Question about exhaust fans, which one to get

[Penny21]

Hi guys! I'm in the market for a new exhaust fan for my grow box which is 0,54m³ or 19ft³ big. Currently I have an industrial axial fan with a capacity of 182m³/h or a cfm of 107 with a pressure of

4,18 mm H₂O.
The carbon filter is inside the box, directly connected to the fan which is outside of the grow box, sucking air from the box through the filter. I've built a muffler around the fan, and it makes the fan more quiet. I also have RPM control over the fan.

At full speed, the fan does its job, but keeps me awake at night because it's quite loud. And when I dial it down, the air above my LED lights (230 true watts) gets really really warm. The canopy is ok though, since I have a small fan moving around the colas. I want to move the whole exhause system inside the grow box, which is going to be a bit difficult since I don't have a lot of space.

I want to buy this fan:

https://www.hydroponics.eu/fans-and-...0m3h-9186.html
but in her article NebulaHaze http://www.growweedeasy.com/exhaust wrote not to get fans like the one I posted just now.

What appeals to me is that it has 2 settings, so I wouldn't need to buy a controller, also it's cheap and silent.

Another fan would be this one: https://www.hydroponics.eu/fans-and-...5m3h-9066.html

I live in Europe, so all the american made fans like Apollo Horticulture are not available here.

Which one do you think I should get?

[NebulaHaze]

Hmmmm, where did I say not to get a fan like that? I'm not familiar with that particular model but it looks like a good booster fan to me if you're trying to add to what the exhaust fan is doing Do you have any pictures of your plants in your setup and exhaust system? Sometimes it helps to see the space

[Penny21]

Hello, I'm sorry for the late reply. In the pictures attached, pic 1 shows the fan that is not recommended, because it would underperform. Pics 2-5 + 8 show my current set up and the last two pictures show the fans that I'm considering getting.

I want to completely replace the exhaust system, because I feel the current fan can't handle the setup. I've been lucky with smell, the two plants (Auto Jack and Auto Critical Rapido) don't smell too much yet, but they're flowering and I believe that this will soon change.

I want to have the fan as well as the filter inside the box. Basically Filter -> Tubing -> Fan -> Tubing -> Exhaust hole

[oldjarhead100]

Penny before you replace what you have try this I have the same filter/fan set up and my fan could be heard though the whole house. I'm assuming that the inline fan is screwed into a stud or joice so that its in direct contact with your house, well what I did was I took a bike tire iner tube and stretched it tight under the hanging bracket for the fan .then unscrewed the fan from the wall and let it hang down from the tube . no more noise. I hope I explained it well enough cause it will solve your problem

[Penny21]

Hey Oldjarhead, thanks for the tip! The fan is on top of the cabinet itself, but I've added rubber posts under the screws so the vibrations won't get transferred to the rest of the cabinet. I even tried reversing the whole set up so that the fan is inside the box and the filter is outside, but the fan isn't strong enough to push the air through the filter unless I up the RPM, which in turn makes it noisy as hell. The way it's set up right now is fine when it comes to sucking out the hot air. It's just noisy

I was just wondering whether getting a fan which is shaped like this: <-air out[====]<-air in (https://www.hydroponics.eu/fans-and-...0m3h-9186.html) would be worth it, or whether I should go for a round inline fan like this: https://www.hydroponics.eu/fans-and-...5m3h-9066.html

[NebulaHaze]

I personally think you'd be happier replacing your current fan with a better exhaust fan, as opposed to keeping an underpowered exhaust fan and adding an additional booster fan. A good exhaust fan will clear the whole grow space if it's cooling a 230W light, and you can turn the speed up or down if the fan comes with built-in speed settings (or you could get a speed controller). As far as reducing fan noise, the best thing I've found so far is hanging the fan from bungies attached to the top of the grow tent. Something about hanging the fan inside the tent as opposed to setting it on something really reduced the noise in my case (though I was just setting it on top of the tent before). I was able to keep the grow tent with the full-size fan on in my bedroom after that!

A word of warning: when shopping for an exhaust fan, just make sure to pay attention to the dimensions of the fan because they can be surprisingly big!

[oldjarhead100]

Penny the second one the one with the standing legs with a couple of rubber pieces under the legs but try the bungees like Nebula suggested never thought of them

[Penny21]

Thanks for the input you two! I think I understood the difference now between booster and exhaust fans. I'll be getting an inline fan and set it up with strings, like you suggested. I'm also going for a fan with built in speed controller, Blauberg makes them. I'll post back when I have everything set up, though it will probably be a week before it gets here.

[oldjarhead100]

penny not sure strings will work to keep it quite .rubber will absorb the vibrations that make the noise