Cold air intake idea? Will it work?

Don’t laugh but my grow room is in a steel building where I built a room in the corner of it. The room is 5x7 but growing in a 5x4 section. the room is insulated floor as well but outside the room is a gravel floor I’m wondering instead of getting a ac unit out there if I could dig a 3ft deep x 3 ft long trench and put a 6” pvc pipe down there and connected my duct work to it how much cooler it would make the intake air?

And here is my room

Yeah it will work. As to how well. I don’t know. But the air is always colder under ground and therefore if pushed into the room would cool it down in theory.

You will want as much duct as you can fit in a snake like pattern like an underfloor heating system.

Covering as much surface area as possible. Like so.

Maybe get two intakes so they are pulling slower through the underfloor duct.
Make sure its sealed well.

Never tried this like but it should work. A good fan should be able to cope with the resistance.

I dont even want to do the math of how long your ducts have to be to cool that amount of air to notice anything.

BostonBuds said:

I dont even want to do the math of how long your ducts have to be to cool that amount of air to notice anything.

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Do the math man! Do the math..

corbin5754 said:

And here is my room

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What are the temps like in that steel building anyways? How low do you think you need the intake air, seeing as it appears you have zero issues with being able to exhaust any hot air created by lighting.

Buy a portable A/C unit. Look online there not very expensive. A good exhaust fan alone can cost nearly as much. I bought one call Avista that got a very good review for like $200.

I’m just now starting my setup and with outside temps in the 40s right now the grow room stays at 77 degrees and I imagine when outside temps temps get higher I’ll need ac or just fresh cold air. I might be alright through April and May but June July aug it will be hotter

Blue back said:

Buy a portable A/C unit. Look online there not very expensive. A good exhaust fan alone can cost nearly as much. I bought one call Avista that got a very good review for like $200.

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I’d like to find a ac that draws the least amount of power

My building is in the shade and my grow room is insulated I might not even need an ac just a cold air intake and exhaust I’m running 2 400w leds

In the winter here in Michigan my A/C hardly ever kicks on with the door opened. Not often in the summer either with the house A/C on. I run 2 315 CMH's and A 6 bulb 4' T5 in a 10' x 4' room.

Since this is the first grow at this location I’ll just have to play it by ear. I’m doing a white widow auto grow.

corbin5754 said:

I’d like to find a ac that draws the least amount of power

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A minisplit. They only run as hard as they have to using inverter technology they can run the fans and compressor just enough to do the job. Normal AC units are either on or off, no in between.

Renfro said:

A minisplit. They only run as hard as they have to using inverter technology they can run the fans and compressor just enough to do the job. Normal AC units are either on or off, no in between.

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Not mine. When it's on its on. The fan runs my exhaust. When its lower then the ac setting the fan remains on. Also has a dry setting.No heat though.lol

corbin5754 said:

Don’t laugh but my grow room is in a steel building where I built a room in the corner of it. The room is 5x7 but growing in a 5x4 section. the room is insulated floor as well but outside the room is a gravel floor I’m wondering instead of getting a ac unit out there if I could dig a 3ft deep x 3 ft long trench and put a 6” pvc pipe down there and connected my duct work to it how much cooler it would make the intake air?

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Ive seen stuff like that done to cool and heat homes. A few foot down and the ground is a constant temp year round.

It will work but you will need a longer run and most likely a different material for the pipe. Maybe metal for quicker heat exchange.

A run of 20-30 foot would be needed and then snake it back and forth to make it double or triple that in actual length.

Even if you had to go outside the building no big deal as you will be burying it.