What Are Title 24 Energy Calculations for California Buildings?

A Title 24 compliance package for a nonresidential building has two halves: the energy model and the forms. The model simulates the proposed building's annual energy use across envelope, lighting, HVAC, and water heating, then compares it to a baseline building that just meets the prescriptive requirements. Mandatory measures — things like lighting controls, economizers, and commissioning — apply regardless of the compliance path, and the model documents them all. The forms are the NRCC series for nonresidential construction: envelope, mechanical, lighting, and sometimes covered processes, each signed by the designer responsible for that system. These forms travel with the permit application and get reviewed by the plan checker, who can — and does — kick back submittals with math errors or missing signatures. A clean, complete package is one of the quietest ways to keep a California permit on schedule.

Most office projects use the performance path: the model proves the whole building beats the energy budget, which gives the design team trade-off freedom. Want more glass on the lobby? Fine — if the lighting and HVAC are efficient enough to offset it. The prescriptive path skips the modeling but demands every component meet fixed minimums, with no trading. Performance costs more in consultant fees but buys real design flexibility. The choice shapes the project early. Performance modeling rewards integrated design — daylighting paired with dimming controls, high-efficiency HVAC with smart ventilation — while prescriptive compliance is simpler for small, straightforward tenant improvements. An experienced energy consultant will tell you honestly which path fits the project; the wrong choice either wastes modeling fees or boxes the design into prescriptive minimums it didn't need.

The smoothest Title 24 projects treat compliance as a design input, not a submittal task. That means engaging the energy consultant at design development, feeding the model real equipment selections instead of placeholders, and reviewing preliminary results with the MEP engineer before drawings are half done. Each design iteration gets a quick model check, so the compliance margin is known — not guessed — at every milestone. Documentation discipline closes the loop. Equipment schedules must match what the model assumed, control sequences must deliver the mandatory measures the forms claim, and the installing contractor needs the forms that describe what was permitted. When the building department's field inspector shows up, the installed work should match the compliance documents — mismatches are where certificates of occupancy go to wait.

• Engage the energy consultant at design development, not the week before permit submittal
• Feed the model real equipment selections instead of placeholder values that will change
• Review preliminary compliance margins with the MEP engineer at every design milestone
• Match equipment schedules and control sequences to exactly what the model assumed
• Keep the compliance forms with the permit set so field inspectors see consistent documents