.
- Equipment covered under the Federal Energy Policy Act of 1992 (EPACT) is treated specially: EPACT-covered products have no minimum requirement for operation at minimum capacity or nonstandard rating conditions (see table footnotes and § E 503.4).
Verification of efficiency ratings — how to prove compliance
Per § E 503.4.3, manufacturer-supplied efficiency information must be verified by one of these methods:
- DOE/EPACT certification for equipment covered by EPACT.
- Product listing in an accepted certification program that includes verification and challenge provisions.
- If a program exists but the product is not listed, then independent laboratory test reports are required.
- If no certification program exists, the manufacturer’s data may be used to support the ratings.
- Where a system is assembled from components (coils, condensing units, etc.) from different manufacturers, the system designer must specify combined component efficiencies demonstrating the assembled system meets the minimums.
Labeling requirements
- Mechanical equipment not covered by NAECA must carry a permanent manufacturer-installed label stating the equipment complies with ASHRAE 90.1, per § E 503.4.4.
- Packaged terminal air conditioners (PTAC) below certain sleeve dimensions (cross-sectional area < 670 in² or less than 16 in high or 42 in wide) must be factory labeled as “Manufactured for nonstandard‑size applications only: Not to be installed in new construction projects.” See § E 503.4.4.1 for the PTAC labeling special case.
Where to find the numeric minimums and insulation R-values
- Numerical minimums for each equipment category are listed in the tables referenced by § E 503.7.1 (Table E 503.7.1(1) through Table E 503.7.1(20)). Duct insulation values are in Table E 503.7.2, and pipe insulation values are in Table E 503.7.3(1) and Table E 503.7.3(2). The code requires you to consult those tables to determine the specific numeric minimums for your equipment. § E 503.7 and § E 503.7.1.
Decision-relevant quick reference table
| Decision question | Where to look in the Code | Code Reference |
|---|---|---|
| Is my equipment category listed and subject to minimums? | Appendix E equipment tables list covered categories | § E 503.4 / § E 503.7.1 |
| Which table contains the numeric minimum efficiency for a unitary air-conditioner or condensing unit? | Table E 503.7.1(1) | § E 503.7.1 (Table E 503.7.1(1)) |
| How must manufacturer performance claims be verified? | Verification methods listed (DOE, certification program, lab report, manufacturer data) | § E 503.4.3 |
| Is labeling required? | Permanent manufacturer label for non-NAECA equipment; special PTAC label rule | § E 503.4.4 and § E 503.4.4.1 |
| Where are duct/pipe insulation minimums? | Duct: Table E 503.7.2; Pipe: Table E 503.7.3 series | § E 503.7.2 and § E 503.7.3 |
Exceptions & special cases
- Equipment governed by EPACT: no minimum for operation at minimum capacity or nonstandard conditions; check table footnotes and § E 503.4.
- Equipment not listed in the E 503.7 tables may still be used; the code permits unlisted equipment subject to verification rules in § E 503.4.2.
- If you choose the Simplified Approach (§ E 503.3) for compliance, you are not required to comply with § E 503.4 (see the exception to § E 503.2.2(1)). That means the verification/labeling requirements in § E 503.4 are not enforced when the simplified path is used.
- Component combinations: when mixing components from different manufacturers the system designer must demonstrate the assembled system meets the table minimums (see § E 503.4.3(5)).
Common mistakes
- Treating federal certification (DOE/NAECA/EPACT) as optional. If a federal program covers the product, the appropriate federal certification path is required for verification — see § E 503.4.3.
- Installing a unit that meets nameplate federal ratings but failing to produce the required certification listing, independent test report, or manufacturer data at submittal — verification must be provable under § E 503.4.3.
- Forgetting to label non‑NAECA equipment. If a piece of mechanical equipment is not NAECA-covered, it must carry the permanent ASHRAE‑90.1 compliance label per § E 503.4.4.
- Assuming table applicability without checking footnotes and rating conditions. Many minimums are conditional on rating temperatures, capacities, or test standards; read the applicable Table E 503.7.1(x) and its footnotes. § E 503.7.1.
- Using manufacturer data alone when an accepted certification program exists and the product is unlisted — the code requires either listing in the program or independent lab verification per § E 503.4.3(3).
Worked example — boiler selection and verification (concrete)
Scenario: You are specifying a gas‑fired steam boiler with rated input = 800,000 Btu/h for a commercial laundry.
Step 1 — locate the equipment category:
- Steam boilers are listed in the Appendix E equipment tables (see § E 503.7.1 and the boilers table).
Step 2 — find the numeric minimum for that size and fuel:
- For gas‑fired steam boilers with rated input ≥ 300,000 Btu/h and ≤ 2,500,000 Btu/h, the Table excerpt in the code shows a minimum thermal efficiency listed as 77% Et for certain columns and 79% Et in others (consult the full Table E 503.7.1(6) in the code for the exact column that applies to your installation and any applicable notes). § E 503.7.1 and the boilers table excerpt illustrate these numeric values.
