Light Meters for Illuminance: Rent or Buy

Footcandles are used in the US; lux is the international (SI) unit. 1 footcandle = 10.76 lux. Which you use depends on your applicable standard or client requirement. OSHA references footcandles in older standards; IESNA/ASHRAE use footcandles for US applications. International projects typically use lux. Most modern light meters display both.

Safety/compliance surveys document that illumination levels meet minimum requirements (OSHA, ANSI/IES standards, or facility specs)—you measure at work surfaces, walkways, and emergency egress and compare to required minimums. Troubleshooting surveys identify why light levels are lower than expected (failed lamps, dirty fixtures, poor fixture placement) and guide corrective action. The measurement approach is similar, but compliance requires documentation of the standard applied and a pass/fail determination, while troubleshooting focuses on finding and fixing the problem.

Yes. High luminance contrast (glare) can cause visual discomfort and errors even when average illuminance meets guidelines. If workers report eye strain or difficulty seeing, consider a glare evaluation alongside footcandle readings.

Measure at the task plane—typically the work surface height (desk, bench, or floor). For general assessments, use a grid pattern across the space. Take readings with the meter level and in the orientation workers use the surface.

Use a fixed measurement grid, consistent meter orientation, and stable lamp conditions (let fixtures warm up before measuring). Document the grid layout so measurements can be repeated in the same locations during follow-up surveys.

Use a handheld meter for spot surveys and compliance checks across multiple locations. Use a data logger when you need to document how light levels change over time—shift lighting variations, daylighting effects, or equipment cycling.

Rent the LT300 (or similar lux/footcandle meter) for visible lighting surveys—workplace illumination, compliance checks, and lighting design. Rent the ILT2400 (or similar UV meter) when you need to measure UV intensity, specifically for UV-C disinfection verification, UV curing, or UV safety assessments. The two instruments serve completely different purposes and aren’t interchangeable.