 This paper discusses the importance of accurate luminance measurements when designing lighting installations. It explains how two different types of luminance meters, laboratory and portable, can produce significantly different results if the measurement distance is not correctly chosen. Additionally, it demonstrates how incorrect measurements can result in energy savings of up to 40% when using the wrong type of shade on a luminaire. Finally, it proposes a new test distance for luminance measurements using ILMD meters. This article was authored by Dariush Suzuki.