Title 24 Documentation
This is the process of designing homes which meet the California building energy efficiency standards. It covers all types of things like replacing windows, swapping out an HVAC system, additions/alterations to existing homes, and new home design. There are two primary ways of showing that your project meets code -prescriptive or performance based.
The prescriptive approach is the standard of building design that is used throughout California. It varies based on what climate zone the project is located in. When using this method of compliance the builder or installer is required to meet the efficiency requirements for that climate zone. This can apply to things like furnace changeouts, replacing a few windows, or even building an entirely new home. When this method is used for a whole home each aspect of the design must exactly match the prescriptive requirements which means that there is no flexibility allowed in the design. Using the prescriptive approach can be very useful for things like smaller alterations as they speed the process up and don't require as much documentation as the performance approach.
The performance approach is the method commonly used when the designer or architect wants more control over how the home is built. When using the performance approach designers can pick and choose the energy efficiency upgrades that they want installed in the home. If they choose to install a high efficiency water heater they may be able to reduce the amount of insulation in the walls. It's a balancing act. As long os the home meets or exceeds the standard compliance margin the home gets the green light. If however it falls short of the requirements then other measures will need to be added into the design to get it into compliance. This approach takes longer to model but is often the prefered method when it comes to optimised design and value engineering.