Advice needed on exhaust fan! :)

Hey guys I'm about to set up my grow tent but i haven't yet purchased my exhaust fan cause im not quite sure what size i need.

I don't think I'll be growing more then one or two plants at a time so my grow tent is rather small
The size is .9m by .5m and 1.6m tall

Im just wondering if a cheap 8" fan that can move 450cfm is over kill or would i be better off with a 6" that can move 250cfm?

My light set up is just a single 130w cfl 6400k for veg and a 130w 3000k for flowering. I am thinking about getting two smaller lamps and having them sitting on the side of the pot to give it a different light spectrum tho. Maybe around 48w bulbs?

Where i live its coming into summer now as well so that's what is stalling my choice on the fan, not sure what would suit my needs best

Any advice fellas?
Thank you

6" inline fan is plenty for that grow tent.

250cm should be fine with cfls. I used a 195cfm for my old tent with a 250w hps and it did ok so you should be fine.

Awesome thanks for that, I'm just abit worried cause summer is coming up around the corner and it'll get hot, a fair few days over 35° and a couple that hit 43° lol
So 250cfm should control temps that go that high?

the most important thing is to get a good match with fan to filter, filters are rated in cfm aswell so if u get a 450 cfm filter you want 450 fan, that way they work efficently and effectivly. rvk fans are really good if there in your price range.

Yea I'll be sure to match up the correct sized filter with the fan once i can decide what to get lol

For my box that is 5' x 4' x 2', a 6" fan I got from Amazon works great. It's $24 shipped. 240 CFM. Comes with a cord and plug.


Duct Fan

does the difference between centrifugal and inline really matter? there is a price difference of about $80, so im wondering if its actually worth it for a very small grow op like my one

http://www.ebay.com.au/itm/6-INLINE-155-WATT-CENTRIFUGAL-EXHAUST-VENT-FAN-BLOWER-/170930375160?pt=AU_Seed_Starting_Hydroponics&hash=item27cc3e89f8&_uhb=1#ht_1724wt_1398

vs

http://www.ebay.com.au/itm/INLINE-VENTILATING-EXHAUST-FAN-6-150MM-25W-METAL-/170931910606?pt=LH_DefaultDomain_15&hash=item27cc55f7ce&_uhb=1#ht_1887wt_1398

i will be getting the carbon filter in the coming weeks when it is required to cover the smell, until then i want to lower the temps alot because its hanging around 30c and %70 humidity here :/

gigathnx said:

does the difference between centrifugal and inline really matter? there is a price difference of about $80, so im wondering if its actually worth it for a very small grow op like my one

http://www.ebay.com.au/itm/6-INLINE-155-WATT-CENTRIFUGAL-EXHAUST-VENT-FAN-BLOWER-/170930375160?pt=AU_Seed_Starting_Hydroponics&hash=item27cc3e89f8&_uhb=1#ht_1724wt_1398

vs

http://www.ebay.com.au/itm/INLINE-VENTILATING-EXHAUST-FAN-6-150MM-25W-METAL-/170931910606?pt=LH_DefaultDomain_15&hash=item27cc55f7ce&_uhb=1#ht_1887wt_1398

i will be getting the carbon filter in the coming weeks when it is required to cover the smell, until then i want to lower the temps alot because its hanging around 30c and %70 humidity here :/

Click to expand...

Yes, the difference ABSOLUTELY matters...you cannot run a carbon filter with the cheaper inline duct fan, you need the centrifugal blower.The first listing is the good one, the second listing is only if you're not gonna place any air flow resistance on it(i.e. carbon filter, several feet of ducting, etc.)

OK purchased the centrifugal fan
Would the inline be good to use to supply air to the tent from a several feet of ducting?

Not gonna knock your purchase, but you can certainly use a filter with the inline fans. I've seen several people do so with no trouble. The extra CFM you get from that fan may come in handy one day though. You may also consider making DYI carbon filters. They'll run you about 10 to make and 5 to recharge. Way cheaper than store bought. There's several thread tutorials on them that I used to make mine. They work great.

And yes, you can use an in-line fan to move air through several feet of ducting. They were originally designed to, and this may come as a shock, move air through several feet of ducting! Crazy, I know. Some people just believe that spending more is a necessity. There's all sorts of marketing/psychological studies that prove this.

I'm sure if you ask someone that bought an $80 fan, they'll say the $25 fan is no good. It's a defense mechanism - it justifies the extra money spent. We're all guilty of it.

Either way i went with more expensive fan cause i figuredthe higher cfm would help lower the temp more, trying to lower it 10degrees more to about 24degrees :/
Its damn hot here!