Title 24 is a California Energy Commission mandate that adopts and implements energy efficiency standards for both residential and nonresidential buildings. The Standard is meant to impose cost effective (for the life cycle of the building) criteria to set a minimum level of building efficiency. This covers all aspects of building construction, including lighting, appliances, insulation, windows and doors, and controls. The overall purpose of the program is to ensure building construction, system design, and installation to achieve energy efficiency and preserve outdoor and indoor environmental quality. It applies to all new construction and building alterations.
Prescriptive versus Performance Paths
Under Title 24, there are 2 ways to meet the standard requirement.
Performance path: Each building is given a total energy budget where each component of the building contributes to the total budget. As long as the package in its entirety fits beneath the total energy budget, any particular appliance or component maybe utilized. In order to meet the performance path requirements, both a calculation sheet (utilizing approved contribution values) and a field evaluation must be met.
Prescriptive Path: The CEC publishes as part of Title 24 a set of components, when used meet the minimum energy efficiency standards. When operating within this path, deviations and customization are not allowed, in exchange for forgoing engineering calculations and onsite verification.
Water Heater Requirements
All water heater installations must include:
- 120V electrical receptacle that is within 3 feet from the water heater and accessible to the water heater with no obstructions;
- A Category III or IV vent, or a Type B vent with straight pipe between the outside termination and the space where the water heater is installed;
- A condensate drain that is no more than 2 inches higher than the base of the installed water heater, and allows natural draining without pump assistance
- A gas supply line with a capacity of at least 200,000 Btu/hr. In order to meet the prescriptive path, the water heater must either be a single gas or propane instantaneous water heater with an input of 200,000 BTU per hour or less and no storage tank, or a storage tank type water heater with input of less than 75,000 BTU per hour and meets certain insulation requirements for the domestic hot water system. Further, if there is to be recirculation on the home, only Demand Recirculation Systems with manual control pumps shall be used.