Step 3 — verification to submit with permit documents:
- If the boiler type is covered by DOE/EPACT test/cert programs, provide the DOE certification listing (per § E 503.4.3(1)). If not listed in an accepted certification program, provide an independent laboratory test report demonstrating the unit meets the stated thermal efficiency at the rated conditions (per § E 503.4.3(3) and (4)).
Step 4 — labeling and owner documents:
- If the boiler is not covered by NAECA, ensure the manufacturer affixes a permanent label indicating compliance with ASHRAE 90.1 per § E 503.4.4. Include the equipment submittal data and operating/maintenance manuals required under § E 503.6.3 with the project submittal.
Note: The example lists the numeric boiler efficiency values that appear in the code excerpt; for other equipment categories (for example, SEER/EER requirements for unitary air conditioners), you must consult the specific Table E 503.7.1(x) entry for the numeric minimums — those numeric values are not repeated here in full. § E 503.7.1.
Related provisions (quick links)
- § E 503.2 — Compliance paths and when § E 503.4 applies (exceptions for simplified approach).
- § E 503.3 — Simplified Approach building compliance path (when § E 503.4 is not required).
- § E 503.6 — Submittals, labeling of material and equipment, owner manuals (related verification/documentation requirements).
- § E 503.7 — Tables: E 503.7.1 equipment efficiency tables, E 503.7.2 duct insulation, E 503.7.3 pipe insulation.
- § E 503.4.1 — Water-cooled centrifugal chilling packages and special rating/test conditions.
Code references
Grounded in the retrieved California Residential Code — click a citation to read the verbatim passage:
CRC § 503.5.14. High relevance — show source text
(20) The system shall comply with the door switch requirements of Section E 503.5.14. [ASHRAE 90.1:6.3.2]
E 503.3.2 Climate Zone Determination. Climate zones identified in this appendix shall be determined in accordance with ASHRAE 90.1. For locations in the United States and its territories, the assigned climate zone and, where required, the assigned climate zone letter shall be in accordance with ASHRAE 169.
Exception: Where recorded historical climatic data are available for a construction site, it is permitted to be used to determine compliance where approved by the Authority Having Jurisdiction. [ASHRAE 90.1:5.1.4.1]
E 503.4 Equipment Efficiencies, Verification, and Labeling Requirements. Equipment shown in Table E 503.7.1(1) through Table E 503.7.1(20) shall have a minimum performance at the specified rating conditions when tested in accordance with the specified test procedure. Where multiple rating conditions or performance requirements are provided, the equipment shall satisfy all stated requirements unless otherwise exempted by footnotes in the table. Equipment covered under the Federal Energy Policy Act of 1992 (EPACT) shall have no minimum efficiency requirements for operation at minimum capacity or other than standard rating conditions. Equipment used to provide service water-heating functions as part of a combination system shall satisfy all stated requirements for the appropriate space heating or cooling category.
Tables are as follows:
(1) Table E 503.7.1(1), “Electrically Operated Unitary Air Conditioners and Condensing Units—Minimum Efficiency Requirements” (2) Table E 503.7.1(2), “Electrically Operated Air-Cooled Unitary Heat Pumps—Minimum Efficiency Requirements”
(3) Table E 503.7.1(3), “Water-Chilling Packages—Minimum Efficiency Requirements” (See Section E 503.4.1 for water-cooled centrifugal water-chilling packages that are designed to operate at nonstandard conditions.) (4) Table E 503.7.1(4), “Electrically Operated Packaged Terminal Air Conditioners, Packaged Terminal Heat Pumps, Single-Package Vertical Air Conditioners, Single-Package Vertical Heat Pumps, Room Air Conditioners, and Room Air Conditioner Heat Pumps—Minimum Efficiency Requirements” (5) Table E 503.7.1(5), “Warm-Air Furnaces and Combination Warm-Air Furnaces/Air-Conditioning Units, WarmAir Duct Furnaces, and Unit Heaters—Minimum Efficiency Requirements”
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APPENDIX E
(6) Table E 503.7.1(6), “Gas- and Oil-Fired Boilers—Minimum Efficiency Requirements” (7) Table E 503.7.1(7), “Performance Requirements for Heat-Rejection Equipment—Minimum Efficiency Requirements” (8) Table E 503.7.1(8), “Electrically Operated VariableRefrigerant-Flow Air Conditioners—Minimum Efficiency Requirements”
(9) Table E 503.7.1(9), “Electrically Operated VariableRefrigerant-Flow and Applied Heat Pumps—Minimum Efficiency Requirements”
CRC § 1.02024 High relevance — show source text
Kadj = A x B = 1.02024 FLajd = 0.5600/1.02024 = 0.5489 kW/ton PLVadj = 0.5000/1.02024 = 0.4901 kW/ton
[ASHRAE 90.1:6.4.1.2.1]
For SI units: 1 metric ton = 1000 kg, 1000 British thermal units per
hour = 0.293 kW, 1 gallon per minute = 0.06 L/s, °C = (°F-32)/1.8
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APPENDIX E
E 503.4.1.1 Positive Displacement (air- and water-cooled) Chilling Packages. Equipment with an evaporator leaving fluid temperature higher than 32.00°F (0.00°C) and water-cooled positive displacement chilling packages with a condenser leaving fluid temperature below 115.00°F (46.11°C) shall show compliance with Table E 503.7.1(3) when tested or certified with water at standard rating conditions, in accordance with the referenced test procedure. [ASHRAE 90.1:6.4.1.2.2]
E 503.4.2 Equipment not Listed. Equipment not listed in the tables referenced in Section E 503.4 and Section E 503.4.1 shall be permitted to be used. [ASHRAE 90.1:6.4.1.4]
E 503.4.3 Verification of Equipment Efficiencies. Equipment efficiency information supplied by manufacturers shall be verified in accordance with one of the following:
(1) Equipment covered under EPACT shall be in accordance with U.S. Department of Energy certification requirements.
