HVAC systems represent the largest source of energy use in most California buildings, which is why Title 24's mechanical requirements are extensive and technically demanding. This guide covers the key HVAC compliance concepts every Los Angeles contractor, architect, and building owner should understand.
Equipment Efficiency Requirements
Title 24 sets minimum efficiency ratings for all HVAC equipment installed in new and renovated California buildings.
Cooling Equipment
Central air conditioners: Minimum SEER2 (Seasonal Energy Efficiency Ratio) requirements vary by capacity
Mini-split and multi-split systems: Minimum EER2 requirements
Packaged units: Minimum IEER requirements for commercial applications
Heating Equipment
Gas furnaces: Minimum AFUE (Annual Fuel Utilization Efficiency) of 80% for non-weatherized, higher for some applications
Heat pumps: Minimum HSPF2 (Heating Seasonal Performance Factor)
Electric resistance: Subject to specific use restrictions under the 2022 standards
Heat Pump Water Heaters
Under the 2022 standards, heat pump water heaters (HPWHs) are required or strongly incentivized in most new low-rise residential buildings. HPWHs must meet minimum Uniform Energy Factor (UEF) requirements.
Duct System Requirements
Duct systems are a major source of energy waste in California's residential buildings, which is why Title 24 has strict requirements for duct insulation and sealing.
Duct Insulation
Ducts in unconditioned spaces (attics, crawlspaces) must be insulated to R-6 minimum
Higher R-values required in some climate zones
Duct Sealing and Leakage Testing
All supply and return ducts must be sealed with approved mastic or metal tape
In most cases, HERS raters must verify duct sealing via pressure testing
Maximum allowable duct leakage: typically 6% or 15% depending on the compliance path
Thermostat and Control Requirements
Title 24 requires programmable or smart thermostats in most residential applications and sophisticated BAS (Building Automation Systems) controls in commercial buildings.
Residential Requirements
Programmable thermostat with heating and cooling setback capabilities
Manual or automatic setback during unoccupied periods
Heat pump thermostats: Must be "intelligent" with optimized defrost and emergency heat controls
Commercial Requirements
Zone-level controls with setback and setup capabilities
Demand-controlled ventilation (DCV) using CO2 sensors in high-occupancy spaces
BAS integration for buildings over 10,000 SF
Ventilation Requirements
Title 24 incorporates ASHRAE Standard 62.2 (residential) and 62.1 (commercial) ventilation requirements to ensure adequate indoor air quality.
Residential Ventilation
Whole-building mechanical ventilation required in most new homes
Kitchen and bathroom exhaust fans must meet minimum airflow and sound requirements
Heat recovery ventilators (HRVs) or energy recovery ventilators (ERVs) incentivized in some climate zones
HERS Verification Requirements
Many HVAC compliance measures require field verification by a HERS (Home Energy Rating System) rater before the Certificate of Occupancy is issued. Common HERS-verified measures include:
Duct leakage testing
Refrigerant charge verification (for split systems)
Airflow measurement
Installed HVAC equipment efficiency verification
Working with Title24.IO on HVAC Compliance
Our mechanical compliance analysis ensures your HVAC system design meets Title 24 requirements before you submit for permit. We:
1.**Review equipment specifications** against current efficiency requirements
2.**Model duct systems** and flag potential compliance issues
3.**Identify HERS verification requirements** and connect you with trusted raters
4.**Prepare complete mechanical documentation** for your permit package
Contact us today for a consultation on your Los Angeles HVAC compliance project.