Extractor fan.....Do i need an intake fan as well?

Hi folks

Just as the title says, do I need an intake fan?

I've got a 1.2m X 1.2m X 2.0m grow tent running a 600w HPS dual specturm bulb (no air cooled hood) and a 5" carbon filter and a 5" inline duct extractor fan hanging by rope ratchets in the tent.
According to the fan and filter specs pulled by the manufacturers website the fan and filter is capable of cleaning 400m3/hr of humid air inside but I'm not sure whether those are accurate figures as testing the tent is running temps of 40°C!!!!

I was thinking of purchasing a small intake fan and installing it onto my intake vent opposite side of the extractor to pull in fresh air but I'm not sure what size I'd need.

I've got some small cip on fans for inside the tent for good air circulation but haven't installed these yet. Do these fans make a difference in lowering temps or is it just blowing hot air and I really need an intake fan?

Any advice you can give would be great!!!
Has anyone completed a grow with this type of set-up?
 

coreywebster

Well-Known Member
So circulation fans don't themselves lower the actual air temp but they do mix the air and without them you can have hotter areas and the plants themselves will have a microclimate around their leaves which is warmer than the rest of the space , adding the fans will help the plant keep cooler that way. Same as it does for humans. It helps remove a thin film of warmer air around our skin which helps us sweat the same as a plant transpires.


As for the temp issues here are a few rules that are important for most situations.

1. make sure you vent out of the room, preferably out of the house or you may be just recycling the same warm air.
2. Don't have your thermometer in direct light , they are effected by light and the unit will heat up from IR light and give false readings of air temp.
3. Fan size or air exchange calculators are vague and don't take into account your actual climate, a 5" may be enough for one guy but another guy may need an 8"
4. Providing your not recycling your air an air cooled hood is the cheapest way to remove the heat.
5. If your air coming in (ambient air) is already warmer than what you want your temps in tent to be then no amount of air exchange is going to help and AC is required.
6. Open all bottom vents and close all vent socks up high.
7. Intakes only really help when your extracting so much air that passive intake cant keep up. In most cases a 4x4 tent should not need an intake.
The money would be better spent on air cooling your light or increasing extraction. An exception to that would be when you cant have your vent flaps open because you don't want light illuminating the room, an intake will be useful in that situation.

If you give us a clue on your ambient air temps and post a pic of your set up and tell us what exact fan you have , because not all fans are good at the job they are sold for, then we might be able to suggest more.
While your at it tell us where your hot air goes and where your new air comes from.

:peace:
 
Last edited:

KK26

Well-Known Member
I have the same set up, size, 600HPS and same size extraction but you must have intake in my opinion.

I have 1 x 4" RAM toned down fan intake bringing fresh air in from the outside. Filtered of course to stop bugs and what not.

Remember, always extract into a different room/place because as @coreywebster correctly pointed out, you'll be recirculating the useless hot extracted air over and over.

Also worth remembering that the built in vents on the bottom of your tent are your friend and there is intake right there
 
Thanks for the great advice mate.

1. I have it properly vented out the window now, before the hose was just near the window as the room overlooks a housing estate car park and I was worried about someone spotting it. Now I've wrapped the end of the ducting in white pvc tape and installed a dryer duct box. This allows me to properly vent it out the window and hopefully still remain stealthy.
2. The fan and filter was part of the bundle I bought online. It's a 5" Kaizen Inline duct extraction fan and a 5" Kaizen carbon filter. This is how I've got it set up:
20200811_120232.jpg
The ducting goes out the top of the tent and out the window. The exhaust hole on top of the tent is a bit away from the window so it's not straight out from the top which I know can affect how much air it pulls but I've at least managed to get it outside.
3. My flat averages about 22°C. I've got a thermostat so I never let it get too cold.
I've got 2 x 9" desk fans that I'm gonna install above and below which should help at least with air circulation inside.

Definitely going to buy an air cooled hood. 20200811_120329.jpg
It's only a Euro reflector which I have used before but I had it in a loft at the time so managed to vent it straight out the roof.
 
I'm a bit worried about the airflow in the room though especially if the door is closed so was looking at an intake fan.
I've managed to spot this one on eBay. Does this look ok?
Screenshot_20200811-122840_Chrome.jpg
Cant really let a lot of light out into the room so cant open all my intakes all the time.
 

coreywebster

Well-Known Member
I would avoid that fan as an intake, it looks like a kenley just different brand. Try looking for a second hand rvk, ruck or similar which you should be able to pick up for around same price.
It basically wants to look like your extractor , the impellors on those fans you just linked just don't cope well with anything. I don't really understand why they even make them to be honest.