(2) Where a certification program exists for a covered product, and it includes provisions for verification and challenge of equipment efficiency ratings, then the product shall be listed in the certification program.
(3) Where a certification program exists for a covered product, and it includes provisions for verification and challenge of equipment efficiency ratings, but the product is not listed in the existing certification program, the ratings shall be verified by an independent laboratory test report.
(4) Where no certification program exists for a covered product, the equipment efficiency ratings shall be supported by data furnished by the manufacturer.
(5) Where components such as indoor or outdoor coils from different manufacturers are used, the system designer shall specify component efficiencies whose combined efficiency is in accordance with the minimum equipment efficiency requirements in Section E 503.4 through Section E 503.4.4.1. [ASHRAE 90.1:6.4.1.5]
E 503.4.4 Mechanical Equipment Labeling. Mechanical equipment that is not covered by the U.S. National Appliance Energy Conservation Act (NAECA) of 1987 shall carry a permanent label installed by the manufacturer stating that the equipment is in accordance with the requirements of ASHRAE 90.1. [ASHRAE 90.1:6.4.1.6.1]
CRC § 503.4.3 High relevance — show source text
E 503.4.3 Verification of Equipment Efficiencies. Equipment efficiency information supplied by manufacturers shall be verified in accordance with one of the following:
(1) Equipment covered under EPACT shall be in accordance with U.S. Department of Energy certification requirements.
(2) Where a certification program exists for a covered product, and it includes provisions for verification and challenge of equipment efficiency ratings, then the product shall be listed in the certification program.
(3) Where a certification program exists for a covered product, and it includes provisions for verification and challenge of equipment efficiency ratings, but the product is not listed in the existing certification program, the ratings shall be verified by an independent laboratory test report.
(4) Where no certification program exists for a covered product, the equipment efficiency ratings shall be supported by data furnished by the manufacturer.
(5) Where components such as indoor or outdoor coils from different manufacturers are used, the system designer shall specify component efficiencies whose combined efficiency is in accordance with the minimum equipment efficiency requirements in Section E 503.4 through Section E 503.4.4.1. [ASHRAE 90.1:6.4.1.5]
E 503.4.4 Mechanical Equipment Labeling. Mechanical equipment that is not covered by the U.S. National Appliance Energy Conservation Act (NAECA) of 1987 shall carry a permanent label installed by the manufacturer stating that the equipment is in accordance with the requirements of ASHRAE 90.1. [ASHRAE 90.1:6.4.1.6.1]
E 503.4.4.1 Packaged Terminal Air Condi- tioners. Nonstandard-size packaged terminal air conditioners and heat pumps with existing sleeves having an external wall opening of less than 16 inches (406 mm) high or less than 42 inches (1067 mm) wide and having a cross-sectional area less than 670 square inches (0.432 m [2] ) shall be factory labeled as follows:
Manufactured for nonstandard-size applications only: Not to be installed in new construction projects. [ASHRAE 90.1:6.4.1.6.2]
E 503.4.5 Load Calculations. Heating and cooling system design loads for the purpose of sizing systems and equipment shall be determined in accordance with ASHRAE/ACCA 183. [ASHRAE 90.1:6.4.2.1]
E 503.4.5.1 Pump Head. Pump differential pressure (head) for the purpose of sizing pumps shall be determined in accordance with generally accepted engineering standards and handbooks acceptable to the Authority Having Jurisdiction. The pressure drop through each device and pipe segment in the critical circuit at design conditions shall be calculated.
[ASHRAE 90.1:6.4.2.2]
E 503.4.6 Zone Thermostatic Controls. The supply of heating and cooling energy to each zone shall be individually controlled by thermostatic controls responding to temperature within the zone. For the purposes of Section E 503.4.6, a dwelling unit shall be permitted to be considered a single zone.
Exceptions: Independent perimeter systems that are designed to offset only building envelope loads shall be permitted to serve one or more zones also served by an interior system, provided that:
CRC § 503.4.6.3.1 High relevance — show source text
(11) Systems serving residential spaces other than hotel/motel guest rooms shall comply with Section E 503.4.6.3.1 and Section E 503.4.6.3.2 except for electric resistance heaters rated at 5000 Btu/h (1.5 kW) or less with a readily accessible manual control that lowers the set point or turns the unit off.
(12) Systems serving hotel/motel guest rooms shall comply with Section E 503.4.6.3.5.
