Let's Talk Filter, Fans And Indoor Ventilation

7 days ago

Filter & Fans... Oh My!

After my physical therapy session today, I slid down to my favorite hydro-store (and wouldn't you know it- my favorite guy was there). I was thrilled to see this guy, as I like asking him questions as he is very thorough with his answers to me.

I was on a quest to see about using an indoor air filtration system for my grow room. I don't want to use an exhaust fan that ventilates outside; as I am never too sure who may be walking past my home. If I can keep it all (odor and knowledge of my grows) indoors, that's what I want.

So I had been researching the carbon filter and fans. But became confused with some of the mumble-jumble and I knew I needed my hydro-store guys.


What Are CFM's & How Much Do You Need?


  • First off, a CFM means cubic feet per minute
  • To determine what CFM you need for the room you looking to improve the air quality (or in this case, the smell), you need to figure out what CFM you will need.
    Here is a great place to figure out your needs
  • My room is 12x12 (more or less) and I was looking at the 1000-CFM filter system
  • You can use a fan (like the one pictured above on the right) or you can use a hurricane fan.
  • I want the fan to run 24/7 so I need to make sure it will be sturdy and stable on the bedroom floor. I do have the option to hang it from the ceiling, but we have cathedral ceilings and I'm just not too comfortable with a 50-lb filter system and fan hanging overhead.
  • The filter system I am considering is an 8-inch and the fan will also be an 8-inch with 420-CFMs.
  • Total cost will be about $275/USD (OUCH!) that hurts!

So now I save my money and hopefully in the next few weeks I'll be able to purchase the system.I will be looking online for cheaper priced systems now that I know what I am in need of.

I just want to eliminate most of the odor in the house. AS much as I love it... It does become annoying especially when I see people walking too close to my home. Better safe than sorry, right?

So I am curious.. what kind of system do you have? How does it work?

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amazing , i see you as someone who's really loving this thing and as i am reading your blog i also felt that this makes you happy and this really is your passion 👍

This is look so amazing and you write it very well

Nice post
Its not easy to grow cannabis indoor without enough ventilation

Great post - I used to have a family friend who grew, and ventilation was definitely an issue - especially when they were drying out a crop! Good luck in finding your air flow. :)

I only grow outdoor, one of the few topics I'll have no real imput on.

I see that your local hydroponics store is quite a bit larger than the one that is local to me. :-)
Ventilating to the outdoors without a filter is interesting, it carries that definite smell with the air, not a good thing if you want to be unnoticed.
I don't have a grow room setup, so I guess I don't have much input about it due to lack of experience with the equipment.

Wow 4 tents and no filter, get that sorted, you dont want curious people smelling that beautfull flowers..
You would want to exchange the air in your tent fully every minute,
So for example if your tent is 1.2m1.2m2m what is standard tent size, that is 2.88 cubic meters of air in your tent or 100 Cubic feet. So minimum air circulation should be 100cfm but cfm fan you should get is 120-130 cfm or 200 m3/h because carbon filter creates drag and reduces the fan efficiency by 20%. This is the minimum that plants need.

With hps because of heat the rule is divide your hps watts with 2 and that would be the number in cfm you are looking for. Example if using 600w get at least 300cfm fan or better 350cfm to be comfortable (20%). Filter needs to be inside of the tent and is connected via ducting to the fan. People usually keep them on top of their tents.

You could get a separate sets of fans and filters for each tent or scrub the whole room with a massive one.

I have in my 1m x 1m x 2m, can fan 320cfm w red scorpion filter of 300cfm.

Hope you get a good one! Good luck.