Lighting rules depend on your code, your code’s edition, your building type, and your project size; not on your building’s age. Title 24, Part 6 and ASHRAE 90.1 both call for auto shutoff, occupancy or vacancy sensors, daylight controls, and dimming in many spaces. Retrofits can trigger these rules too, even with no new construction, which makes commercial lighting control systems one of the most overlooked compliance risks in any building.
Both codes come in more than one edition. A system that passed under an old edition can fail under a new one. This guide sorts every rule by its code and edition. If you’d rather hand the job to a licensed team, Vision Line designs, installs, and tests code-compliant LED lighting controls, and handles rebate paperwork too, including projects that need lighting controls in NJ compliance.
What Is the Difference Between Title 24 and ASHRAE 90.1?
Title 24, Part 6 is California’s own energy code. ASHRAE 90.1 is the national standard used by most other states, either directly or through the International Energy Conservation Code (IECC). Both limit lighting power and require controls, but they are separate documents on separate schedules.
Title 24, Part 6 only applies in California and updates every three years; the current edition is Title 24, Part 6 (2022), in effect since January 2023. ASHRAE 90.1 is used by most other states, and since states adopt new editions at different times, both ASHRAE 90.1-2019 and ASHRAE 90.1-2022 are still in use. New Jersey uses ASHRAE 90.1-2019, in effect since September 2022; not the 2022 edition, and not Title 24.
Which Code Applies to Your Building?
California buildings follow Title 24, Part 6. Every other state follows the ASHRAE 90.1 edition it has adopted. Building type matters too: offices, classrooms, and conference rooms face the strictest rules; open-plan offices now need sensors under Title 24 (2022) and ASHRAE 90.1-2022 (older editions often skipped this); and warehouses, garages, and retail spaces follow their own separate rules. Always check the exact code edition on your permit, since states often adopt a new edition years after it is published.
Do Small Retrofits Trigger the Rules Too?
Yes. Both codes apply control rules to many retrofits, not just new buildings. Under ASHRAE 90.1-2019, Section 9.4.1, changing more than 20% of a space’s lighting load triggers full compliance, including new sensors, even for a simple fixture swap. Title 24 uses a similar rule tied to circuit or fixture changes.
A plain LED swap on the same wiring often does not require new sensors, but crossing that 20% threshold pulls the whole space into full compliance. Always check the exact number with your local building office first.
What Lighting Controls Are Required, and Under Which Code?
All three editions require occupancy or vacancy sensors, auto shutoff, daylight dimming, and multi-level dimming; but exact space sizes differ by edition.
Occupancy Sensor Rules
Newer codes now cover open offices that older codes skipped. Rules for occupancy sensors in commercial lighting projects must follow have expanded with each new edition. Title 24 (2022) requires sensors in all offices, each covering up to 600 sq. ft. ASHRAE 90.1-2022 requires sensors in small enclosed offices and open offices 300 sq. ft. or larger, with the same cap. ASHRAE 90.1-2019 has no single 600 sq. ft. cap; limits vary by space type.
An occupancy sensor turns lights on and off by itself; a vacancy sensor needs a manual “on” but shuts off on its own. Both meet the shutoff rule, though some rebates favor vacancy sensors since manual-on wastes less power.
Daylight Harvesting Rules
Daylight harvesting controls are required in set zones, not near every window. A sensor dims or switches lights based on daylight in one isolated zone. Title 24 (2022) requires this in qualifying zones with a calibrated sensor wired apart from other circuits. ASHRAE 90.1-2022 and 90.1-2019 both require daylight controls in set zones under Section 9.4.1, each with its own zone formula.
Dimming Rules
Multi-level dimming gives one step between full-on and full-off. Continuous dimming allows full-range control. Title 24 (2022) and ASHRAE 90.1-2022 both require dimming in classrooms, conference rooms, and open offices; ASHRAE 90.1-2019 requires similar dimming, but its space list differs.
Exact Numbers by Code Edition
The exact numbers differ by code and edition; mixing them up is the most common mistake.
|
Rule |
Title 24 (2022) |
ASHRAE 90.1-2022 |
ASHRAE 90.1-2019 |
|
Sensors |
All offices, any size |
Small enclosed + open 300 sq. ft.+ |
No universal open-office rule |
|
Shutoff time |
20 minutes |
20 minutes |
20 minutes |
|
Max zone/sensor |
600 sq. ft. |
600 sq. ft. |
Varies by space type |
|
Power cut on vacancy |
At least 80% |
Up to full-off |
At least 50% in some spaces |
|
Daylight controls |
Required |
Required (Sec. 9.4.1) |
Required, different formula |
|
Demand response |
4,000W or more |
No base rule |
No base rule |
|
Retrofit trigger |
Circuit/fixture scope |
Section 9.4.1 |
Over 20% of load |
Two numbers cause the most failed inspections: the 20-minute shutoff rule, which applies to all three editions, and the 600 sq. ft. zone cap, which applies only under Title 24 (2022) and ASHRAE 90.1-2022; not under ASHRAE 90.1-2019.