(13) Except for piping within manufacturer’s units, HVAC piping shall be insulated in accordance with Table E 503.7.3(1) and Table E 503.7.3(2). Insulation exposed to weather shall be suitable for outdoor service, e.g., protected by aluminum, sheet metal, painted canvas, or plastic cover. Cellular foam insulation shall be protected as above or painted with a coating that is water retardant and provides shielding from solar radiation.
(14) Ductwork and plenums shall be insulated in accordance with Table E 503.7.2 and shall be sealed in
accordance with Section E 503.4.7.2.
(15) Construction documents shall require a ducted system to be air balanced in accordance with industryaccepted procedures.
(16) Outdoor air intake and exhaust systems shall comply with Section E 503.4.6.4 through Section E 503.4.6.5.
(17) Where separate heating and cooling equipment serves the same temperature zone, thermostats shall be interlocked to prevent simultaneous heating and cooling.
(18) Systems with a design supply air capacity more than 10 000 ft [3] /min (4.7195 m [3] /s) shall have optimum start controls.
(19) The system shall comply with the demand control ventilation requirements of Section E 503.4.6.9, occupied-standby controls in Section E 503.5.6.8, and the ventilation design requirements of Section E 503.5.6.7.
(20) The system shall comply with the door switch requirements of Section E 503.5.14. [ASHRAE 90.1:6.3.2]
E 503.3.2 Climate Zone Determination. Climate zones identified in this appendix shall be determined in accordance with ASHRAE 90.1. For locations in the United States and its territories, the assigned climate zone and, where required, the assigned climate zone letter shall be in accordance with ASHRAE 169.
Exception: Where recorded historical climatic data are available for a construction site, it is permitted to be used to determine compliance where approved by the Authority Having Jurisdiction. [ASHRAE 90.1:5.1.4.1]
E 503.4 Equipment Efficiencies, Verification, and Labeling Requirements. Equipment shown in Table E 503.7.1(1) through Table E 503.7.1(20) shall have a minimum performance at the specified rating conditions when tested in accordance with the specified test procedure. Where multiple rating conditions or performance requirements are provided, the equipment shall satisfy all stated requirements unless otherwise exempted by footnotes in the table. Equipment covered under the Federal Energy Policy Act of 1992 (EPACT) shall have no minimum efficiency requirements for operation at minimum capacity or other than standard rating conditions. Equipment used to provide service water-heating functions as part of a combination system shall satisfy all stated requirements for the appropriate space heating or cooling category.
CRC § 503.1.3.3 Medium relevance — show source text
E 503.1.3.3 Ductwork. New and replacement ductwork shall comply with Section E 503.4.7.1 through Section E 503.4.7.2.1. [ASHRAE 90.1:6.1.1.3.4]
E 503.1.3.4 Piping. New and replacement piping shall comply with Section E 503.4.7.1.
Exceptions:
(1) For equipment that is being modified or repaired but not replaced, provided that such modifications or repairs will not result in an increase in the annual energy consumption of the equipment using the same energy type.
(2) Where a replacement or alteration of equipment requires extensive revisions to other systems, equipment, or elements of a building, and such replaced or altered equipment is a like-for-like replacement.
(3) For a refrigerant change of existing equipment.
(4) For the relocation of existing equipment.
(5) For ducts and piping where there is insufficient space or access to comply with these requirements. [ASHRAE 90.1:6.1.1.3.5] E 503.2 Compliance Paths. Mechanical equipment and systems providing heating, cooling, ventilating, or refrigeration shall comply with Section E 503.2.1 and Section E 503.2.2. [ASHRAE 90.1:6.2]
E 503.2.1 Requirements for All Compliance Paths. Mechanical equipment and systems shall comply with the following:
(1) Section E 503.0, “General”
(2) Section E 503.4, “Equipment Efficiencies, Verification, and Labeling Requirements”
(3) Section E 503.6, “Submittals”
(4) Section E 503.7, “Minimum Equipment Efficiency Tables.” [ASHRAE 90.1:6.2.1]
E 503.2.2 Additional Requirements. Mechanical equipment and systems shall comply with one of the following:
(1) Section E 503.3, “Simplified Approach Building Compliance Path for HVAC Systems”
Exception: When compliance is shown using Section E 503.2.2(1), compliance with Section E 503.4 is not required.
(2) Section E 503.5, “Prescriptive Compliance Path”
Exception: HVAC systems only serving the heating, cooling, or ventilating needs of a computer room with IT equipment load greater than 10 kW (34 000 Btu/h) shall be permitted to comply with Section E 503.4, “Equipment Efficiencies, Verification, and Labeling Requirements” and Section E
503.8, “Alternative Compliance Path, Computer Room Systems.” [ASHRAE 90.1:6.2.2] E 503.3 Simplified Approach Building Compliance Path for HVAC Systems. The simplified approach shall be an optional path for compliance where the following conditions are met:
(1) The building is not more than two stories in height. (2) Gross floor area is less than 25 000 square feet (2322.6 m [2] ).
(3) The HVAC system in the building is in accordance with the requirements listed in Section E 503.3.1. [ASHRAE 90.1:6.3.1] E 503.3.1 Criteria. The HVAC system shall comply with all of the following criteria:
(1) The system serves a single HVAC zone.
