Case studies — real CA projects, real compliance paths

What each case study will cover

Title 24 compliance is one of those domains where the abstract rules don't tell you much about a real project. The same prescriptive table line lands differently depending on the lot, the existing residence (or lack of one), the climate zone's cooling vs heating bias, and what equipment is already on the roof or in the garage. Case studies are how we share what we actually do — not the marketing pitch, the working detail.

Each published case study follows the same structure so they're easy to skim and compare:

1. Project at a glance. Climate zone, city/county, scope category (Newly Constructed, Addition + Alteration, Alteration Only, Detached ADU, Attached ADU, non-ADU addition), conditioned floor area, story count, bedroom count.
2. The starting conditions. What the plans showed, what the existing residence's equipment lineup was (for Add+Alt), and any constraints the design team had locked in before compliance got involved (a specific roof material, a particular window vendor, an HVAC contractor's preferred brand).
3. The prescriptive baseline. What Title 24 Part 6 Table 150.1-A asks for in the project's climate zone — wall and ceiling R-values, window U-factor and SHGC, HVAC HSPF2/SEER2/EER2 tiers, DHW heater type, required PV size if applicable. Pulled from the same per-CZ data that drives the design-options generator.
4. The scope challenge. What about this specific project made the prescriptive path inconvenient, expensive, or impossible. Common patterns: a 2x4 framing convention the builder wouldn't move off of, an existing gas furnace the client wanted to keep on an Add+Alt, a CZ12 cooling tightening that made the default cooling tier under-sized, a small addition that triggered the §150.1(c)14 Exception 2 PV waiver.
5. The design path chosen. Which of the three design options (Prescriptive / 2x4 Performance / 2x6 Enhanced) the project picked and why. We explain the trade-off — usually some mix of up-front cost, contractor familiarity, equipment availability, and compliance headroom.
6. What we did differently. The judgment calls that don't show up on the Title 24 report (CF1R). A QII waiver because the addition was under 700 sf. A roof-material translation from asphalt to tile that preserved compliance. A heating-preference override that let the client keep an existing gas furnace on an Add+Alt run. Use of the ZIP-derived climate zone over what the architect's title block claimed.
7. The outcome. The final compliance margin (LSC efficiency, PeakCool, PeakHeat), the registered CF1R, and any post-registration steps (field verification scheduled, CHEERS signature timing, any plan-check feedback from the AHJ).
8. Lessons. What we'd do differently next time on a similar project, or what the reader should watch out for if they're staring at the same trade-off.

Why we publish case studies

The honest reason: the compliance industry runs on rumor. Designers learn what works from their last project. Builders pass advice across job sites. The actual prescriptive tables are available, but the working knowledge of which combinations actually pass in which climate zones tends to be tribal — held inside firms, traded over coffee, never written down. We'd rather write it down.

Every project we run produces some small piece of working knowledge that wouldn't be obvious from reading the code. The 2x4 wall in CZ10 needing extra cooling headroom because the lighter wall conducts more heat. CZ12's combined SHGC + HVAC bump that lets the prescriptive path clear PeakCool without exotic equipment. The §150.2(a) Exception 1 cool-roof waiver for additions under 300 sf. We surface those in articles where it makes sense; for the long tail, case studies are a better fit.

How to be featured as a case study

We publish case studies only with explicit client consent and with all identifying detail anonymized — street name plus city, never house number; never the owner's name; never the AHJ correspondence reference number. If you're starting a project on this site and want to be considered for the case-study series, mention it when you upload the plans. We'll reach out after the compliance package is closed.

Projects we're particularly interested in documenting:

• Anything in CZ12 or CZ16 — the two zones where the prescriptive path runs tightest.
• Add+Alt projects where the client kept an existing gas furnace or gas water heater.
• Detached ADUs under 700 sf — small projects with tight PV-mandate math.
• Multi-story projects (the wall-area calculation has a couple of failure modes worth documenting).
• Cool-roof climate zones where the radiant-barrier interaction came up.
• Any project where the AHJ asked a substantive question on the report we registered.

While the series gets going

Case studies are still in the publishing queue. In the meantime, the reference articles cover the structural questions case studies will illustrate:

• California's 16 climate zones — what changes by zone.
• Addition vs Alteration vs Add-Alone — which scope applies when.
• HVAC sizing for CA residential — Manual J, prescriptive tiers, and equipment selection.
• Heat pump water heater selection — NEEA tiers and per-CZ requirements.
• §150.1(c)14 PV mandate decoded — when PV is required and how it's sized.

More case studies coming as we publish them.