Is There a Title 24 Calculator?
No online calculator returns a pass or fail for a building. Compliance by calculation is run in software the Energy Commission has approved, and the Commission’s own program, CBECC, is free. It models a whole building from drawings, and its output is only useful once it becomes a signed certificate.
- Choose your report
- Upload your plans
- Pay securely
- Permit-ready report by email
What the free program does
Section 10-109(c)1 describes the Commission’s public domain program: it simulates the energy use of the proposed building and compares it with a standard design energy budget. The standard design has the same location, floor area, volume and configuration, except that wall and window areas are spread equally across the four compass points. Approved third-party programs must follow the same rules; the compliance software page covers approval, and the ACM Reference Manual covers the rules.
What it needs, and what you get
The inputs are a full building description: location, which fixes the climate zone, geometry, assemblies, windows, heating, cooling and water heating. The output is a CF1R. It becomes a compliance document when the documentation author and the responsible person sign it, and, where field verification applies, when it is registered with an ECC-Provider (Section 10-103(a)1). See Title 24 calculations for the modeling and who can prepare a report for the signatures.
The one number you can work out by hand
For a new house, the minimum solar size is kWpv = (CFA × A) / 1000 + (NDU × B), where CFA is conditioned floor area, NDU is the number of dwelling units and A and B come from Table 150.1-C for the climate zone (Section 150.1(c)14). In zone 12, A is 0.613 and B is 1.40, so a 2,000 square foot house works out to 1.226 + 1.40 = 2.626 kWdc before the roof-area limit and exceptions. The system may not be required at all if the result is under 1.8 kWdc; residential solar requirements covers the rest.
Other things called calculators
A heating and cooling load calculation uses ASHRAE, SMACNA or ACCA Manual J methods (Section 150.0(h)1) and is a separate document; see HVAC load calculations. For nonresidential forms, the Commission says NRCC forms can be completed online through Energy Code Ace.
Common Title 24 Questions
- What is Title 24?
- Do I need a Title 24 report?
- How much does a Title 24 report cost?
- How long does a Title 24 report take?
- What is included in a Title 24 report?
- What plans do I need to upload?
Frequently Asked Questions
No. A building department needs the signed certificate of compliance, not a result screen, and registered where field verification applies.
The Energy Commission calls it public domain compliance software, and its software page lists approved versions for single-family, multifamily and nonresidential work.
Explore Energy Calculations
- What Software Is Title 24 Compliance Done In?
- What Is CBECC? The State's Free Title 24 Compliance Software Explained
- Why Do Two Title 24 Consultants Get Different Results for the Same House?
- The Title 24 ACM Reference Manual, Explained
- Does a Title 24 Calculation Require a Site Visit?
View all Energy Calculations guides → · Reports and Calculations · Title 24 guide