When you’re planning out a building’s lighting system, one of the biggest questions is: how much energy are those lights really going to use? That’s where Lighting Power Density (LPD) comes in. Think of it as the scorecard for your lighting design. It indicates the amount of electrical power used for lighting per square foot (or square meter) of space.
Why does this matter? Because energy efficiency isn’t just about saving money on your utility bill — it’s about meeting building codes, boosting sustainability, and even improving comfort for the people using the space. According to the U.S. Department of Energy (DOE), lighting can account for up to 17% of total energy use in commercial buildings, meaning that every watt saved makes a measurable impact. The lower your lighting power density (without sacrificing brightness), the more efficient your design is.
In this guide, we’ll break down what LPD really means, how it’s calculated, the standards you need to know, and practical tips for keeping it in check. Whether you’re an architect, a contractor, or just someone curious about energy-smart design, this guide will give you a clear, simple explanation without the jargon.