Title 24 Compliance Methods
Prescriptive Compliance Approach: The prescriptive approach is the simplest way to comply with the building envelope requirements but generally offers limited flexibility; however, the 2016 revisions have added increased flexibility for prescriptive compliance. If every prescriptive requirement is met, the building envelope complies with the Energy Standards. The prescriptive envelope requirements are prescribed in §150.1, which includes Table 150.1-A. The prescriptive compliance approach consists of meeting specific requirements for each envelope component, plus meeting all minimum mandatory requirements, such as mandatory levels of insulation.
 
Prescriptive requirements apply to:
1. Fenestration.
2. Roofs and ceilings, including exterior roofing products.
3. Exterior walls.
4. Floors. 
 
Performance Compliance Approach: The prescribed mandatory measures and prescriptive requirements affect the design and operation of the building. Mandatory measures, prescriptive requirements, and operational schedules establish a minimum performance level that can be exceeded by other design measures and construction practices, resulting in greater energy savings. The performance approach is a more sophisticated compliance method, and it offers greater design flexibility than the prescriptive approach. The performance approach may be used for any unique design element(s) that the user of a compliance modeling software believes could contribute to the overall energy use of the building. The performance approach allows for more energy tradeoffs between building features, such as increasing HVAC equipment efficiency to allow more fenestration area.