When it comes to growing, I think the most important thing is the ventilation and the odour control. That's possible the first thing that I would think of before even deciding how big my growing space will be. And you need to be able to deal with a few things before starting anything else.
Depending on your grow room size, you will need an extraction fan which should be able to replace the air volume of your grow room about 3 times in 1 minute. And then you will need a Carbon Filter which is highly rated than your extraction fan. And least but not last is ducting. Having these 3 things and negative pressure in your grow room, you are nearly there to guarantee no smell leaks.
Extraction fans
There is such a huge variety of fans on the market. To guarantee your security you need a powerful fan that can keep a negative pressure in your tent. To be able to know what size fan you need for your size grow room you need to calculate the volume of the groom. Once you know it you start browsing for a powerful fan. I would recommend buying much more powerful than you need so you're able to turn it down via controller. A 4'' fan working on 100% will be noisier than a 6'' fan working on 50%. Now you can find boxed fans, acoustic fans and etc. Of course they are more expensive than the normal ones but are much more quieter. If you're good at DIY, you can get yourself a normal fan and build a box for it. It is very important to be sure that your neighbours can't hear the fans as it's the second most common giveaway after the smell.
Carbon Filter
One the most important things in growing is getting rid of the smell. And nothing does a better job then filtering your extracted air through a Carbon Filter. There are many on the market these days But I would stick to the ones tried and tested by members. Rhino Pro was a leading brand for many years but lately they are struggling to keep up with the quality the used to provide. It's very important your Carbon Filter to be Highly rated than your fan, simply because if you push more air through the filter than it can handle you will have smell leaks. Best thing to do is to get much bigger fan and filter than you need and run them on 50%. Guaranteed it will last longer and will filter all the air going through it. Don't forget to replace your filter regularly. It can be expensive but will keep you safe! The best way to use these a carbon filter is to suck air through it rather than pushing, as this eliminates the risk of leaks through the ducting.
Ducting!
This can be tricky. There are few different types of ducting depending on how much you are ready to spend. And I would recommend spending a little bit more!
Starting with the aluminium - I won't pay much attention as I won't recommend it. Reasons? Too noisy, not reliable, easy to damage.
Next stop is the Combi ducting - it has an aluminium and polyester inner shell. Better choice than the aluminium, but still noisy.
Third stop is Acoustic Ducting - That would be the ideal ducting to use. It can be proper pain in the ass to set up but it's worth every penny and minute spend settting it up. Reduces the noise a lot!
Forth choice is something new PhonicTrap Ducting - that would be the perfect choice. It's like Acoustic and Combi ducting combined but It's 3 layers thick and has no glass wool. Definitely my next buy!
Additional extras that can help you reduce the noise coming from the ducting are silencers. They are pretty cheap and do awesome job. Remove the whooosh effect instantly.
And last, don't forget to regularly check if all ducting/fans/filters and linked properly together and there are no gaps/tears in joints. Keep safe people!