T5 HO actually harder to cool than HID?

I live in a very warm climate so I figured i'd get a Quantum badboy 8 Tube T5 HO fixture so i wouldn't have to deal with so much heat in my tent. What i'm noticing now is that the T5 definitely generates more heat than I expected, and it's actually not that easy to keep it cool.

Even though I have a 420+ CFM fan in my 4x4 tent, the heat from the T5 light kind of just floats around under the light so I have to keep it at least 1ft away otherwise it will shoot up to 95-100 degrees under the light real fast. The ambient temp in my house is around 70F right now. I also have two 6" fans blowing up directly onto the tubes, and a 12" oscillating fan inside the tent. With all that, i'm just barely able to keep it around 85 degrees under the light.

Now this brings me to the big question.. although HID lights generate a lot more heat than the T5, is it possible that i would actually have less heat problems using a 600 watt HID instead of the T5 since i'd be able to just duct the heat right out the window?

I assume your 420CFM fan is an exhaust, correct?

If you get an HID, invest in an enclosed hood and you should be fine. That way you can direct all the heat elsewhere via the ducting.

Auzzie07 said:

I assume your 420CFM fan is an exhaust, correct?

If you get an HID, invest in an enclosed hood and you should be fine. That way you can direct all the heat elsewhere via the ducting.

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Correct, the fan is for exhaust which is mounted at the top of the tent.

where is the thermometer when you take the temp. sometimes if the light is shining directly on the sensor it can give a falsely higher reading.

irieie said:

where is the thermometer when you take the temp. sometimes if the light is shining directly on the sensor it can give a falsely higher reading.

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Also a good point!

Thermometer should be at canopy-level.

irieie said:

where is the thermometer when you take the temp. sometimes if the light is shining directly on the sensor it can give a falsely higher reading.

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I'm using this thermometer with the probe:



I have the probe hanging under the light right at the height of my seedlings. The light is directly hitting it, but it feels cool to the touch though.

It seems like lowering the ambient temp is best for T5HO lights instead of focusing so much on trying to exhaust the heat from the tent. I'm thinking about trying out a cooling setup with a 1/4HP chiller and an ice box with a 5 gallon bucket for a reservoir to see how much I can cool the room. If it can generate cool enough air, I might even be able to just leave the tent sealed.