Title 24 is the Building Energy Efficiency Standard from the state of California. It is designed for new and existing construction to achieve the desired energy efficiency and preserve the environmental quality. The California Energy Commission is responsible for adopting, implementing and updating the building energy efficiency standards. The Energy Commission is required by the law to adopt standards every three years that are cost effective for homeowners over the 30-year lifespan of the building.
In 2008, state of California put forth ambitious energy-use reduction goals, targeting Zero Net Energy (ZNE) use in all homes by 2020. A Zero Net Energy building means the total amount of energy used by the building on an annual basis is roughly equal to the amount of renewable energy created on site or elsewhere. Title 24 2016 version won't be able to achieve ZNE use in all homes but it'll certainly be close. It is estimated that Title 24 2019 version will take the necessary final steps to achieve ZNE use in residential constructions throughout California.
cove.tool supports Title 24 2016 version with 16 different climate zones spread across California. The measures for energy efficiency according to different climate zones are referenced from Title 24, Part 6 of the California Code of Regulations.
Find out more about Title 24 here: https://www.energy.ca.gov/title24/2016standards/index.html