What is the difference between MEP Plans and Title 24?

They are two different deliverables that answer two different questions. MEP plans show how the building's systems are physically built, routed, and permitted; the Title 24 report proves the building's design meets the energy-efficiency code. Both go into the same permit package, but they are reviewed by the plan checker as separate documents.

MEP plans: how the systems are built

MEP stands for Mechanical, Electrical, and Plumbing. These are engineered construction drawings — the sheets your contractor builds from and the inspector checks against in the field. They include:

• Mechanical — HVAC equipment, ductwork or mini-split routing, and whole-dwelling ventilation (ASHRAE 62.2).
• Electrical — panel and load calculations, circuit layouts, outlet/lighting locations, and required GFCI/AFCI protection.
• Plumbing — water supply, drain-waste-vent (DWV), and fixture and water-heater locations.

Title 24: proof the design is energy-compliant

The Title 24 report is not a construction drawing — it is a compliance document produced under Part 6 of the energy code, demonstrated through the registered CF1R (Certificate of Compliance). It evaluates the building envelope insulation, HVAC efficiency, water-heating type, high-efficacy LED lighting and controls, and any solar PV requirement, using either the prescriptive path (each component meets a fixed minimum) or the performance path (energy modeling shows the whole building meets or beats a code baseline).

Side-by-side

A concrete example

Picture an 800 SF detached ADU. The Title 24 report runs the energy model and concludes the design complies if it uses a ductless mini-split heat pump at a stated SEER2/HSPF2 efficiency, a heat-pump water heater, and high-efficacy LED lighting with vacancy sensors in the right rooms. Those conclusions are just numbers in a document until the MEP plans turn them into something buildable: the mechanical sheet specifies the exact mini-split make, model, and capacity sized from a Manual J load calculation; the plumbing sheet locates the heat-pump water heater with the air volume and condensate drainage it needs; and the electrical sheet shows the LED fixtures, the required controls, and the circuits feeding all of it. The report says what efficiency is required; the MEP plans say how to install equipment that delivers it.

The two are interdependent: the CF1R sets the minimum HVAC efficiency, water-heater type, and lighting requirements, and the MEP plans must specify equipment that matches those numbers. When the equipment on the plans falls below what the CF1R assumed, the plan checker issues a correction.

That interdependence is exactly why we prepare the Title 24 report as a +$240 add-on alongside your MEP plans — one team keeps the energy report and the construction sheets consistent. The applicable code cycle and local amendments vary — confirm with your local building department. See the Full MEP package, the Title 24 Reports page, or the complete ADU MEP guide.