What size carbon filter and fan should i use?

Hi everyone,

I'm new to the forum and as such i'll take the time to introduce myself. I'm smokerfromholland, so as you will have guessed im from Holland, aaand ive been smoking the good stuff for about 5 years now. Let's clear a common misconception first. Smoking in Holland is NOT legal. Police will not prosecute people who smoke weed, but possession of weed is an offence punishable by as much as a 3-5 yr prison sentence (depending on the amount of ganja that you're carrying around). As such, certain groups of people in my country are prohibited to smoke weed (i.e. the military, police officers etc.)

The fact that only the smoking (and not the possession) is sort-a-legal (even for smoking you'll be fined if caught, police officers call this a domestic disturbance..) means that my landlord can prohibit me from smoking in or around my house. Since i'll be kicked out if he catches me, i'll just have to 'not-get-caught' eh?

So that's what brings me here; now i think i might be in the wrong section here but bear with me. I was thinking of building a carbon filter (with fan) for my living room, so i can smoke there and not have to worry about my neighbours (who share a hall with me) smelling my greens. The problem is that there's an awfull lot of products on the market, and also a lot of people explaining 'the best way' to set this kinda thing up. Also, my living room is fairly large and as such i'm not sure what to get. Since i'll get kicked out if my landlord gets just 1 complaint, the margin for error is very very very small. Actually there's really no margin at all.. so on to it then:

for a room thats 6 x 5 x 2.5 meters (length, width, height) (or 16 x 20 x 8 ft, for the american smokers out there), how big should my fan be, CFM wise? i've read some stuff about this and it appears that some smokers/growers prefer a CFM that is about 5 times the volume of the room so that it'll exchange the air 5 times a minute. On other forums i've read it should be more like exchanging the air once every 3-5 minutes.. i'm not sure what i should go for? exchanging the air 5 times every minute would mean one hell of a fan and filter wouldnt it?

Anyways, i'm also struggling as to what size filter will be compatible with the right size fan, anyone got pointers on how to calculate this stuff?

As i said, probably in the wrong place here since technically i aint growing stuff, but since the filter and fan stuff is part of growing i figured: these guys probably know this stuff, better try here!

I hope you can help a fellow smoker out!

Greetings from Holland!

A inline fan in the living room is going to sound like a jet taking off lol.. As for what filter and fan.. You look at the rated com they have. Say the filter says 500 cfm, you need a fan rated at 500 or less cfm for it to work correctly. You fan cfm can't be more then your filters cfm

since your not growing (and this is just MHO) I don't think you need to change the air every 3 minutes (unless your burning a hole tree LOL ) you could gauge the air draw with (dare I say it ) cigarettes or one of those smoke bombs they test ventilation ducting with. Might piss them off but they can't bust ya for something like that. ha ha I sure other's will have better ideals just my .02 worth

hi smoker from holland,

i have often wondered the same thing , i would like a similar set-up in the room where me and my pals smoke it up.

i would say that smoking one joint creates more smell than a tent full of mature plants, the smoke seems to permeate the air and find any tiny gap to escape. how many people here used to get high in their room, shoving a towel under the door whilst hanging out a window and the whole house would still stink of weed!.

personally i don't think it would work very well in a large room like that, it would have to be a fairly powerful fan and you would have to sit near (or underneath blowing smoke towards the filter). even then there would be a lot of smell in the fumes that you can't see with your eyes as well as the noise of the fan pushing air through ducting.

you fail to mention the health benefits attached to not sitting in a smoke filled environment too, i think every smoking room should have one.


if i were you, risking your neighbours reporting you for funny noises and smells in your apartment, you might as well be growing, just get high in the tent with the plants!.

good luck and let us know how you get on with your project.

@ ghb: lol yea thought of that but i've read somewhere that the tar and nicotine is bad for the buds? I'm not sure whether this is true by the way..

Anyways guys thanks for your replies! i've been doing some research myself aswell, and i think i might just have to build a prototype of some sort. I have found out that i am actually looking for a carbon scrubber, since the air wont be leaving the room. (i dont want to have to make a huge hole in either my outside wall, or the wall next to my neighbours front door )
Though, i'm affraid this setup will cause some problems.. i mean, it's gonna be hard to create the negative pressure needed to suck all the air through the filter, am i right? is there an easier/better way to do this other than getting a HUUUUGE-ass fan and filter combo?
I mean, the room is 2560 cubic feet (or 75 cubic meters) (well it's a rough estimate anyways) but the thing is, replacing the air every 2 minutes would mean a filter with a capacity of 1280 CFM and a fan with a capacity of 1500-1600 cfm (i've added 20 % bc the filter makes it lose power).

