Flos Fixture Specification: A 6-Step Checklist (With the Grow-Light Answer)

I'll start with the uncomfortable part. I've been specifying interior lighting for twelve years, and I've personally made enough mistakes to fill a folder I now call “the tuition folder.” Roughly $14,000 worth of rework. That's not a flex. That's a reminder.

Most of that money was wasted because I skipped a check, not because the fixtures were poorly made. In 2017, I specified a Flos Arco lamp for a reading corner in a client lounge. It looked perfect on the rendering. Then the electrician called: the outlet was too far, the ceiling soffit was in the way, and the marble base couldn't sit flush because of the floor outlet. What should have been a 2-hour installation became a three-day project. The change order was $900 and included a plinth, an outlet relocation, and a custom spacer. That's when I created the checklist below.

This is for anyone who's about to specify or buy a Flos fixture — architects, interior designers, and owners who don't want to repeat my mistakes. It has six steps. Follow them in order.

The Six-Step Flos Fixture Checklist

Step 1: Measure the site before you measure the fixture

From the outside, specifying a Flos Arco lamp looks like a simple exercise: pick an iconic design, put it in the drawing, done. The reality is that the fixture has a heavy marble base, a long cantilevered arm, and a shade that needs to move. If the base is placed near a floor outlet, or the shade can't swing without hitting a bulkhead, the fixture won't work the way it should.

On that 2017 project, I had the product data sheet in front of me. I just didn't compare it to the actual site conditions. Now I take a tape measure to the space before I write the schedule. The extra ten minutes has saved me more times than I can count.

Step 2: Know the difference between a statement and a workhorse

A Flos Arco lamp is a beautiful task light. It's excellent over a dining table, a desk, or a reading chair. But it's not a wall washer, and it's not a general-purpose spotlight. If someone says “we need a Flos fixture for the lounge,” the first question is not about aesthetics. It's about what the light needs to do.

For accent lighting on a specific surface, a track spotlight or a wall-mounted spot is usually the right choice. For ambient light over a lounge seating group, you're often better off with a low-glare pendant or a row of covered spotlights. The model name matters less than the job.

Step 3: Don't treat the spotlight cover as optional

This is the step that surprises most people, including me once. The word “cover” makes it sound like a protective cap you throw away after installation. It's not. On the Flos Spotlight track family, the cover is part of the optical system.

When I compared two identical Spotlight heads side by side — one with the cover and one without — I finally understood why the details matter so much. The covered head produced a clean, controlled beam on the table below. The uncovered head created a glare streak on the polished floor and a washed-out wall behind it. Same fixture, same height, same angle. The only difference was a piece of formed metal.

If you're specifying a Spotlight Lounge layout — a low-glare accent row aimed at seating — the spotlight cover belongs on the order before the fixtures do. The cover is not a decoration. It's the thing that makes the word “spotlight” true.

Step 4: Confirm dimming and driver compatibility before you buy

It's tempting to think a light is a light. But the “just pick the pretty one” advice ignores the difference between standard drivers and dimmable drivers, and between leading-edge, trailing-edge, 0-10V, and DALI. Flos offers different driver versions depending on the fixture and control system. The wrong driver will cost you a week and an extra invoice.

I once ordered a non-dimmable version of a Flos fixture for a conference room on a 0-10V dimmer. The client noticed the flicker immediately (of course). The replacement driver wasn't stock, so we waited eleven days. The fixture was beautiful. The process was not.

Always check the fixture code and the driver code on the data sheet. Per the Flos technical data sheets I accessed in March 2025, the driver is listed as part of the exact fixture code. Verify your specific code, because specs do change.

Step 5: If the space has a grow light, answer the “how long should seeds be under a grow light” question on day one

This sounds off-topic for a lighting fixture article, but it's not. I once had a client add a tray of seedlings to a lounge that already had a small spotlight track and a beautiful Flos Arco lamp. They tucked a cheap grow light behind a planter and asked me to “make sure it's on enough.” The first question should have been: how long should seeds be under a grow light?

The short answer is 14 to 16 hours per day for most seedlings, with an 8 to 10 hour dark period. Some growers push to 18 hours for leafy herbs, but 24-hour light is rarely better and often worse. Seedlings need the dark phase to rest and develop roots. Leaving the light on all day can also cook the soil and blow the electric bill.

So if you're coordinating a lounge with plants, treat the grow light like any other fixture. Give it a circuit, a timer, and a written schedule. A $15 outlet timer is cheaper than a tray of leggy seedlings and a client who has lost patience.

Step 6: Order the covers, accessories, and driver modules in the same purchase

I still make this mistake in small ways, so now I have a rule: if the fixture needs an accessory, the accessory goes on the same order. For a Flos track spot, that might be the spotlight cover or a different track adapter. For a pendant, it might be a longer cable or a canopy hardware kit. For any fixture, it's the exact driver module.

We've caught 47 potential errors in the last 18 months using this checklist. Most were small — wrong adapter, missing cover, mismatched dimmer. But small errors become expensive when they're discovered after the fixture is hanging from the ceiling.

Final notes from the mistakes folder

A few things I do before signing off on every lighting schedule:

• I physically check the room conditions and take photos of the ceiling, floor, and nearby obstacles.
• I save the product data sheet PDF and the order confirmation in the project file, not in my downloads folder.
• If the project includes a grow light, I set the timer before the seeds arrive. I do not trust a client to remember to turn it off.

To be clear, I do not mean every project needs every accessory. But every decision needs to be written down. Five minutes of verification beats five days of correction. That's the lesson that cost me about $14,000 to learn.