CRC § 90.1 Medium relevance — show source text
(5) A complete narrative of how each system is intended to operate, including suggested setpoints. [ASHRAE 90.1:6.7.3.2] E 503.6.5.3 System Balancing. Construction documents shall require that HVAC systems be balanced in accordance with generally accepted engineering standards. Construction documents shall require that a written balance report be provided to the building owner or the designated representative of the building owner for HVAC systems serving a total conditioned space or zone exceeding 5000 square feet (464.52 m [2] ). {ASHRAE 90.1:6.7.3.3.1}
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APPENDIX E
»E 503.6.5.3.1 Air System Balancing. Air systems shall be balanced in a manner to first minimize throttling losses. Then, for fans with fan system power greater than 1 hp (0.7 kW), fan speed shall be adjusted to meet design flow conditions. [ASHRAE 90.1:6.7.3.3.2]
E 503.6.5.3.2 Hydronic System Balanc- ing. Hydronic systems shall be proportionately balanced in a manner to first minimize throt tling losses; then the pump impeller shall be trimmed or pump speed shall be adjusted to meet design flow conditions.
Exceptions: Impellers need not be trimmed nor pump speed adjusted.
(1) For pumps with pump motors of 10 hp (7.5 kW) or less.
(2) Where throttling results is not greater than 5 percent of the nameplate horsepower draw, or 3 hp (2.2 kW), whichever is greater, above that required where the impeller was trimmed. [ASHRAE 90.1:6.7.3.3]
E 503.6.5.4 Minimum Level of Commission.
Commissioning shall be performed for HVAC systems in accordance with Level 1, Basic Commissioning of the SMACNA HVAC Systems Commissioning Manual. (See Section E 801.0 for additional information on HVAC system commissioning)
E 503.7 Minimum Equipment Efficiency Tables. The minimum efficiency requirements for equipment shall comply with Section E 503.7.1; duct insulation shall comply with Section E 503.7.2, and pipe insulation shall comply with Section E 503.7.3.
E 503.7.1 Minimum Efficiency Requirement Listed Equipment – Standard Rating and Oper- ating Conditions. The minimum efficiency requirements for equipment shall comply with Table E 503.7.1(1) through Table E 503.7.1(20).
E 503.7.2 Duct Insulation Tables. Duct insulation
shall comply with Table E 503.7.2.
E 503.7.3 Pipe Insulation Tables. Pipe insulation shall comply with Table E 503.7.3(1) and Table E 503.7.3(2).
CRC § 503.1.2 Medium relevance — show source text
E 503.1.2 Additions to Existing Buildings. Mechanical equipment and systems serving the heating, cooling, ventilating, or refrigeration needs of additions to existing buildings shall be in accordance with the requirements of this section as described in Section E 503.2.
Exception: Where HVACR to an addition is provided by existing HVACR systems and equipment, such existing systems and equipment shall not be required to be in accordance with this appendix. A new system or equipment installed shall be in accordance with specific requirements applicable to those systems and equipment.
[ASHRAE 90.1:6.1.1.2]
E 503.1.3 Alterations to Heating, Ventilating, Air- Conditioning, and Refrigeration in Existing Buildings. New HVACR equipment as a direct replacement of existing HVACR equipment shall comply with the following sections as applicable for the equipment being replaced:
(1) Section E 503.3 “Simplified Approach Option for HVAC Systems”
(2) Section E 503.4 “Equipment Efficiencies, Verification, and Labeling Requirements”
(3) Section E 503.4.6 “Zone Thermostatic Controls”
(4) Section E 503.4.6.2 “Set-point Overlap Restrictions”
(5) Section E 503.4.6.3 “Off-Hour Controls” except for Section E 503.4.6.3.4, “Zone Isolation”
(6) Section E 503.4.6.4 “Ventilation System Controls”
(7) Section E 503.4.6.8 “Freeze Protection and Snow/Ice Melting Systems”
(8) Section E 503.4.6.9 “Ventilation Controls for HighOccupancy Areas” only for single-zone equipment
(9) Section E 503.4.6.11 “Heated or Cooled Vestibules”
(10)Section E 503.4.8 “Walk-In Coolers and Walk-In Freezers”
(11)Section E 503.5.1 “Air Economizers” for units located outdoors
(12)Section E 503.5.3 “Integrated Economizer Control”
(13)Section E 503.5.4 “Economizer Heating System Impact”
(14)Section E 503.5.6.1.2 “Fan Efficiency”
(15)Section E 503.5.6.2 “Supply Fan Airflow Control”
(16)Section E 503.5.6.5 “Fractional Horsepower (Kilowatt) Fan Motors”
(17)Section E 503.5.7 “Boiler Turndown”
(18)Section E 503.5.7.3 “Chiller and Boiler Isolation”
(19)Section E 503.5.8.1 “Fan Speed Control.” [ASHRAE 90.1:6.1.1.3.1]
E 503.1.3.1 New Cooling Systems. New cooling systems installed to serve previously uncooled spaces shall be in accordance with this section as described in Section E 503.2. [ASHRAE 90.1:6.1.1.3.2]
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APPENDIX E
CRC § 160.3 Medium relevance — show source text
ii. For duct wrap, installed thickness shall be assumed to be 75 percent (25 percent compression) of nominal thickness.
