Small Light at Max Wattage vs Big Light dimmed

Hi all!

Still planning my grow tent. I’m curious: is there any advantage to buying a light capable of covering more sq footage and running it dimmed to 50% vs buying a smaller light and running it full blast? Is there any advantage in efficiency?

Heat is also likely going to be an issue for me. Would either scenario be cooler than the other? Would mounting the driver outside the tent help at all with heat buildup?



Oh yeah a big light turned down would save electricity and extend the life of the light. Plus you’ll have a bigger light for when you want to get a bigger tent. Notice I said when and not if :laughing:


Bigger lights give better edge coverage too, mounting the driver outside won’t really help, it’s the light boards and plants themselves that produce the most heat, you’re better off just making a more robust exhaust system. Besides the plants can handle temps of 99°F if you run a humidifier 24/7


What @MeEasy said :point_up_2: You will go bigger. I think we all do


One thing to watch for is physical size of the light I’ve seen a couple growers buy a light that didn’t fit in their tent, you don’t want to have it touching the tent

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Hey @Thumos I went with a bar style light that was a bit oversized for my environment. Also was able to move the driver outside of the tent. My local is quite hot and A/C is expensive so I had to move my drivers outside of the tent. I also just grow from late October until late April and lights on at night. I found that is the best way to stabilize my tent temperature and not run my A/C so hard. With two tents (4x4 & 4x9) I can get two goods runs each year. Just pulled last one out this week.


That’s actually good to hear as I anticipated humidity to be borderline too-high. Hot and humid here. Thanks!

Yeah, it only has a few inches all around it before touching my walls. Probably 3 or 4.

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That schedule makes the most sense to me. Hopefully after this one summer run, I’ll be stocked enough to move to such. For this. I’m planning to light at night. That’s about the best I can do if I’m determined to get one in now.

Did mounting the drivers outside help much? The smaller model I’m looking at has drivers mounted on the back of the board/heatsink. The larger one has extensions to it easy to mount elsewhere.

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Yep mounting drivers outside the tent is a tremendous help to control temps inside of tent. Pulling cold air from outside your tent during cooler months also provide fresh air too. The boards are going to be a source of heat you can’t get around. But then drivers can be a even bigger source of heat.

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Awesome data and advice. Thank you so much!

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You just about cant have to much light. My dual HLG 260 Rspect kit lights with UVA-30 are doing great in my 3’ x 3’ tent. They are both at 230 watts each out of 257 watts each with a ave. of 835 PPFD and a DLI ave. of 36.07. The runt plant at 750 PPFD and 32.40 is hurting the ave. pretty bad tent wise. If I elevated the runt it’s numbers would be more like 850 PPFD and DLI 36.72. If I had only one 260 in the tent I would be maxed out and needing more.

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