Clear definitions for every Title 24 term, acronym, and concept — written for people who build things, not regulators.
Glossary Terms
A
ADU
Accessory Dwelling Unit. A secondary housing unit on a single-family property. ADUs require Title 24 compliance reports separate from the main dwelling.
C
CEC
California Energy Commission. The state agency responsible for creating and enforcing the Title 24 energy standards, among other energy policy functions.
Certificate of Compliance (CF1R)
The primary Title 24 compliance document. Prepared by the energy consultant and submitted with the permit application. Lists the energy features required for compliance.
Climate Zone
California is divided into 16 climate zones based on weather patterns. Title 24 requirements vary by climate zone. Most of Los Angeles falls in Climate Zone 9, with some areas in Zones 8 and 10.
CF2R
Certificate of Installation. Filed by the installing contractor after construction to document that energy features were installed as required by the CF1R (Certificate of Compliance).
CF3R
Certificate of Verification. Filed by a HERS rater after performing field verification of required energy features.
CALGreen
California Green Building Standards Code (Title 24, Part 11). Sets requirements for sustainable construction practices, water efficiency, and material standards. Often submitted alongside Title 24 Part 6 documents.
Cool Roof
A roofing material that reflects more sunlight and absorbs less heat than a standard roof. Title 24 requires cool roofs in certain climate zones and building types.
D
Duct Leakage
The amount of conditioned air that escapes through gaps in a duct system. Title 24 sets maximum allowable duct leakage rates (typically 6% or 15% depending on the compliance path).
E
EnergyPro
State-approved software used by certified energy consultants to perform Title 24 compliance calculations. Required for all non-prescriptive (performance) compliance paths.
EER
Energy Efficiency Ratio. A measure of cooling equipment efficiency at a specific outdoor temperature. Used for commercial equipment efficiency ratings.
H
HERS
Home Energy Rating System. A standardized national energy rating system. In California, HERS raters perform field verification of installed energy features (duct testing, refrigerant charge verification, etc.) as required by Title 24.
HERS Rater
A certified technician who performs field verification and diagnostic testing of energy features in buildings. Required for certain Title 24 compliance measures, particularly residential HVAC and duct systems.
HSPF / HSPF2
Heating Seasonal Performance Factor. A measure of heat pump heating efficiency. Title 24 sets minimum HSPF2 requirements for installed heat pumps.
J
JADU
Junior Accessory Dwelling Unit. A smaller ADU (up to 500 SF) created within an existing primary structure. Title 24 requirements apply.
L
LPD
Lighting Power Density. Measured in watts per square foot, LPD limits set the maximum amount of lighting power allowed in a given area. Title 24 sets LPD limits for all occupancy types.
P
Performance Compliance
A Title 24 compliance path that compares your building's calculated energy use to a code-minimum "standard design" building. Allows design flexibility in exchange for demonstrating overall energy performance.
Prescriptive Compliance
A simplified Title 24 compliance path that requires meeting a specific checklist of minimum requirements (insulation levels, equipment efficiency, etc.) without detailed energy modeling.
Plan Check
The review process by which a building department reviews submitted permit documents (including Title 24 reports) for code compliance before issuing a permit.
S
SEER / SEER2
Seasonal Energy Efficiency Ratio. A measure of air conditioner efficiency over an entire cooling season. Title 24 sets minimum SEER2 requirements for installed equipment.
SHGC
Solar Heat Gain Coefficient. A measure of how much solar heat is transmitted through a window (0 to 1). Title 24 sets maximum SHGC values for windows based on orientation and climate zone.
T
Title 24
Part 6 of the California Code of Regulations — the California Building Energy Efficiency Standards. Sets minimum energy efficiency requirements for all new construction and major renovations.
TI
Tenant Improvement. Construction work performed to customize a commercial space for a new tenant. TI projects often trigger Title 24 compliance requirements for lighting, HVAC, and envelope.
U
U-Factor
A measure of heat transfer (insulation value) for windows and other building components. Lower U-factors indicate better insulating performance. Title 24 sets maximum U-factors for fenestration.
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