Are You Saying It Right? Understanding the IES Definitions of Lamp, Fixture, and Luminaire

By Patrick Harders, LC

Most of us in the landscape lighting world have been guilty of calling every lighting product a “fixture.” I know I have. But here’s the thing: it’s not technically correct. And understanding the correct terminology can save you time, reduce service calls, and help you choose the right product for your jobs.

Our latest video breaks down how the Illuminating Engineering Society (IES) classifies lighting components and why it matters.

Watch the full video here:

Here's a quick overview:

1. Fixture + Lamp

This is what most of us started with. It’s a housing that holds a lamp. Think drop-ins, think retrofits. A brass or aluminum body and a lamp sitting inside. You screw in the bulb, you’re good to go… for a while.

• Easy to service? Yes.

• Long lifespan? Not so much.

• Heat dissipation? Poor.

This setup doesn’t typically include built-in heat sinking, which means you're probably cutting the expected lifespan of your LED in half right out of the gate.

2. Integrated Non-Serviceable Luminaire  

Now we’re stepping up. A luminaire is a product where the light source has been designed into the body of the unit. No bulb swapping; it’s all-in-one.

• Optimized for performance

• Better thermal management

• Best space utilization

The downside, however, is that should the LED or driver fail, there is no ability to service it. I know this from experience: I had to deal with pourly designed fully integrated luminaires.

3. Dedicated Serviceable (Modular) Luminaire  

This is where Sterling Lighting comes in. We created a third category that is:

• Fully dedicated for heat dissipation and maximum LM70 results

• Modular, plug-and-play components

• Field serviceable for quick service calls

A dedicated LED is high performance while easy to maintain. When you have a complete unit with a driver, LED and house makes an IES defined luminaire.

Why the Terminology Matters  

I know some people might be thinking that this seems like a technicality that doesn't deserve so much focus. But here's why this is actually important for strategy in addition to semantics.

When I scaled my own landscape lighting business, I had to pick a product line I could trust. Something consistent, scalable, and low-maintenance. When I used lamp+fixture combos, my service calls doubled. When I went all-in on non-serviceable luminaires, which in theory should have been far superior, the engeneering had a long way to go.

With our serviceable luminaires, we’ve engineered a product that:

• Reduces callbacks

• Keeps lumen output consistent

• Saves your team time in the field

We believe this is the most environmentally responsible and professionally reliable solution out there.

 Here’s your practical takeaway: 

• Know your terminology. Clients may not care, but you should because it informs your buying and installation decisions.

• Think long-term. Products that fail prematurely aren’t just frustrating. They erode your brand.

• Keep it simple. Stock modular components in your service vehicle and fix issues in minutes rather than hours.

The next time someone calls a luminaire a fixture, gently correct them. Or just send them this video.

Let’s elevate the language and standard of our industry.