What a Title 24 correction letter actually is
When you submit a permit set to your local building department (the AHJ — Authority Having Jurisdiction), a plan-checker reviews it for code compliance. If something on your CF1R or the supporting drawings doesn't match, contradicts itself, or fails to demonstrate compliance, the reviewer issues a correction letter (also called a "comment letter" or "plan-check comments") — a numbered list of items that must be resolved before the permit can issue.
Title 24 corrections are usually a single section of a longer letter that also covers structural, mechanical, plumbing, and accessibility comments. The Title 24 items typically reference §150.0, §150.1, §150.2, or specific Joint Appendix (JA) numbers — JA4 quality insulation, JA8 high-efficacy lighting, or JA13 air-leakage testing.
Common Title 24 plan-check citations
Most Title 24 corrections fall into a handful of categories — the same handful, across most California AHJs:
- CF1R doesn't match the architectural set
- Window U-factor or SHGC on the CF1R differs from the window schedule on the drawings. Floor area on the CF1R doesn't match the calculated CFA on the cover sheet. Wall construction listed on the CF1R doesn't match the wall section.
- Wrong climate zone or wrong scope
- The CF1R was run for a CZ that doesn't match the project ZIP, or the project was modeled as Newly Constructed when it's actually an Addition + Alteration.
- HVAC or DHW equipment not certified
- Specified model isn't on the AHRI directory; HPWH isn't on the NEEA Tier list; window product isn't NFRC-certified.
- Missing PV sizing
- Newly-constructed dwellings under §150.1(c)14 must show required PV sizing on the CF1R; additions and alterations are exempt and shouldn't show one.
- Missing CHEERS registration
- The submitted CF1R is a draft, not a registered version with a CHEERS ID. AHJs increasingly reject unregistered CF1Rs at intake.
- Quality Insulation Installation (QII) inconsistency
- The CF1R is claiming credit for QII but the drawings don't call out the inspection requirement, or vice versa.
- Demand-control ventilation / IAQ fan
- Mechanical ventilation rate on the CF1R doesn't match the fan schedule, or the IAQ fan isn't sized to ASHRAE 62.2.
How to respond cleanly the first time
Plan-checkers are reading dozens of letters a week. A response they can verify in two minutes will issue; one that takes ten minutes will get kicked back. Most Title 24 comments aren't CF1R errors — they're places where a window schedule, wall section, or equipment callout on the architectural set drifted from what the CF1R was registered with. The pattern that works:
- State which sheet you updated and where to look. "Comment 7 — Window schedule on A-501 corrected from U-0.32 to U-0.30 to match the registered CF1R. See revised A-501, line 14."
- Fix the drawing that contradicts the CF1R, not the other way around. When the CF1R already carries the correct U-factor / SHGC / wall assembly / equipment model, the architectural sheet is what needs to move. If the wall section on A-301 disagrees with the CF1R, fix A-301 and resubmit both — don't make the CF1R chase a stale drawing.
- Re-issue the CF1R only when the registered values themselves were wrong. If the wall assembly, equipment, or scope on the CF1R was genuinely incorrect, a revised CF1R registered with CHEERS supersedes the previous version cleanly. AHJs do not accept handwritten corrections on a printed CF1R.
Our plan-check response flow
If your project went through this site, the project dashboard has a built-in plan-check intake. Upload the AHJ correction letter as a PDF (or paste the text directly), and an analyzer reads through the comments and separates the Title 24 items from the structural / accessibility / etc. items. For each Title 24 item, you get an analysis that classifies the fix into one of two paths:
- Title 24 fix — a revised CF1R with the corrected values can resolve the comment without re-running the design. We re-issue and re-register through CHEERS, and the dashboard hands you the revised PDF.
- Restart required — the comment changes a fundamental input (scope, climate zone, conditioned area, equipment type) badly enough that the prior compliance run is no longer valid. The right answer is a fresh project. The dashboard surfaces this clearly so you don't pay to re-issue something that won't pass.
The plan-check intake is included for projects that bought the original compliance package; the analysis is no extra charge. Multiple correction rounds on the same project are supported.
When restarting beats patching
Some corrections are technically possible to resolve with a CF1R revision but practically wrong to. Common cases where a fresh project is the right call:
- The plan-checker flagged the project as the wrong scope (e.g. modeled as new construction when it's actually addition + alteration). Scope changes the prescriptive baseline AND the PV requirement; everything downstream changes too.
- The conditioned floor area on the drawings is materially different from what the CF1R was sized off. Insulation, glazing, and HVAC sizing all key off CFA.
- The climate zone resolved wrong because the project address had an unusual ZIP. Every prescriptive value changes by zone.
- The selected design path no longer pencils after a major architectural change — different envelope, different fenestration percentage, different bedroom count.
References
The CEC publishes a 2025 Compliance Manual that's the canonical source for what each prescriptive section requires. For ZIP-to-climate-zone resolution (the single most common citation), the free ZIP→CZ lookup tool will tell you the correct zone in one keystroke. For the prescriptive table values that drive most of the citations above, see the California climate zones overview and the per-zone landing pages it links to.