6 Ways to Know Your LED Fixtures are Ready to be Replaced

LED Fixtures don’t just burn out overnight; they fade, degrade, and eventually underperform. Now what’s the reoccurring problem? Many cultivators don’t realize it until their plants start telling them. Here’s how to spot the warning signs before it starts affecting your canopy.

1 – Dimming Output

What it looks like: Your plants are not performing like they once did. Slower veg, smaller flower, or inconsistent yields, without any changes in your light schedule or nutrient intake.

Why it matters: All LED diodes slowly degrade over time, even in high-quality fixtures. This results in a gradual drop in PPFD (Photosynthetic Photon Flux Density), which means your plants are receiving less usable light energy than they actually need. To the eye it might not look that way, but your plants will!

Test it: Compare your current PAR or PPFD readings to the ones taken when the lights were first installed. If the reading dropped from 10 to 20%, it’s a clear sign that your fixture is past its prime and is affecting plant performance, especially in flower. It’s important to note that this should not be happening until your fixtures are 5 to 15 years old (depending on fixture quality).

2 – You’re Still Running Blurples or Fan-Cooled Lights

What it looks like: If your grow room is glowing purple or your fixtures are constantly humming from internal fans, it’s likely time to upgrade. We’re not here to tell cultivators how to run their grow but after seeing countless preventable issues in the field, we can confidently say: outdated LEDs can quietly hold your grow back.

Why it matters: Blurple lights were popular in the early days of LED growing and were once cutting edge. Since then, newer studies show that a broader, full-spectrum (‘white’ light) output, including blue, red and all the wavelengths in-between lead to more compact plant morphology, stronger cannabinoid expression (like THC, CBD, and CBG), and more consistent flower development. Blurples also have difficulty noticing deficiencies, diseases and pests while caring for your crop. Fan-cooled fixtures are also a red flag. Passive cooling heat sinks are now the industry standard for a reason: no noise, no failure points, better reliability.

Test it: Take a look at your fixture’s specification sheet or spectral output. If your light is primarily purple, lacks a white/full-spectrum range, or includes an internal cooling fan, you’re running outdated technology. That means lower plant performance, no rebate eligibility, and a higher risk of failure mid-grow. How can you expect to reach your plant’s full potential if your lighting tech can’t keep up?

3 – Poor Canopy Penetration

What it looks like: Lower leaves and buds are weaker, underdeveloped, or dying off entirely. Top colas might still be performing, but they’re often the only ones thriving.

Why it matters: As LEDs age, their light output and optical performance decline. Older models may also lack optimized lensing or beam angles designed to push photons deep into the canopy. Without proper penetration, your under-canopy becomes non-productive, airflow gets restricted, and your overall yield potential drops. All while you’re still paying for electricity those zones aren’t benefiting from.

Test it: Take PAR or PPFD readings at different canopy levels! If the lower sections are showing significantly less than they did when the lights were first installed or are falling below the effective threshold (typically around 800 PAR in flower, depending on your setup or scale) — your light isn’t doing its job anymore.

4 – The Fixture is 10+ years old

What it looks like: You’ve been using the same LED fixtures when they first became popular over a decade ago. They still turn on, but its performance has slowly declined and you might not even notice it until you compare newer results side by side.

Why it matters: Like we mentioned earlier, LEDs do degrade with time. After 8-10 years, light output, spectrum consistency and efficiency all decline over time, even if the fixture still powers on. Which can directly affect plant morphology, cannabinoid content, and yield. Let’s face it, LED tech has come a long way and will continue to do so. Today’s fixtures are more energy-efficient, spectrum-optimized, and designed for better canopy penetration than anything from a decade ago. In 2022, 88% of cannabis cultivation took place in indoor facilities, making it safe to say that LEDs are the future of this industry.  

Test it: Check your installation date. If it’s been over 10 years, your lights are likely underperforming, even if they haven’t failed completely! Compare energy consumption, PPFD output, and yield data from past years. If you’re seeing declining returns, it’s time to upgrade.

5 – You’re Missing Out on Rebates

What it looks like: If your fixtures don’t meet DLC or utility energy-efficiency standards, and your grow is eligible for upgrade incentives.

Why it matters: Rebates can significantly offset the cost of new fixtures — but only if you’re using eligible, certified tech. Newer LED models are engineered to meet the efficiency standards and deliver improved spectrum performance that directly benefits your plants. If your current lights aren’t on the list, it’s time to upgrade because you’re missing out on both rebates and performance. 

Test it: Visit our rebates page or check your utility provider’s list of approved products. If your current lights aren’t listed, you’re missing both money and performance.

6 – Your Warranty Has Expired

What it looks like: Your lights are out of their 3-5 year warranty window, and you’re on your own if something fails.

Why it matters: Fixtures tend to start to degrade around the time their warranty expires. If your lights go out mid-cycle, the downtime and crop risk outweigh the cost of replacement. Plus, older tech often lacks the spectrum design that newer LED science supports.

Test it: If your warranty has expired, don’t wait for a fixture to fail mid-run — start planning your replacement before you’re forced into it.

Make the Switch

To wrap it up, LED fixtures don’t reach end-of-life quickly, but they do wear out quietly. When they do, the real cost isn’t the fixture — it’s the lost yield, inconsistent quality, and wasted energy that adds up overtime.

Staying ahead of these warning signs means giving your plants the consistency they deserve to thrive, the reliability your team needs and the ROI that your business expects. Whether it’s dimming output, outdated tech, or spectrum loss, don’t wait until your plants are the ones telling you there’s a problem. If you’re seeing any of these signs, it might be time to rethink what’s hanging above your plants. Contact us at sales@aeliusled.com for any inquiries.