Title 24 Cool Roof Initiative


California has statewide Title 24 energy standards.

Many Californians have wondered “what is Title 24?” and “why do I need a Title 24 energy report for my project?” Throughout California the Title 24 energy standards address the energy efficiency of new (and altered) homes and commercial buildings. Because energy efficiency reduces energy costs, increases reliability and availability of electricity, improves building occupant comfort, and reduces impacts to the environment, standards are important and necessary for California’s energy future. In 1978 the California legislature enacted the Title 24 energy standards. The standards are contained within Title 24, part 6 of the California Code of Regulations.


The goal of the California Title 24 energy standards is the reduction of energy use. This is a benefit to all. Homeowners save money, Californians have a more secure and healthy economy, the environment is less negatively impacted, and our electrical system can operate in a more stable state. The 2008 Title 24 standards (for residential and nonresidential buildings) are expected to reduce the growth in electricity use by 561 gigawatt-hours per year (GWh/yr.) and reduce the growth in gas use by 19 million therms per year (therms/yr.). The savings attributable to new low-rise residences are 102.2 GWh/yr. of electricity savings and 7.4 million therms. These savings are cumulative resulting in 6 times the annual saving over the 3 years to the next Title 24 standard cycle.


Buildings are one of the major contributors to electricity demand. We learned during the 2000/2001 California energy crisis, and the east coast blackout in the summer of 2003, that our electric distribution network is fragile and system overloads caused by excessive demand from buildings can create unstable conditions. Furthermore, resulting blackouts can seriously disrupt business and cost the economy billions of dollars. Since the California electricity crisis, the Energy Commission has placed more and more emphasis on demand reductions. The 2008 Title 24 standards are expected to reduce electric demand by 131.8 MW each year and 36.6 MW are attributable to low-rise residential buildings. Like energy savings, demand savings accumulate each year. Changes to the Title 24 standards occur periodically to account for improvements in conservation technologies, changes in the cost of fuels and energy-conserving strategies, and improved capabilities in analyzing building energy performance. In addition, modifications are also made to further improve compliance and enforcement of the Title 24 standards.

(Excerpted from the CEC Title 24 Residential Compliance Manual)


As houses have been tightened up over the last twenty years due to energy cost concerns and the use of large sheet goods and housewrap, what used to be normal infiltration and exfiltration has been significantly reduced. In the meantime, we have introduced thousands of chemicals into our houses through building materials, cleaners, finishes, packaging, furniture, carpets, clothing and other products.

The California Title 24 energy standards have always assumed adequate indoor air quality would be provided by a combination of infiltration and natural ventilation and that home occupants would open windows as necessary to make up any shortfall in infiltration. However, Commission sponsored research on houses built under the 2001 Title 24 standards has revealed lower than expected overall ventilation rates, higher than expected indoor concentration of chemicals such as formaldehyde and many occupants who do not open windows regularly for ventilation.

Starting on January 1st, 2010 all new homes (and existing homes with additions over 1000 sq. ft.) were required to be equipped with mechanical whole house ventilation. The ventilation rate (cfm) depends on the size of the house and number of bedrooms.

There are three generic solutions to meeting the Title 24 continuous outside air ventilation requirement:

  • Exhaust ventilation
  • Supply ventilation
  • Combination of supply and exhaust ventilation

Use the chart below to quickly calculate the required continuous ventilation CFM for your residential project:

Title 24 Continuous Ventilation Rate (in CFM)

More information on Title 24 continuous ventilation requirements including exhaust ventilationsupply ventilationcombination ventilationintermittent ventilation, and control and operation of continuous ventilation systems

View or download the Indoor Ventilation Minimum Best Practices Guide based on ASHRAE 62.2

(Excerpted from the CEC Title 24 Residential Compliance Manual)


Energy use depends partly on climate conditions which differ throughout the state. To standardize Title 24 calculations and to provide a basis for presenting the criteria, the California Energy Commission has established 16 climate zones which are used with both the low-rise residential and the non-residential Title 24 energy standards. Cities may occasionally straddle two climate zones. In such cases, the exact building location and correct climate zone should be verified before any energy calculations are performed. If a single building development is split by a climate zone boundary line, it must be designed to the requirements of the climate zone in which 50% or more of the dwelling units are contained.

California Climate Zones 1-16

(Excerpted from the CEC Title 24 Residential Compliance Manual)