iii. For factory-made flexible air ducts, the installed thickness shall be determined by dividing the difference between the actual outside diameter and nominal inside diameter by two. F. Duct labeling. Insulated flexible duct products installed to meet this requirement shall include labels, in maximum intervals of 3 feet, showing the thermal performance R- value for the duct insulation itself (excluding air films, vapor retarder or other duct components), based on the tests in Section 160.3(b)5D and the installed thickness determined by Section 160.3(b)5Eiii. G. Backdraft dampers. All fan systems, regardless of volumetric capacity, that exchange air between the building conditioned space and the outside of the building shall be provided with backdraft or automatic dampers to prevent unintended air leakage through the fan system when the fan system is not operating. H. Gravity ventilation dampers. All gravity ventilating systems that serve conditioned space shall be provided with either automatic or readily accessible, manually operated dampers in all openings to the outside except combustion inlet and outlet air openings and elevator shaft vents. I. Protection of insulation. Insulation shall be protected from damage, including that due to sunlight, moisture, equipment maintenance and wind but not limited to the following: Insulation exposed to weather shall be suitable for outdoor service (e.g., protected by aluminum, sheet metal, painted canvas or plastic cover). Cellular foam insulation shall be protected as above or painted with a coating that is water retardant and provides shielding from solar radiation that can cause degradation of the material. J. Porous inner core flex duct. Flexible ducts having porous inner cores shall have a nonporous layer or air barrier between the inner core and the outer vapor barrier. K. Duct system sealing and leakage testing. When space-conditioning systems utilize forced air duct systems to supply conditioned air to an individual dwelling unit, the ducts shall be sealed, as confirmed through field verification and diagnostic testing, in accordance with all applicable procedures specified in Reference Residential Appendix RA3.1. Air handler airflow for calculation of duct leakage rate compliance targets shall be determined according to methods specified in Reference Residential Appendix RA3.1.4.2. For multifamily dwellings with the air-handling unit installed and the ducts connected directly to the air handler, regardless of duct system location: i. The total leakage of the duct system shall not exceed 12 percent of the air handler airflow as determined utilizing the procedures in Reference Residential Appendix Section RA3.1.4.3.1; or ii. The duct system leakage to outside shall not exceed 6 percent of the air handler airflow as determined utilizing the procedures in Reference Residential Appendix Section RA3.1.4.3.4.
- Exception 1 to Section 160.3(b)5K: The field verification and ECC-Provider data registry requirements of Reference Residential Appendix RA2 and RA3 are not required for multifamily dwelling units in buildings four
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on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
MULTIFAMILY BUILDINGS—MANDATORY REQUIREMENTS
habitable stories and greater. The installer shall certify that diagnostic testing was performed in accordance with the applicable procedures. Exception 2 to Section 160.3(b)5K: Multifamily dwelling units in buildings four habitable stories and greater in Climate Zones 1, 3, 5 and 7. L.
CRC § 90.1 Medium relevance — show source text
[ASHRAE 90.1:6.4.3.7] E 502.10.5 Other Controls. Where setback, zoned, humidity and cooling controls and equipment are provided, they shall be designed and installed in accordance with Section E 502.10 through Section E 502.10.3.1.
[ASHRAE 90.2-2007:6.10.3.3]
E 502.11 Whole House Fans. Whole house exhaust fans
shall have insulated louvers or covers which close where the
fan is off. Covers or louvers shall have an insulation value of not less than R-4.2, and shall be installed in accordance with the manufacturer’s installation instructions. The attic openings shall be sufficient to accommodate the ventilation capacity of the whole house fan. The operation of the whole house fan shall be considered in determining the adequacy of providing combustion air in accordance with this code. E 502.12 Dampers. Dampers shall be installed to close off outdoor air inlets and exhaust outlets where the ventilation system is not operating.
E 503.0 Heating, Ventilation, and Air-Conditioning – Other than Low-Rise Residential Buildings. E 503.1 General. The heating, ventilation, and air-conditioning in buildings, other than single-family houses, multi-family structures of not more than three stories above grade, and modular houses, shall be in accordance with Section E 503.0.
E 503.1.1 New Buildings. Mechanical equipment and systems serving the heating, cooling, ventilating, or refrigeration needs of new buildings shall comply with the requirements of this section as described in Section E 503.2. [ASHRAE 90.1:6.1.1.1]
E 503.1.2 Additions to Existing Buildings. Mechanical equipment and systems serving the heating, cooling, ventilating, or refrigeration needs of additions to existing buildings shall be in accordance with the requirements of this section as described in Section E 503.2.
Exception: Where HVACR to an addition is provided by existing HVACR systems and equipment, such existing systems and equipment shall not be required to be in accordance with this appendix. A new system or equipment installed shall be in accordance with specific requirements applicable to those systems and equipment.
