Title 24 Energy Calculation:
Understanding California’s Energy Code
Effective for permits filed on or after January 1, 2026, changes to Title 24 requirements will have a major impact on California builders and developers; especially in the realms of solar (PV), battery storage (BESS) readiness, and electric-system preparation.
Among the most significant updates are tighter electric-readiness requirements, stronger ventilation mandates, and updated rules for solar sizing using the Solar Access Roof Area (SARA) method with roof-slope multipliers. We’ve compiled this data to help you set and record your Title 24 energy calculations to ensure full compliance.
What “Energy Calculation” Means on the Prescriptive Path
When a project uses the prescriptive path under Title 24, the goal isn’t trade-off modelling (that’s the performance path) instead you’re aim is to verify the meeting of each required measure. That means each prescriptive item must be satisfied.
Here are a couple of the major calculation-type items:
- PV capacity (for new construction): Under the 2025 code changes, sizing methods are based on SARA (Solar Access Roof Area) times a given watt-per-square-foot (W/ft²) multiplier. This typically works out to 18 W/ft² for steep-sloped roofs and 14 W/ft² for low-slope roofs.
- Battery-ready / electric-readiness: Buildings with larger service sizes (for example, single-family new builds with main service over 125 A), require pro-active planning for BESS readiness to include space, conduit, labeling, and panel capacity.
Note: if a BESS is already installed, this requirement may not apply.
For integrators, electricians, IT professionals, and mechanical engineers, understanding these calculations is critical.
Single-Family (New Build) Prescriptive Energy Checklist
Goal:
• Size PV coverage via SARA methodology
• Plan for battery-readiness / electric readiness
• Document and submit properly for code compliance
Step-by-Step:
1. Calculate SARA & PV Size
First, identify steep-slope vs low-slope roof area (SARA). For steep-slope roofs, calculate: SARA × 18 W/ft². For low-slope roofs, calculate: SARA × 14 W/ft². Apply the appropriate equation based on the roof type, and if another code equation also applies, use the smaller of the two required sizes.
Example: For a steep slope of 320 ft² → 320 × 18 = 5,760 Wdc. For a low slope of 100 ft² → 100 × 14 = 1,400 Wdc. Total ~7,160 Wdc (7.16 kWdc).
2. Plan Battery-Ready Install (if service over 125 A)
3. Lay Out Monitoring & Load-Management Points
4. Install and Verify
How Loxone Helps in Residential Spaces
- Miniserver / Miniserver Compact: The Loxone central control unit. Used to schedule, log, and automate scenes.
- Energy Meter / Modbus Extension: Monitor inverter output and HPWH/EVSE data where devices support Modbus.
- Relay Extension / Smart Socket Air US: Stage large loads (HPWH, EVSE, dryer) during peak times or in instances of PV surplus.
- Weather Station (optional): Automate exterior loads, lighting, and shading with solar and daylighting data.
Nonresidential (New Build) Prescriptive Energy Checklist
Goal
• Apply PV sizing and electric‐readiness using SARA method (and/or any other applicable equation under §140.10)
• Plan acceptance where building automation & energy controls intersect with lighting & DR (demand response)/daylighting
Step-by-Step:
1. Size PV Using SARA
2. Plan for Battery-ready / Electric-ready
3. Acceptance Planning
4. Use Automation for Load Control
Automated Load-Management Examples:
Here are some real-world load management strategies you can implement with Loxone.
- Heat Pump Water Heater (HPWH): Pause during early peak, resume when PV generation is above threshold.
- EVSE: Delay start until late night or when PV surplus is available.
- Pool Pump: Run midday to align with PV output; pause during a demand response event.
- Clothes Dryer: Prevent operation simultaneously with EVSE to avoid main panel tripping.
What to Log for Your Close-Out Packet
Here’s what you’ll need to capture after system start-up (aim for 1–2 representative weeks of operation):
✅ Timestamp (date/time, local)
✅ PV power (kW) or energy (kWh) from inverter/meter
✅ Grid import/export (kW or kWh) if available
✅ Large loads status/power: HPWH, EVSE, HVAC aux heat, pool/spa (select based on project)
✅ Any demand response events received & scenes applied
Notes: setpoint changes, outage/maintenance markers
Export logs from your automation system (e.g., Miniserver trend logs) → CSV + one-page graph → include in record set.
Required Paperwork
| Building Type | Design → Installation → Verification Forms |
| Residential | CF1R-PV or CF1R-PRF → CF2R-ELC/PV → CF3R |
| Nonresidential | NRCC-ELC/PV → NRCI-ELC/PV → NRCA-LTI (if lighting/DR controls) |
These form sequences correspond to the 2025 code compliance sequence.
Why Title 24 Matters to Your Business
As an integrator, electrician, IT-pro or mechanical engineer working in California’s growing smart home/automation market, these code changes represent unprecedented business opportunity. How so?
The market is shifting and old equipment and automation systems are no longer enough. And with Title 24’s new prescriptive mandates (solar sizing, storage readiness, electric-readiness) home and business owners need your services are needed more than ever. By mastering these energy calculations and the integration of automation/monitoring systems (like Loxone), you can diversify your business, stand out from competition, and capture higher value projects.
Being fluent in code compliance and offering full stack Title 24 solutions (PV, BESS readiness, automation and load management) positions you as the professional who solves compliance, delivers efficiency, and reduces risk for your clients.
Final Thoughts
By understanding how the prescriptive path to compliance works (and what “energy calculations” mean), and by leveraging automation/energy-control tools (such as Loxone) for monitoring and intelligent load-management, you position your business ahead of the curve.
Be prepared, document thoroughly, and deliver smart- compliant solutions. Your clients, your business and the California grid will all benefit.
Compliance Made Simple. Comfort Made Smarter.
In 2026, Title 24 compliance won’t just be a box to check, it defines how California builds. With Loxone, you’ll meet the standard today and be ready for what’s next.
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Igor Beletsky
