ok i have about 450 cu ft of grow room. maybe 10% of that is filled up with stuff so i have an air volume of maybe 400cu ft. lets pretend the room is absolutely air tight. and lets pretend that the extractor fan that im gonna put in does a full air exchange in 1 minute worth of running. and lets pretend that i would like this to be running as little as possible because of stealth. i know that it depends on how much plant material im growing and how leaky the room is but... if i had a timer set for a fan to turn on and off, im wondering how many times a day? my innitial idea is 1 every 2 hrs of HPS 12/12 and 2 times during the night.
Froggy, I'm sorry I don't know the answer to your question, but I had a couple for you. Would it be alright if I sent you a pm about some more "complicated breeding questions"? If not it's cool, I just didn't want to pm you to ask if I could pm you lol .
the size of room and speed of fan isnt whats important. what is important is speed of build up of heat and/or use of co2 like you pointed to. oh and smell aswell probably. now im in the same boat as you at the moment and looking to vent a grow tent as quiet as posable.... after much reading up and long talks with my friendly fan salesman (also a grower) to use the fan i have its going to take a speed control of some sort and the fan to be run most, if not all of the time rather than stop/start. the reason being that a fan makes the most noise when starting up. a constant runing fan that is speed limited, acoustic ducting etc will at the most make a low hum that i hope will not carry. but having a fan hard start at regular times of the day and night is going to be more noticable to people, where as i hope the low hum wil be lost in the noise of the city. or use a tempcontrol to start the fan, at least that way the start times wont be regular and it'll take most of the guess work out of te timeing, just have to deside what temp to set the control at.
i got access to a super quiet fan. and the outside looks like a bathroom fan exaust. it really doesnt have a much of a sound, more of a vibration than anything. its pretty stealth. im not worried about heat build up at all. never reaches 90F in my room. im worried about the smell inside the house. im also worried about the smell outside the house. that is why im thinking of short bursts of exchange for my situation is better. i also dont wanna keep it going 24/7 because that will be a huge waste of heating and it will keep my room even colder in the winter (that is when i do my indoor growing). more than anything tho, i wanna make sure that im getting good air circulation and proper exchanges. i also have the room that is fairly air tight, with one crack that is lightproof. i can imagine that 4-6 exchanges a day will be MORE than fine but really i dont know for sure. that is why the q
well, if ya want to be extremly high tech about it buy a CO2 monitor and hook your fan up to it, so the sair changed out every time the CO2 levels drop below the set limits.... or have it hooked up to both a CO2 monitor and temperature gauge... so if it either drops below set CO2 levels or goes over say ~70F it turns on the fan.... can always make a big carbon scrubber for smell outside... or if you live in a rather rural area with no close neighbors you dont really need to worry about smell.....
i see your point. to be honest i woudnt like to guess as to how often to vent for the co2 part of it, there are to many things to take into account. as far as smell goes tho id have a fan in the room with the filter on it running all the time. a lot of smell can build up in just 2 hrs and as you know when your around them all the time you just dont smell it till it gets really bad. i know it may sound like over kill but if your asking this question then you must have a good reason, better safe than sorry. remember... (_._) <- your arse (_O_) <- your arse in jail
i love it hippy. that is the answer, exchange on a co2 trigger. and yes im gonna develop an inside filter also. im not all that worried about the outside smell but ur right, better safe than sorry.
http://www.greenair.com/cdmc.htm seems like they hover around the $400 mark.... might find a cheap one on ebay or something.....
I searched and searched and searched and searched, and found one for $279.... and i didnt save the address.... i didnt look on ebay though... i think that'll be your best bet for finding a cheap one....