Title 24 (2022) also requires demand response at 4,000W or more; ASHRAE 90.1 has no such rule. Controlled outlets are separate: at least 50% of outlets in offices must sit on a timer, schedule, or occupancy control under both codes.
Common Retrofit Mistakes That Fail Inspection
The top cause of failure is reusing an old sensor layout without checking the current code. This is why commercial lighting control systems installed even a few years ago often need a fresh review. Common issues include oversized zones, missing daylight isolation, wrong shutoff timing (30 minutes or longer), and missing test records; skipping required acceptance testing is a failure on its own.
What Happens If You’re Not Compliant?
Non-compliance can block your certificate of occupancy, cost you rebates, and create risk during a sale. A failed inspection can delay move-in for weeks. Fixing issues after walls close costs far more than catching them early. Rebate programs often require full compliance, not just working fixtures, and buyers now check lighting compliance during due diligence.
Who Can Help You Get It Right the First Time?
A licensed electrician who knows both the code and the rebate process can prevent most of these problems. Vision Line is a fully licensed commercial electrician working across multiple states, with experience designing, installing, and testing LED lighting controls for buildings of 20,000 sq. ft. and up, including occupancy sensors, so commercial lighting spaces need to pass inspection on the first try. Our designs are built around the code edition that governs your building, our team handles rebate paperwork with a strong approval record, and our own inventory and delivery fleet mean installation can often start within two weeks of approval. Many projects also qualify for interest-free financing through local utility loan programs.
If your building needs a retrofit, a rebate-funded upgrade, or a pre-sale check, we offer a free consultation.
How to Self-Audit Before an Inspection or Sale
Check four things: sensor zone size, shutoff time, daylight isolation, and test records. Confirm your exact code and edition, measure each sensor zone against its limit, time the shutoff to confirm it happens within 20 minutes, and pull your test records.
What Code Applies in New Jersey?
New Jersey follows ASHRAE 90.1-2019, in effect since September 2022, under N.J.A.C. 5:23-3.18; not the 2022 edition, and not Title 24. Zone size has no fixed 600 sq. ft. cap; limits follow the 2019 edition’s space rules. Renovations fall under New Jersey’s Rehabilitation Subcode (N.J.A.C. 5:23-6), which sets its own rules based on scope. Anyone managing lighting controls in NJ compliance should confirm these details before finalizing a design.
Vision Line is based in Bridgewater, New Jersey, and works with ASHRAE 90.1-2019 daily; a strong fit for a lighting controls in NJ project that needs a compliant design and a smooth rebate process.
Key Takeaways
Compliance always depends on your exact code, edition, building type, and project scope; not one universal number.
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Confirm your code and edition first. Title 24 only applies in California; most other states follow a specific ASHRAE 90.1 edition, not the newest one.
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Retrofits can trigger full compliance, especially past the 20% load threshold under ASHRAE 90.1-2019.
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The 600 sq. ft. zone cap only applies under Title 24 (2022) and ASHRAE 90.1-2022.
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The 20-minute shutoff rule is the same across all three editions, and daylight harvesting controls need isolated wiring, not just a sensor on the wall.
Ready to upgrade with confidence? Vision Line handles the design, installation, testing, and rebate paperwork for commercial LED lighting, so your system meets the code that applies to your building from day one. Reach out today for a free lighting consultation.
This blog covers general rules under Title 24, Part 6 (2022), ASHRAE 90.1-2022, and ASHRAE 90.1-2019. Codes update every three years and often carry local amendments. Confirm current rules with your local building office or a licensed electrical engineer first.
FAQs
Do LED retrofits always need new occupancy sensors?
Not always. A plain swap on the same wiring may not trigger new sensors, but crossing 20% of the connected load under ASHRAE 90.1-2019 usually does.
What’s the difference between an occupancy and a vacancy sensor?
An occupancy sensor turns lights on and off by itself. A vacancy sensor needs a manual “on” but still shuts off on its own.
Can one sensor cover a whole open office?
No, not under Title 24 (2022) or ASHRAE 90.1-2022. Each sensor is capped at 600 sq. ft.