Even a room with a closed door will allow plenty of passive air exchange unless someone has mistakenly sealed under skirtings ect which shouldn't be done but some people do it, mostly carpet fitters.
But lifting a floor board will usually increase the amount of air that can come in since mostly joists are not sealed air tight from room to room.

All my rooms have always been closed off, light proofed so never needed intakes and didnt have to worry about light from vents.
End of the day heat waves going on all over the place at the moe and it does spike the temps to above comfortable where it might be otherwise ok 90% of the year.

Air cooled hood is a must for you. Just take your time when choosing, ive had some medium priced ones not fit for purpose without a lot of fuckery and ive had some cheap ones made very well and sealed.
I actually like the newer cooltube xl hoods because they offer the good points of a cool tube, been smooth and little air resistance without the negative of the old terrible reflector and shit foot print. But with a single light any well made well sealed hood will be a massive benefit.

I don't use any hoods these days since I don't use HID anymore.
 

PissingNutes

Active Member
First off on this site you will get trolled if you didn't buy LEDs from the usual suspects or using the better nutes. :roll:
Using proper lights wether LED or HPS means you need an AC. Everyones grow area is different and you will learn how it 'breathes'.
Your filter can be lowered from ceiling closer to optimal spot to pull heat and I find the air fresher and cooler when blowing air in as well .
Eventuallly you will find the right spot for your equipment you choose but hygrometers tell you what's going on in your area.
 

KK26

Well-Known Member
I'm a bit worried about the airflow in the room though especially if the door is closed so was looking at an intake fan.
I've managed to spot this one on eBay. Does this look ok?
View attachment 4650240
Cant really let a lot of light out into the room so cant open all my intakes all the time.
When I said RAM I meant this one

It's available in most sizes and is good for me, had them over 3 years working full time and never failed.

Screenshot_20200811_135151_com.brave.browser.jpg
 
First off on this site you will get trolled if you didn't buy LEDs from the usual suspects or using the better nutes. :roll:
Using proper lights wether LED or HPS means you need an AC. Everyones grow area is different and you will learn how it 'breathes'.
Your filter can be lowered from ceiling closer to optimal spot to pull heat and I find the air fresher and cooler when blowing air in as well .
Eventuallly you will find the right spot for your equipment you choose but hygrometers tell you what's going on in your area.
I keep coming back to getting an a/c mate.

I've tried to see if I can exchange parts of the bundle but I've had no reply from the company I bought it from so guess I'm stuck with my set up as is. When I had it set up and running before its seemed fine....side of the tents would suck in but I hadn't really vented it fully out the window so the room was high temps all the time. An ac is probably the only option I've got right now, already sunk enough cash into it without a brand new set up whether that be LED or passive intake.

Honestly mate cheers for the advice, I know I've been a pain in the arse!!
 
I have the same set up, size, 600HPS and same size extraction but you must have intake in my opinion.

I have 1 x 4" RAM toned down fan intake bringing fresh air in from the outside. Filtered of course to stop bugs and what not.

Remember, always extract into a different room/place because as @coreywebster correctly pointed out, you'll be recirculating the useless hot extracted air over and over.

Also worth remembering that the built in vents on the bottom of your tent are your friend and there is intake right there
Thanks for the advice mate. All appreciated!!!

I've managed to get the hose fully out the window now, that was causing me no ends of grief before as it was only near the window so extraction is cool now hopefully.

Think I'm gonna go with getting an ac though. Theres only one window in my room and I'm not really want to put two hoses out the window, seems a bit suss to others, especially as it overlooks the buildings carpark so everyone can see it.
What kind of bulb are you running? Is it the same bulb for seedlings, veg etc.....

I've only got the dual spectrum bulb and I've never used it on seedlings before so wondering if itll be too much for young seedlings?
 

PissingNutes

Active Member
I've only got the dual spectrum bulb and I've never used it on seedlings before so wondering if itll be too much for young seedlings?
You'll find the sweetspots. To buy LED's that come remotely close to 600w HPS cost over five times the price. Can buy and run HPS for three years. Either way you need [roper environment is key, you have better than average lights and all succesful grows need the other controls.
 

PissingNutes

Active Member
The way I see it it's an investment that gives you return in plant weight. My first setup cost about 2000$ to put together for 2-3 plants rotation at a time and after 4 months and two grows I totalled 10 ounces on fast autos because my envorinment is getting dialed in. Growers can grow on low watt good spectrum lighting but the weight of those plants can be hugely increased...
 

KK26

Well-Known Member
Thanks for the advice mate. All appreciated!!!

I've managed to get the hose fully out the window now, that was causing me no ends of grief before as it was only near the window so extraction is cool now hopefully.

