Loft Grow Heat Issue Pls Help

  • Thread starter Treebeard88
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Treebeard88

Treebeard88

23
3
Evening all
My first in door grow in the loft is happening as we speak
I will run into heat issues soon I think, at moment plants seem ok apart from I messed up on 1 tank nute wise but now seems ok
Peak heat has hit 32c & it is only May. In July/August I imagine this will increase
I have used a lot of insulation & the room is pretty much sealed but not 100% but the issue seems to happen when lights are on, when off not so much a problem at all
@ 09:27 out side was 13.6C - inside room was 29.1C and light had been on for 3 hours. If I open door this issue goes but ideally I don't want to do this
I am using a 1000W LED
RVK 100 A1 intake - 184 m3/h
RVK 125 L1 outtake - 323 m3/h
I think the only way round this is to increase the power of the intake + outtake - as outside @ 09:27 was 13.5c, surely bigger fans would work?
After doing some research apparently an outtake of 1756 m3/h & intake of 1473m3/h would be plenty and I would buy a speed controller so in winter I would turn the power down as this issue wouldn't happen. The room size is approx 2230 x 3440 x 2010 & that is being generous - are those m3/h readings way to high?
Any advise would help an in door newbie
AC is a no no - heard portable are crap & not investing in split unit for the loft lol
Treebeard
 
Last edited:
Treebeard88

Treebeard88

23
3
Run your lights at night during summer!
Current schedule

Lights come on at 18:00 and switch off at 12:00
In flower I'll schedule on at 18:00 and off at 06:00

What do you think about the intake/outtake fan power upgrade? That would bring in cooler air from outside faster and take warm air out faster theoretically.

Treeebeard
 
Mostlymooses

Mostlymooses

312
93
I couldn't answer that part, you seem like you have a better understanding of the mechanics of ventilation than I do. Your timing sounds solid, running your flower at night is an easy cheap solution. Upgrading your cooling eventually is probably a good idea.
 
boo

boo

154
63
be sure to put a screen on your intake, pests find ways into your grow, make it hard for them...
 
Ponky

Ponky

3,941
263
If you can seal it 100% you can use CO2. Then your high temperatures won't be an issue. Or just run some duct fans. Have the intakes drawing from the coolest part of the house.
 
Treebeard88

Treebeard88

23
3
If you can seal it 100% you can use CO2. Then your high temperatures won't be an issue. Or just run some duct fans. Have the intakes drawing from the coolest part of the house.
Can't seal 100% unfortunately, that was the original plan
Intake is coming from outside
Thinking of more powerful intake and exhaust to bring in more cooler air and vent the hot air faster
Treebeard
 
Treebeard88

Treebeard88

23
3
Toss in an extra 8" vivosun duct fan. Cheap. Pretty quiet. Mines been on straight for like 4 years.
Will look into this, this is for extraction/outtake?
Would you upgrade intake as well?
My original calculations are off on first post I will edit tomorrow with the correct CFM/m3h
Treebeard
 
Ponky

Ponky

3,941
263
Will look into this, this is for extraction/outtake?
Would you upgrade intake as well?
My original calculations are off on first post I will edit tomorrow with the correct CFM/m3h
Treebeard
Well I'd set one up as an an exhaust. With my air intakes taking cool air from the basement through a filter. And add more exhaust fans and intake pipes if you need to. If the grow space has positive pressure moisture and odor leak out. So I prefer all my fans setup for negative pressure. Except when the fan is cooling the bulbs in an air cooled hood. Then I want my duct fan blowing cool air through the lights.
 
Ponky

Ponky

3,941
263
Will look into this, this is for extraction/outtake?
Would you upgrade intake as well?
My original calculations are off on first post I will edit tomorrow with the correct CFM/m3h
Treebeard
VIVOSUN 8 Inch Inline Duct Fan, 740 CFM Ventilation Fan with Variable Speed Controller for Grow Tent, Indoor Garden Ventilation, Black https://www.amazon.ca/dp/B01CTM0LLO/ref=cm_sw_r_awdo_W77J0N2P58MGAS48BGGR

I like these. Reliable. Affordable. Reasonable sound levels. Can also be had with a charcoal canister in a combo for a good price. And they're a sponsor here on the forum I believe. I'm pretty sure they can give you a coupon code. One moves a lot of air.
 
Anthem

Anthem

4,155
263
Evening all
My first in door grow in the loft is happening as we speak
I will run into heat issues soon I think, at moment plants seem ok apart from I messed up on 1 tank nute wise but now seems ok
Peak heat has hit 32c & it is only May. In July/August I imagine this will increase
I have used a lot of insulation & the room is pretty much sealed but not 100% but the issue seems to happen when lights are on, when off not so much a problem at all
@ 09:27 out side was 13.6C - inside room was 29.1C and light had been on for 3 hours. If I open door this issue goes but ideally I don't want to do this
I am using a 1000W LED
RVK 100 A1 intake - 184 m3/h
RVK 125 L1 outtake - 323 m3/h
I think the only way round this is to increase the power of the intake + outtake - as outside @ 09:27 was 13.5c, surely bigger fans would work?
After doing some research apparently an outtake of 1756 m3/h & intake of 1473m3/h would be plenty and I would buy a speed controller so in winter I would turn the power down as this issue wouldn't happen. The room size is approx 2230 x 3440 x 2010 & that is being generous - are those m3/h readings way to high?
Any advise would help an in door newbie
AC is a no no - heard portable are crap & not investing in split unit for the loft lol
Treebeard
Believe it or not you are making the problem worse by adding insulation. The heat is coming form the lights and with additional insulation it cannot transfer thru the walls and ceiling as easily. Myself I prefer a passive intake, ideally from outside air and forces ducted exhaust. The problem you are having is partly due to the insulation you have added because it works both ways.
 

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