8" inline fan enough to cool 3 1k Gavitas, 18x18 room, ambient temp 65 all year long?

I’m setting up a veg space, its 18’x18’ room with 8’ ceilings. Temps all year stay around 65 degrees. I plan to run (3) 1k Gavitas DE in this space. Do you think a 8" fan rated at approx. 800cfm would be enough to keep temps in check? Fan will be connected to a carbon filter and incoming air is via passive intake and is around 65 degrees all year long.


I’d say no unless your gonna run the lights at 500 watts and even then the temp will climb gavida lights put out a lot of heat .


You might be alright with the cool intake air. Why such a large space? If you cut it down to like 15x5 where the lights are you’ll be at around 600 cubic feet of space which the fan should exchange once a minute.

Also you’ll want to dump the hot air somewhere else, if you put it back to the intake area it will get warm fast.


That’s a lot of veg space

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The hot air will be exhausted outside. The incoming air is coming from a lung room that stays cool all year long.

Its a big space but within the space also is a clone rack, rack for supplies/nutes etc, (3) 265 gallon reservoirs that take up a 4’x4’ space each, plus a stair structure. It sounds like a big space but my veg table is 7’x16’… I plan to run the “spread” on the gavitas over the 7’ section.

Reason I’m specifying 8" is because a friend’s got a pallet of 8" fans… worse case I grab 2 8" fans to deal with the heat. The two fans combined are way more efficient than any single fan pushing 1600cfms.


From my experience with them Gavitas on the 1k setting don’t put out any more heat than a standard 1k single ended bulb. I think when people say Gavita’s put out more heat, maybe that[s on the max 1150 setting? Feel hotter and actual temperature are two different things… 1watt = 3.41btu, don’t matter the source, single or double ended.


I think you may be okay. People over exaggerate the heat from gavita a bit they throw heat but are designed that way because greenhouses run cool and even run co2 generators as a 2nd secondary heat heat source. I find its easier to air cool them than cool them with AC in a sealed area. with 8 foot ceilings you may be cutting it close, the more headroom you have to buffer heat the better. if not you have to make up for it somehow.


I think you can get away with it no problem, since your ambients are so nice. It may be nice to have a second one depending on how far/how many turns the duct has to exhaust, or for extra ventilation should you need it.

You’ll probably need to run it close to max setting, two on a lower speed would be nice for redundancy and noise reduction.

I can cool a 1K with a 6" on less than 50% speed, 3K with an 8" at near full bore should be no problem at all.


I’ve never used double ended but I’ve ran 3 normal 1000w hps with two inlines one at each end of the lights in a room pretty close to the size of your veg table when it’s not summer, come summer it can only run two lights with a window unit a/c but it’s a brick oven of a house

I would pick up 2 try it with one if you want but if you can get a deal on them fans I would grab a couple then if one does work you have a backup


I would definitely like to hear how it goes, I have a 12 x 17 room with 8ft ceilings.


I agree with this. My 750’s run amazing on 600 and are supposed to be just as efficient at 750. If I crank em all up to 875 I experience heat issues. I’ve ordered more btu to test what is required to achieve 78f at 750 x3-4 for myself in my 10x10 ish 6-6.5 foot space (accounting for floor joists areas which are used to compensate for ballast height)

Cheers for the wattage to btu calc.