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A customer recently asked us about LED grow light tubes. They mentioned that they used T8 light bars with SMD 2835 LEDs in a previous project. The lights gave off so much heat that the temperature in the grow room shot up—water and air temperatures both climbed above 30°C (86°F).
In the end, they had to use air conditioners just to bring it down below 23°C (73°F). The electricity cost for the AC alone was crazy. It felt like they had to pay an “air conditioning tax” just to grow vegetables—who can afford that?
As soon as I heard that, I knew something wasn’t right. And I asked for more details about the T8 lights.
Turns out they were using 120cm (4ft) T8 tubes with 36 watts of power each! No wonder they were overheating.
You read that right—T8 tubes running at 36W. Sounds powerful, but honestly, T8 light tubes are not built for that kind of wattage. These tubes just weren’t designed to handle so much power.
Some customers do not understand how lighting systems work. They see a few specs—high wattage with a cheap price —and think it’s a great deal.
But when you run a T8 grow light at 36W, everything is pushed to the limit: the LEDs, the driver, the aluminum housing.
After a while, all sorts of problems start to show up:
Then you have to crank up the air conditioning, and suddenly the cost goes through the roof.
You might’ve saved a bit on the lights, but now you’re paying more for AC, repairs, and reduced plant yield. In the end, your total cost could easily double—or worse.
Generally, for a 120cm (4-foot) T8 tube, 18W to 20W is the sweet spot. That’s where the power and heat balance out nicely.
Push it beyond that, and the cooling can not keep up—then you’re asking for trouble.
If you force 36W into a T8 tube, don’t be surprised when it starts running hot.
If you need high-power grow lights, here’s the honest answer: go with T10 or T15 tubes instead.
A customer once asked me, How much of the wattage ends up as heat?
Great question. Reducing heat is not just about the lamp housing—your choice of LEDs matters too.
For example, this customer had been using SMD 2835 LEDs. They’re cheap, but they run hot.
Here’s how we improve on that:
With quality LEDs and smart design, we can keep heat output below 55% of total wattage. That small drop in heat can save you a lot on air conditioning costs.
I get it—there’s a lot of flashy marketing out there. Some companies push “high wattage at a low price,” and that’s what attracts certain customers. But later, they came back to us asking for a full redesign because their setup didn’t work out.
It’s just like farming: if you cut corners on soil and seeds, you end up wasting both time and money.
I run a grow light manufacturing business, but I’m not here to oversell. I’d rather help you pick a setup that truly fits your environment—something energy-efficient, reliable, and built to last. That way, you avoid a lot of headaches down the road.
Choosing a light isn’t about who offers the highest wattage or the cheapest price. It’s about what works best for your grow room.
If you’re currently using T8 grow light tube—or planning a new project—let’s talk. Maybe we can find a smarter, more dependable solution together.
From custom light planning, to tailored quotes, and everything in between, our team of horticulture experts are always ready to assist.
Vanten LED
Guzhen, Zhongshan, Guangdong, China
WhatsApp: +86 180 2409 6862
Email: info @ vantenled.com
We are a professional LED plant light manufacturer, committed to using technology to enhance the maximum potential of the lamp, continuously maximizing the benefits for growers, and saving energy for the planet.
