40oz Posted December 23, 2003 Share Posted December 23, 2003 hi 40oz here, i was jus wonderin wot fan id need 4 a 2x2.5x5 ft wardrobe with a 250 watt hps in it would i need old air taking out or new air taking in, and can i drill holes in my lamp reflector and suck hot air away ? thanx 40oz Link to comment Share on other sites More sharing options...
pd666 Posted December 23, 2003 Share Posted December 23, 2003 lti fan or something like that 4" dogs baws ya ya can drill holes and exstract heat and old air from the reflector or from the room intake u could maybe getaway with a couple o flans blowing air in Link to comment Share on other sites More sharing options...
Spliffy. Posted December 23, 2003 Share Posted December 23, 2003 Check my thread Ventilation There's your answer, ummm I think. Link to comment Share on other sites More sharing options...
40oz Posted December 23, 2003 Author Share Posted December 23, 2003 ive just been to b n q to get some make do fans until i can afford a big extractor, i cut out a hole in the back of my space and it all seemed fine but then i noticed the noise from the fan, i was just wondering when i get my extractor, even if the fan is relativly quite will there be any noise from the end of the ducting as it will just be leading in to my bedroom and not outside and its supposed to a stealth grow. my make do fan is originally a heater but it has a cool blow function that im using, as this fan is abit beefy, would it be alright just to have a pc or thin osscilating fan as my inlet and a big extractor as my outlet thanx 40oz p.s i only have a few cm's between the back of my wardrobe/growroom and my wall Link to comment Share on other sites More sharing options...
40oz Posted December 23, 2003 Author Share Posted December 23, 2003 thanx ppl i realy appriciate the help, so im gonna need a 4 incher and some fans blowin in and hole in the top of my reflector with the sucking end of the extractor over it Link to comment Share on other sites More sharing options...
40oz Posted December 27, 2003 Author Share Posted December 27, 2003 40oz here, just wondering how to work out the cfm of a fan needed for a growroom, the room size is 2.5wx2Lx4.5h feet or 76wx61Lx138h cm ive got a 250 watt hps in there so it would get pretty hot and also does anyone have a decibel rating for any of these fans, thanx 40oz Link to comment Share on other sites More sharing options...
Mind Your Head Posted December 27, 2003 Share Posted December 27, 2003 2.5 X 2 X 4.5 = 22.5 cubic feet Your fan must shift at least that much air every 5mins = 4.5 cfm In almost any practical application any fan will not perform to spec. So double it at least. In fact I would say you want a 20cfm fan at least. Most good 'case' fans will do that. Probably more important is the efficiency of you passive vents. Link to comment Share on other sites More sharing options...
40oz Posted December 27, 2003 Author Share Posted December 27, 2003 cheers mate so does that mean that i wouldnt need a big extractor, because two of these pc fans would shift that amount and theyre stealth ones 20 decibels overclockers 40oz Link to comment Share on other sites More sharing options...
oldtimer1 Posted December 27, 2003 Share Posted December 27, 2003 PC fans are no good at pushing air through ducting, where were you thinking of moveing your Co2 depleated air to?. Ventilation is not about cooling its about getting Co2 laden fresh air to your plants. Cooling is only a side effect of ventilation. Link to comment Share on other sites More sharing options...
Mind Your Head Posted December 27, 2003 Share Posted December 27, 2003 (edited) more important is the efficiency of you passive vents. It all depends on your setup m8. Two of those fans will do the job IF the air flows freely enough through the whole system. It might work better with one blowing in at the bottom and the other sucking out at the top A bit of experimenting might be called for. Use a thermometer and keep an eye on the temps. Better to have more air flow than you need, rather than not enough. [edit] And what ot1 said. Edited December 27, 2003 by Mind Your Head Link to comment Share on other sites More sharing options...
40oz Posted December 27, 2003 Author Share Posted December 27, 2003 i was thinking of venting from the wardrobe into the room and pulling fresh co2 from the same room, its quite a large room. plus open room doors etc. the heat extraction is quite a big deal for me because its a very powerful light in such a small space(250 hps). i only need a fan that is hopefully below 20 decibels and can do 20 cfm any ideas that can also cool the wardrobe down, any ideas ? Link to comment Share on other sites More sharing options...
40oz Posted December 27, 2003 Author Share Posted December 27, 2003 cheers for youre help everyone, more advice welcome 40oz Link to comment Share on other sites More sharing options...
Guest Red Dragon Posted December 28, 2003 Share Posted December 28, 2003 Hi 40oz; I have to say that if you use high quality PC fans that are attached to, (and drawing air through) the skin of the wardrobe, then as long as the airflows unhindered, you are only asking the PC fans to do what they were designed for in the first place. In this instance I would hazard a guess that they would be fine. When asked to pull air through a duct, (be it 1 inch or 1 foot wide), then the majority of fans lose efficiency, and if you ask a fan to pull air through 3 metres of ducting you can lose as much as 80% of the "design CFM" of the fan, which can equate to a massive loss, (not even worth doing unless the fan is a high quality inline Lti jobber). But seeing as you have no ducting involved in venting through the wardrobe skin I reckon 2 PC fans will do just fine. Just remember to make sure the air flow is enough for the fans, (drill lots of little holes), and that any intakes, (passive or otherwise) can provide as much air as the extractor fans require. Of course, odour control then comes in to play. Good luck with the grow. Peace. RD Link to comment Share on other sites More sharing options...
Vlad (the impala) Posted December 28, 2003 Share Posted December 28, 2003 I've actually used some of the overclockers fans - for cooling computers - great, for a growroom - total shite! They're actually horribly noisy, and the amount of air they quote is unrestricted flow - with no filtration (which seems rather daft), they might just stop you catching fire,otherwise- they haven't a hope in hell - you need a pukka axial flow, or mixed flow fan (a far more efficient design, that has a lot of "suck", and can overcome the resistance of a carbon filter) - I reckon you'll need an RVK or similar. By the time you've bought a couple of those overcooked fans, and a speed controller, had vat and postage bunged on top, you'd be better off getting a real fan to start with! People have horribly short memories- only a few months ago, even experienced growers were having massive heat problems - what may (just) work now will be hopelessly inadequate when the temperatures go back up! Link to comment Share on other sites More sharing options...
Guest Red Dragon Posted December 28, 2003 Share Posted December 28, 2003 They're actually horribly noisy, and the amount of air they quote is unrestricted flow - with no filtration (which seems rather daft), they might just stop you catching fire,otherwise- they haven't a hope in hell - you need a pukka axial flow, or mixed flow fan (a far more efficient design, that has a lot of "suck", and can overcome the resistance of a carbon filter) Valid points as always Farmweb, but is that strictly true for a wardrobe? There was no mention of carbon filters in the original post, (or maybe I just missed it ) My PC is a piece of crap and the fan is a rather loud, (around 35Db) whirry thing but even so, I don't hear my PC when it is running in the other room, and I know from personal experience that the custom fans made for PC modders are almost silent in use. The issue regarding heat though, is a valid one, and one which is better sorted out sooner rather than later. A slight redesign methinks? Peace RD Link to comment Share on other sites More sharing options...
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