[ASHRAE 90.1:6.1.1.2]
E 503.1.3 Alterations to Heating, Ventilating, Air- Conditioning, and Refrigeration in Existing Buildings. New HVACR equipment as a direct replacement of existing HVACR equipment shall comply with the following sections as applicable for the equipment being replaced:
(1) Section E 503.3 “Simplified Approach Option for HVAC Systems”
(2) Section E 503.4 “Equipment Efficiencies, Verification, and Labeling Requirements”
(3) Section E 503.4.6 “Zone Thermostatic Controls”
(4) Section E 503.4.6.2 “Set-point Overlap Restrictions”
(5) Section E 503.4.6.3 “Off-Hour Controls” except for Section E 503.4.6.3.4, “Zone Isolation”
(6) Section E 503.4.6.4 “Ventilation System Controls”
(7) Section E 503.4.6.8 “Freeze Protection and Snow/Ice Melting Systems”
CRC § 503.7 Medium relevance — show source text
(4) Section E 503.7, “Minimum Equipment Efficiency Tables.” [ASHRAE 90.1:6.2.1]
E 503.2.2 Additional Requirements. Mechanical equipment and systems shall comply with one of the following:
(1) Section E 503.3, “Simplified Approach Building Compliance Path for HVAC Systems”
Exception: When compliance is shown using Section E 503.2.2(1), compliance with Section E 503.4 is not required.
(2) Section E 503.5, “Prescriptive Compliance Path”
Exception: HVAC systems only serving the heating, cooling, or ventilating needs of a computer room with IT equipment load greater than 10 kW (34 000 Btu/h) shall be permitted to comply with Section E 503.4, “Equipment Efficiencies, Verification, and Labeling Requirements” and Section E
503.8, “Alternative Compliance Path, Computer Room Systems.” [ASHRAE 90.1:6.2.2] E 503.3 Simplified Approach Building Compliance Path for HVAC Systems. The simplified approach shall be an optional path for compliance where the following conditions are met:
(1) The building is not more than two stories in height. (2) Gross floor area is less than 25 000 square feet (2322.6 m [2] ).
(3) The HVAC system in the building is in accordance with the requirements listed in Section E 503.3.1. [ASHRAE 90.1:6.3.1] E 503.3.1 Criteria. The HVAC system shall comply with all of the following criteria:
(1) The system serves a single HVAC zone.
(2) The equipment shall comply with the variable flow requirements of Section E 503.5.6.2.
(3) Cooling (where any) shall be provided by a unitary packaged or split-system air conditioner that is either air-cooled or evaporatively cooled, with efficiency that is in accordance with the requirements shown in Table E 503.7.1(1) for air conditioners, Table E 503.7.1(2) for heat pumps, or Table E 503.7.1(4) for packaged terminal and room air conditioners and heat pumps for the applicable equipment category.
(4) The system shall have an air economizer in accordance with Section E 503.5 and Section E 503.4.6.13.
(5) Heating (where any) shall be provided by a unitary packaged or split-system heat pump that is in accordance with the applicable efficiency requirements shown in Table E 503.7.1(2) for heat pumps or Table E 503.7.1(4) for packaged terminal and room air conditioners and heat pumps, a fuel-fired furnace that is in accordance with the applicable efficiency requirements shown in Table E 503.7.1(5) for furnaces, duct furnaces, and unit heaters, an electric resistance heater, or a baseboard system connected to a boiler that is in accordance with the applicable efficiency requirements shown in Table E 503.7.1(6) for boilers.
(6) The system shall comply with the exhaust air energy recovery requirements in accordance with Section E 503.5.10.1.2.
(7) The system shall be controlled by a manual changeover or dual setpoint thermostat.
CRC § 90.1 Medium relevance — show source text
446 2025 CALIFORNIA MECHANICAL CODE
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
APPENDIX E
to permit a determination of compliance by the building official and to indicate compliance with the requirements of this appendix. [ASHRAE 90.1:4.2.2.1] E 503.6.2 Supplemental Information. Supplemental information necessary to verify compliance with this appendix, such as calculations, worksheets, compliance forms, vendor literature, or other data, shall be made available where required by the Authority Having Jurisdiction. [ASHRAE 90.1:4.2.2.2]
E 503.6.3 Manuals. Operating and maintenance information shall be provided to the building owner. This information shall include, but not be limited to, the information specified in Section E 503.6.3.1, Section E 503.6.3.2, and Section E 503.6.5.2. [ASHRAE 90.1:4.2.2.3]
E 503.6.3.1 Required Information. Construction documents shall require that an operating manual and maintenance manual be provided to the building owner. The manuals shall include, at a minimum, the following:
(1) Submittal data stating equipment rating and selected options for each piece of equipment requiring maintenance.
(2) Operation manuals and maintenance manuals for each piece of equipment requiring maintenance. Required routine maintenance actions shall be clearly identified.
(3) Names and addresses of not less than one qualified service agency.
(4) A complete narrative of how each system is intended to operate.
The Authority Having Jurisdiction shall only check to ensure that the construction documents require this information to be transmitted to the owner and should not expect copies of any of the materials.