Think I'm gonna go with getting an ac though. Theres only one window in my room and I'm not really want to put two hoses out the window, seems a bit suss to others, especially as it overlooks the buildings carpark so everyone can see it.
What kind of bulb are you running? Is it the same bulb for seedlings, veg etc.....

I've only got the dual spectrum bulb and I've never used it on seedlings before so wondering if itll be too much for young seedlings?
Bearing in mind I'm in the UK my setup works for me but that is not to say it works for all.

I use 600WATT HPS throughout the year on all plants, seedling too, just keep the distance and you can get them to grow out well. HPS is trusty, proven and I like it because it works for me.

In UK winters can be cold and my HPS is my heat source and in summer it's the opposite but this is where the good extraction and intake works well for me. Even in the height if summer my space will not go over 30 at the very most. With my fresh air ntakes, the circulation fans in the space and basic control over my extraction I have fair environment with plenty of clear air exchanges which works in summer.

In winter the opposite, longer veg sometimes when a cold ass and lazy keeping light on more for heat but when off, I grow on a pallet and attached on the underside with the cavity I have 3 tube heaters which always keep the pots/roots a lot warmer than everywhere else and I have been happy/lucky.

I'm not new and have grown decades but what I have learned is that there us no sset in stone grow bible and what works for some may not work for others.

For me I know what works and what don't and sorry but I can offer no more really. Makes it hard because of location obviously and an AC might be your best option but I am not familiar with them in the grow room so I'll have to bow out and leave you with the experts.

Hope you get it sorted
 

PissingNutes

Active Member
Everyones grow area is different and you will learn how it 'breathes'.
...I find the air fresher and cooler when blowing air in as well .
Just to be clear my setup doesn't have an intake from outside just an exhaust and I cool the room the tent is in then add or remove humidity at the tent. About the seedlings, they need some consistency in light so start on something close to what they will finish on but lower light will keep them from bushing too much...in my experience the plant will likely suffer from other environment factors before light burn.
 

NukaKola

Well-Known Member
Thanks for the advice mate. All appreciated!!!

I've managed to get the hose fully out the window now, that was causing me no ends of grief before as it was only near the window so extraction is cool now hopefully.

Think I'm gonna go with getting an ac though. Theres only one window in my room and I'm not really want to put two hoses out the window, seems a bit suss to others, especially as it overlooks the buildings carpark so everyone can see it.
What kind of bulb are you running? Is it the same bulb for seedlings, veg etc.....

I've only got the dual spectrum bulb and I've never used it on seedlings before so wondering if itll be too much for young seedlings?
You're fine having two ducts going to a window if you want to add an intake fan, people will just assume you have a portable air conditioner.

Just get an air-cooled hood and run a piece of ducting to it either after your carbon filter or after the exhaust fan. Something like this.

IMG-3892.jpg
 
Last edited:

jondamon

Well-Known Member
First off on this site you will get trolled if you didn't buy LEDs from the usual suspects or using the better nutes. :roll:
Using proper lights wether LED or HPS means you need an AC. Everyones grow area is different and you will learn how it 'breathes'.
Your filter can be lowered from ceiling closer to optimal spot to pull heat and I find the air fresher and cooler when blowing air in as well .
Eventuallly you will find the right spot for your equipment you choose but hygrometers tell you what's going on in your area.
Not trying to sound like a dick here but OP linked an advert to a U.K. fan for £30.

anyone in the U.K. doing a personal grow with 2 lights of less doesn’t need AC.

Electricity costs in the U.K. are sky high and as such will cost 1.5x more for the AC to run per hour than his light.

I reiterate if you grow in the U.K. and use less than 2 lights you WONT NEED AC.

@coreywebster will see you right on the correct fans etc.

you just need to realistic about grow positions and equipment choices.

a 1.2m2 tent for a 600w will struggle to keep
Temps down during summer without an air cooled reflector.
 

PissingNutes

Active Member
Not trying to sound like a dick here but OP linked an advert to a U.K. fan for £30.

anyone in the U.K. doing a personal grow with 2 lights of less doesn’t need AC.

Electricity costs in the U.K. are sky high and as such will cost 1.5x more for the AC to run per hour than his light.

I reiterate if you grow in the U.K. and use less than 2 lights you WONT NEED AC.

@coreywebster will see you right on the correct fans etc.

you just need to realistic about grow positions and equipment choices.

a 1.2m2 tent for a 600w will struggle to keep
Temps down during summer without an air cooled reflector.
what? Thanks for proving my point, op posted about how to work with his 600w light. So gave my feedback thanks.
 
Hi guys.