Does this look/sound right to you? Or am i making some kind of mistake here?

Thanks in advance guys and i'll keep you posted!

growers use 3 to 1. but in the other direction. it needs to clean the rooms air every 3 minutes. not 3x a minute...

so for your room 2560/3 is 854cfm fan..

you are looking for a HO 8" inline. It will sound like a jet and even with a muffler on both sides it will be an annoying drone.

I suggest bong hits and a splooge. Just like we did in college and kids have been doing in their bedrooms for years. a splooge is a paper towel cardboard stuffed with dryer sheets.
pack a one hitter bong hit. clear the tube. exhale through the splooge. you are safe.

no joints for you.!!

oh also they sell smoke removers for resturaunts and bars. it removes all the smell and smoke. I think they cost a fortune and probably require some special venting etc.

also, also. your filter should lower you fans CFM if you spec it properly. at least thats what the advertising says. If you get a fan rated at 800 and a filter rated at 800 or 850 you should get the fans max output. at least with phresh filters. the chinese ones who knows.

Hi Just a thought instead of buying a fan filter and ducting, invest your money in a quality vapouriser such as a Volcano or an Arizer Extreme these do not give off a smell but give you the desired effect and can be easily hidden unlike a fan and filter should your landlord call.

thank you all for replying guys! @Dr. Strangegrow: does a vape really not give off smell? i mean, i always thought that vapourizers made less of a smell, but a strong smell nonetheless?

@ilikecheetoes: that much noise huh? i hadnt really considered that untill now.. do you have a rough (gu)estimate of how much dB a fan like that would produce?

Also, i really like smoking joints, as opposed to taking one hitters etc. so the filter is definitely my preferred way to go.. i was wondering, and i'm aware that this might be a dumb question but, would it be possible to incorporate a fan like this [link] http://www.conrad.nl/ce/nl/product/...lventilator-HT-112E-30-cm-40-W-2100-mhHT-112E [/Link] in the setup? it's got a 2100 m3/h airflow. (1239 CFM if i'm correct) Would this work? Assuming that i'd be able to connect it air-tight to a filter ofcourse. (which i probably will, seeing as that i'm a pretty handy guy)

If your landlord and neighbours are such hard arse's that they'll throw you out for the slightest hint of an aroma of a joint.... How will they feel about you having loud and expensive looking extractor fans hanging from your living room ceiling...?

The Dutch seem to enjoy large windows in their buildings. If you were to open one of these windows and smoke near it (usually performed whilst sitting on a chair or stool) this may be as much odour control as you need.

In England we're light years behind the civilised world when it comes to the legal status of cannabis but if a neighbour of mine starting complaining about what I did in the privacy of my own home they'd get told to 'Fuck off'.

I've been to Holland many times so I know that cannabis is available everywhere (I've even seen people smoking crack in the street!)
So I doubt that the Dutch SAS will absail from your roof and come smashing through your windows to try and catch a few people smoking a widely available substance....

Air freshener may help
Or Joss sticks

SmokerfromHolland said:

thank you all for replying guys! @Dr. Strangegrow: does a vape really not give off smell? i mean, i always thought that vapourizers made less of a smell, but a strong smell nonetheless?

@ilikecheetoes: that much noise huh? i hadnt really considered that untill now.. do you have a rough (gu)estimate of how much dB a fan like that would produce?

Also, i really like smoking joints, as opposed to taking one hitters etc. so the filter is definitely my preferred way to go.. i was wondering, and i'm aware that this might be a dumb question but, would it be possible to incorporate a fan like this [link] http://www.conrad.nl/ce/nl/product/...lventilator-HT-112E-30-cm-40-W-2100-mhHT-112E [/Link] in the setup? it's got a 2100 m3/h airflow. (1239 CFM if i'm correct) Would this work? Assuming that i'd be able to connect it air-tight to a filter ofcourse. (which i probably will, seeing as that i'm a pretty handy guy)

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Mine doesn't produce a noticeable smell that's using grass, read the reviews on the internet and bought one on the strength of reports of no smell, I just fill the bowl and smoke it like using a Hookah got some bags with it but never tried them. Good luck on whatever you decide

no idea on DB but you wouldnt want to sit around it for long. id guess its in the 80-90db range. its at an annoying range though. theres a drone that gets in your brain and makes you want to jump out the window lol.
the fan you link doesnt have the balls to push through a filter. You need an inline fan. its like torque vs horsepower. yours has horsepower but you need torque to get through a filter.

the vapes with a full dome and a hose you inhale through make no smell until you exhale. so youll still need a splouge.