[ASHRAE 90.1:8.7.3.2]
E 503.6.3.2 Lighting Manuals. Construction documents shall require for all lighting equipment and lighting controls that an operating manual and maintenance manual be provided to the building owner or the designated representative of the building owner within 90 days after the date of system acceptance. These manuals shall include, at a minimum, the following:
(1) Submittal data indicating all selected options for each piece of lighting equipment, including but not limited to lamps, ballasts, drivers, and lighting controls.
(2) Operation and maintenance manuals for each piece of lighting equipment and lighting controls with routine maintenance clearly identified including, as a minimum, a recommended relamping or cleaning program and a schedule for inspecting and recalibrating all lighting controls.
(3) A complete narrative of how each lighting control system is intended to operate including recommended settings. [ASHRAE 90.1:9.7.3.2]
E 503.6.4 Labeling of Material and Equipment. Materials and equipment shall be labeled in a manner that will allow for determination of their compliance with the applicable provisions of this appendix. [ASHRAE 90.1:4.2.3]
E 503.6.5 Completion Requirements. Section E 503.6.5.1 through Section E 503.6.5.4 are mandatory provisions and are necessary to comply with this appendix.
CRC § 503.5.11.3 Medium relevance — show source text
A + B - ( E/M ) ≥ 50% (Equation E 503.5.11.3)
Where:
A = Percentage that the exhaust and makeup airflow rates are capable of being reduced from design conditions.
B = Sensible energy recovery ratio.
E = Exhaust airflow rate through the heat recovery device at design conditions.
M = Makeup airflow rate of the system at design conditions.
(2) VAV laboratory exhaust and room supply systems that are required to have minimum circulation rates to be in accordance with the codes or
accreditation standards shall be capable of and configured to reduce zone exhaust and makeup airflow rates to the regulated minimum circulation values, or the minimum required to maintain pressurization relationship requirements. Systems serving nonregulated zones shall be capable of and configured to reduce exhaust and makeup airflow rates to 50 percent of the zone design values, or the minimum required to maintain pressurization relationship requirements.
(3) Direct makeup (auxiliary) air supply of 75 percent or more of the exhaust airflow rate, heated not more than 2°F (1°C) below room setpoint, cooled to not less than 3°F (2°C) above room setpoint, no humidification added, and no simultaneous heating and cooling are used for dehumidification control. [ASHRAE 90.1:6.5.7.3]
E 503.5.12 Radiant Heating Systems. Radiant heating systems shall be in accordance with Section E 503.5.12.1 through Section E 503.5.12.2.
E 503.5.12.1 Heating Unenclosed Spaces. Radiant heating shall be used when heating is required for unenclosed spaces.
Exception: Loading docks equipped with air curtains. [ASHRAE 90.1:6.5.8.1]
446 2025 CALIFORNIA MECHANICAL CODE
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
APPENDIX E
to permit a determination of compliance by the building official and to indicate compliance with the requirements of this appendix. [ASHRAE 90.1:4.2.2.1] E 503.6.2 Supplemental Information. Supplemental information necessary to verify compliance with this appendix, such as calculations, worksheets, compliance forms, vendor literature, or other data, shall be made available where required by the Authority Having Jurisdiction. [ASHRAE 90.1:4.2.2.2]
E 503.6.3 Manuals. Operating and maintenance information shall be provided to the building owner. This information shall include, but not be limited to, the information specified in Section E 503.6.3.1, Section E 503.6.3.2, and Section E 503.6.5.2. [ASHRAE 90.1:4.2.2.3]
E 503.6.3.1 Required Information. Construction documents shall require that an operating manual and maintenance manual be provided to the building owner. The manuals shall include, at a minimum, the following:
(1) Submittal data stating equipment rating and selected options for each piece of equipment requiring maintenance.
(2) Operation manuals and maintenance manuals for each piece of equipment requiring maintenance. Required routine maintenance actions shall be clearly identified.
(3) Names and addresses of not less than one qualified service agency.
Frequently asked questions
What if my product is not listed in any Appendix E table?
If the product is not listed, Appendix E permits use of unlisted equipment but you must still follow the verification rules in § E 503.4.2 and § E 503.4.3 (manufacturer data, independent test report, or accepted certification as applicable).
Do I always need a permanent label on HVAC equipment?
No — equipment covered by federal NAECA/DOE programs follow federal labeling. Mechanical equipment not covered by NAECA must have a permanent manufacturer label stating compliance with ASHRAE 90.1 as required by § E 503.4.4.
Can I mix coils and condensing units from different manufacturers?
Yes, but when components from different manufacturers are combined the system designer must specify component efficiencies whose combined performance meets Appendix E minimums (see § E 503.4.3(5)).
If my project uses the simplified compliance path, do I need to provide equipment efficiency verification?
If you comply using the Simplified Approach under § E 503.3, compliance with § E 503.4 is not required (exception in § E 503.2.2(1)). Check the simplified path criteria carefully.
Where do I find the numeric SEER/EER/AFUE values?
Numeric minimums for each equipment class are in Table E 503.7.1(1)–(20) and related tables E 503.7.2 (duct) and E 503.7.3 (pipe). Consult the specific table for the precise numeric requirements that apply to your unit and rating condition. § E 503.7.1.
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