Forced Induction vs. Natural Aspiration...?

**B1unt** · 25-06-21, 09:47 AM

Originally Posted by Farmer Geddon

My 8" L1 rvk is quoted at 960m3/h. Overkill for a grow cupboard of less than 2.5m3 but I was broke and it was to hand. It runs at 40% power and seems to drop the RH by 5 points or so.

I can drop humidity with my exhaust fan (although it seems redundant over 50% power as that seems to bring the tent to ambient levels).

And if ambient levels are 60% + plants transpiring that means the dehumidifier has to come out. Which I accept, however I am not a fan as of the space it takes up, the heat it gives off & the power it consumes.

**Farmer Geddon** · 25-06-21, 01:38 PM

If not having climate control put me at risk of running dry, I'd do it. Lower yields will keep me in smoke so whatever the climate happens to be, it can stay that way.

Luckily(?) for me, this is a cold flat. At least 6'C colder than outside so never a problem with heatwaves.

**Deku Nut** · 25-06-21, 01:53 PM

Originally Posted by B1unt

Sorry mate, was high as F’ & couldn’t compose a response to this that made sense.

Basically I am trying to work out of having an intake improves cooling, over just an exhaust?

No worries man. I honestly don't believe an intake fans helps much other than let you get air from a different area than you are in, or if your exhaust fan is too small for your tent it could assist air exchange.

**Jingo** · 25-06-21, 05:08 PM

I haven't used my groom in about 3 years, but I had a 10-in extraction and a 6-in intake. Usually about halfway through the summer I would turn on the intake fan, it really helped.

J

My 2020 outdoor grow autos and photos in pots

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**gardro** · 25-06-21, 05:46 PM

All very very groom specific and depends on the required airflow and how much resistance there is to that.

The extractor fan has to "pull' the air through the inlet so you should consider the duct (resistance) as the total of the extract plus inlet path.

So you could have a 12 inch fan moving less air than a 4 inch in extreme cases.

At the limit, if you were to never use an inlet fan, a 12 inch fan could implode a duct, crushing it flat if there was too much resistance, unlikely but just shows why you need to push inlet in. Push pull arrangements work well.

In an average tent setup in a house, inlet push is probably not needed. That is unless you are extracting up a block of flats and pulling air from next door but two's cellar.

**B1unt** · 25-06-21, 09:09 PM

Originally Posted by jingo

I haven't used my groom in about 3 years, but I had a 10-in extraction and a 6-in intake. Usually about halfway through the summer I would turn on the intake fan, it really helped.

When you say "it really helps" does this include lowering humidity, opposed to just the passive intake?

Cheers,
B1unt

**Krofam** · 25-06-21, 09:42 PM

came in here thinking it was about engines.

passive intake for me.

**B1unt** · 25-06-21, 10:11 PM

Originally Posted by Krofam

came in here thinking it was about engines.

passive intake for me.

At least someone got it

**Jingo** · 26-06-21, 02:08 AM

Originally Posted by B1unt

When you say "it really helps" does this include lowering humidity, opposed to just the passive intake?

Cheers,
B1unt

Humidity isn't an issue where I live I was always happy if I had 40% by the time I made it into flower. Normally I would veg at about 25% until the groom started filling up with a bunch of vegetation.

J

My 2020 outdoor grow autos and photos in pots

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