Honestly cheers for all the advice and knowledge of your set ups. All I seem to have done past few days is research, test and troubleshoot and watch bloody YouTube videos!!! Lol.

Reiterate a little more here, yes I am in the UK as @jondamon points out and no you didn't sound like a dick mate! All input is good input!!

Final set up (hopefully)
I agonized over what to do with regards to an a/c or an air cooled hood as can only afford one just now and I think an air cooled hood is the best way forward. Checking air-cons online last night and even the expensive are pretty loud, the quietest I can find is 65db which is as loud as a Hoover running!!

Decided on purchasing an air-cooled hood instead.... @coreywebster what's your opinion on this?
Screenshot_20200812-115750_eBay.jpg

If that's ok then I'm going to buy it tomorrow, will take a few days to arrive but I'm sure I'll find something else to sort.

Honestly folks cheers for the direction and all your opinions.
 

jondamon

Well-Known Member
Hi guys.

Honestly cheers for all the advice and knowledge of your set ups. All I seem to have done past few days is research, test and troubleshoot and watch bloody YouTube videos!!! Lol.

Reiterate a little more here, yes I am in the UK as @jondamon points out and no you didn't sound like a dick mate! All input is good input!!

Final set up (hopefully)
I agonized over what to do with regards to an a/c or an air cooled hood as can only afford one just now and I think an air cooled hood is the best way forward. Checking air-cons online last night and even the expensive are pretty loud, the quietest I can find is 65db which is as loud as a Hoover running!!

Decided on purchasing an air-cooled hood instead.... @coreywebster what's your opinion on this?
View attachment 4651190

If that's ok then I'm going to buy it tomorrow, will take a few days to arrive but I'm sure I'll find something else to sort.

Honestly folks cheers for the direction and all your opinions.
Looks pretty good.

when I was working with the same size light (600w) I utilised a SUNSYSTEMS BLOCKBUSTER XXL cost me £175 lol.

Now I work with the same size room I did before 7x3.2x8 only I use a 400w open reflector which with one fan and 3 passive intakes works perfectly for me.

400w digital ballast
400w MH lamp (veg)
400w HPS lamp (flower)
Adjust a wing reflector (medium)
200w CFL (seedling and early veg)
460m3/h RVK150A1 fan
SMS Fam speed controller
rhino pro 900m3/h filter
80w tubular Heater
RAM humidifier
Dehumidifier
Oscilating fans

Here’s some pics of my last grow utilising 400w.

Just make sure you exhaust away from the room with your grow in it.

no need to recirculate already warm air.

cold air in
Warm air out of area.

basically meaning don’t Dump all your warm air into the room with the tent in it.
Get it away to another room or out of the house. 68528286-FFF0-4597-9B78-F53D3E35879A.jpegEB9FAD12-99D7-45AB-82A9-6FF3906B05EB.jpeg482C4F54-20F6-4000-A159-41CACFCACB9D.jpeg730B46CD-9308-4A4D-85CA-35F63A9D2076.jpegB091DA2B-90D0-4799-B4ED-98E06B0CFCAF.jpegED5D3477-6A53-4A16-83A5-AE294BCD66E0.jpeg59E43E9F-7BE3-4804-A89A-78540FAA58A4.jpeg
 

KK26

Well-Known Member
Not trying to sound like a dick here but OP linked an advert to a U.K. fan for £30.

anyone in the U.K. doing a personal grow with 2 lights of less doesn’t need AC.

Electricity costs in the U.K. are sky high and as such will cost 1.5x more for the AC to run per hour than his light.

I reiterate if you grow in the U.K. and use less than 2 lights you WONT NEED AC.

@coreywebster will see you right on the correct fans etc.

you just need to realistic about grow positions and equipment choices.

a 1.2m2 tent for a 600w will struggle to keep
Temps down during summer without an air cooled reflector.

Ah the OP is in the UK!

WTF All the talk of ACs. Nah, cross AC off right way and only 2 plants.

@jondamon is right but I do fairly well with a 600watt during summer without an air cooled hood. I use a Parabolic Reflector, the Maxibright one which has decent vents and open exposure on the top of hood and around the bulb placement area.

I really think the Parabolic design helps a lot with heat distribution provides perfect coverageafor my 1.2m2. This alone with good intake and extraction keeps me below 30 even on the hottest of summer days.

Just to be clear also, I do have it lucky whereas the outhouse in which I grow is always shaded and that helps when hot summer days but in winter that outhouse gets fucking stone cold.

AAnyways, I dipped out of this thread because AC was mentioned and I just guessed the OP was in the US. You'll get sorted here @SweatingBuckets with these lads from the UK who have posted.
 
>
Top