CLC Cheat Sheet 2026

The 30 highest-yield CLC facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. What is 'glare' in commercial lighting, and why is it a concern in office environments? → Excessive brightness or contrast that causes discomfort and reduces visibility
2. A retail store wants to highlight merchandise with high contrast. Which technique is most appropriate? → Accent lighting with a 3:1 to 5:1 accent-to-ambient ratio
3. What is the primary advantage of a networked lighting control system over a standalone relay-based system in a large commercial building? → Centralized monitoring, scheduling, and energy reporting across all zones
4. What does an Daylight Autonomy (DA) value of 65% indicate for a given sensor point? → The target illuminance is met by daylight alone for 65% of annual occupied hours
5. Which document establishes the intended performance expectations of a lighting system before commissioning begins? → Owner's Project Requirements (OPR)
6. The FTC 'Green Guides' are relevant to a lighting consultant specifying products because they govern: → Truthfulness of environmental marketing claims such as 'energy-saving' and 'eco-friendly'
7. What is 'maintained illuminance' as used in commercial lighting design? → The average illuminance at the end of the maintenance cycle, accounting for depreciation
8. What is the relationship between daylighting integration and overall Certified Lighting Consultant professional competency? → It is an essential component that strengthens the overall competency framework
9. When DIALux EVO imports an IES file and renders a 3D visualization, what does the 'luminous flux' value in the file represent? → The total light output of the lamp inside the fixture in lumens
10. When commissioning a daylight harvesting closed-loop system, where should the photosensor be aimed to measure the correct work-plane illuminance? → Downward toward the work plane, away from direct view of windows
11. How does smart lighting improve user experience? → Offers automation and personalization
12. How should CLC professionals measure success in light source technology & leds? → Using defined metrics, benchmarks, and regular evaluation against established goals
13. A luminaire has a listed price of $480 and the project receives a 35% contractor discount. What is the net unit cost? → $312.00
14. A commercial office space has an average maintained illuminance of 300 lux. According to IESNA recommendations, is this adequate for general office work? → No, general office work requires at least 500 lux
15. Which term describes the ratio of maintained horizontal illuminance to minimum horizontal illuminance across a defined area? → Illuminance uniformity ratio
16. The R9 value within the extended CRI test is specifically used to evaluate a source's ability to render which color? → Saturated red
17. What is the role of color temperature in lighting design? → It affects the ambiance and perception of a space
18. An office measures 250 melanopic EDI at the eye. According to WELL v2 L07 Feature, is this sufficient for daytime circadian support? → No, WELL v2 requires at least 275 melanopic EDI for 4+ hours
19. When implementing daylighting integration practices, what should CLC professionals prioritize? → Alignment with professional standards, stakeholder needs, and organizational goals
20. How should CLC professionals measure success in daylighting integration? → Using defined metrics, benchmarks, and regular evaluation against established goals
21. What does the term 'binning' refer to in LED manufacturing? → Sorting LEDs by flux, color, and voltage into consistent groups
22. Which certification indicates a lighting product is energy efficient? → ENERGY STAR®
23. A project's lighting budget is $120,000. If fixture costs represent 60% and controls represent 15%, how much remains for labor and miscellaneous? → $30,000
24. What is the maximum uniformity ratio (maximum to minimum illuminance) permitted along an egress path under NFPA 101? → 40:1
25. A utility's 'demand charge' penalizes buildings based on which electrical characteristic? → Peak kilowatt draw during billing period
26. What is a common pitfall when implementing emergency & exit lighting standards practices? → Failing to adapt approaches to specific contexts while maintaining core principles
27. What effect does increasing drive current beyond an LED's rated level have on efficacy? → Efficacy decreases due to thermal droop and resistive losses
28. Which metric introduced by IES TM-30 provides a measure of the hue shift caused by a light source across 16 color categories? → Rcs,h1 (Hue Angle Shift)
29. What is the importance of energy codes in lighting? → They regulate energy use and efficiency
30. Dynamic glazing (electrochromic glass) in a daylighting system primarily benefits occupants by: → Allowing real-time adjustment of tint to control glare and solar heat gain