Intake from attic?

[gembob]

So I currently have a 600watt light in a small room (approx 5x6x8) with a a 400 CFM fan and dont have a separate air intake aside from the bottom gap between the door and the floor (hydroshop employees recommendation) and temps have been fine up until recently. But now with summer coming and temps getting higher the room temps are getting higher and I think the lack of adequate fresh air coming in is a large factor? I've cracked the door and positioned a fan to blow air in the room but for sercurity reasons this can only be a temporary fix. For the same security reasons, the only real place I can have an intake from is the attic (where I'm exhausting the air to now). I can keep the intake and exhaust apart, but I know the attic is still not the optimal place to get fresh air from. My question is this: how much difference will it make having fresh air but having it come from probably the warmest room in the house? I dont want to get up there and cut in an air intake only to find out that the temps don't change. What about adding a swamp cooler? I'm in a very dry climate so don't think humidity would be a problem

 

[fadahigh]

why not INtake from OUTside. hot air rises to the attic + your exhaust + the radient heat of the sun

 

[Lazyman]

Attic intake would be a bad idea, too hot.

I'd suggest cutting a hole in the floor and putting in a fake register vent as a passive intake, and put a powered exhaust (through a carbon filter) up through another one in the ceiling. That way they won't look suspicious when you move out, just a couple unused vents is all.

 

[gembob]

I could get the intake from outside, but because of the security reasons mentioned previously it would have to be from ducting installed through the attic to the outside.

I've never done anything through the floor, would the hole and the register be all I need for the passive intake? Would I have to put duct anywhere or would it just suck air from between the floor boards?

Any opinions on a portable evaporative cooler? Thanks for the advice so far

 

[mjr99]

Maybe cut the door so you have a bigger opening between door and floor? Also try and get a fan blowing right underneath your bulb/glass. I use one of those stanley blower mods on the lowest setting to circulate the air in my room. Put ducting on the end and place the outtake right below your hood. You wouldnt believe the difference.

Not sure about the swamp coolers. If youre in the southwest though... theyre so cheap it couldnt hurt to try.

 

[CANNATOPIA]

do you have roof Vents leading to the outside from the Top or side of roof

 

[CANNATOPIA]

Would be prob be much cooler air VS the attic.

 

[Lazyman]

I could get the intake from outside, but because of the security reasons mentioned previously it would have to be from ducting installed through the attic to the outside.

I've never done anything through the floor, would the hole and the register be all I need for the passive intake? Would I have to put duct anywhere or would it just suck air from between the floor boards?

Any opinions on a portable evaporative cooler? Thanks for the advice so far

Most houses have a crawlspace under them, so that's where the cold air would draw from. If you're on a concrete slab or in an apartment this advice is null and void and you MUST get an air conditioner.

Swamp coolers (evap coolers) are terrible for grows, they increase the humidity way too much and you'll get bud rot, powdery mildew, etc etc. If you live in a desert they MIGHT work but I wouldn't risk it personally.

If your room has a window you can use that too:

Tint the window with mirror film
Make sure you've got an even surface all the way around the window frame for a board to screw to
Lay down some adhesive foam tape 1/2" X1/2" thick in a ring all the way around the window frame where a board would touch it (like a gasket)
Cut a piece of 3/4 inch thick plywood a little bigger than your foam gasket
Paint the outside of the plywood white
If using a fan or AC, cut a hole in the plywood for the duct collar or AC unit to slip through
Screw the board to the wall, lots of screws all the way around
Open the window to allow air out
Slide AC into hole or connect your fan/ducting to hole (or both)

And you're done

 

[PharmaCan]

Attic intake would be a bad idea, too hot.

I'd suggest cutting a hole in the floor and putting in a fake register vent as a passive intake, and put a powered exhaust (through a carbon filter) up through another one in the ceiling. That way they won't look suspicious when you move out, just a couple unused vents is all.

This is probably your best bet. Just make sure you don't cut through a floor joist.

PC

 

[gembob]

Appreciate the advice so far, wanted to provide some info that I didn't mention his far: grow room is on 2nd level, above garage. I'm currently exhausting through open end of reflector then through fan then carbon filter (filter in attic). I guess where I am is considered the desert, frequently have readings of 0% RH and I do have a circ fan aimed between the bulb and plants. Going to check for existing vents to he outdoors and look over the floor option tonite. Don't know how comfortable I am cutting into the floor, I have no experience doing this. What about tapping into an existing ac run and routing directly into the room? Thanks again for all advice so far

 

[Lazyman]

Appreciate the advice so far, wanted to provide some info that I didn't mention his far: grow room is on 2nd level, above garage. I'm currently exhausting through open end of reflector then through fan then carbon filter (filter in attic). I guess where I am is considered the desert, frequently have readings of 0% RH and I do have a circ fan aimed between the bulb and plants. Going to check for existing vents to he outdoors and look over the floor option tonite. Don't know how comfortable I am cutting into the floor, I have no experience doing this. What about tapping into an existing ac run and routing directly into the room? Thanks again for all advice so far

Ok a couple changes I can suggest:

Fans are much more efficient at pushing than pulling. Reroute your air so it goes:

Filter>Fan>duct>hood>outside

Now for cooling the room that's a different story. 0%RH means a swamp cooler COULD work for you, but how effective it is and how much it raises your humidity are another thing. If you already have one or can get one cheap of CL then I'd give it a shot, since you need more RH anyway.

I assume you're running your lights at night so you don't have to fight the heat during the day.

I'd look at adding a vent through the roof you can connect some 6-8" ducting to, then use that as room exhaust and you can use a passive intake. Heat naturally travels upwards, don't try to fight that, but go with it. Draw cooler air in from your garage (if that applies, if not you need AC anyway.)

A split air conditioner would be the best solution but they are kinda pricey. A 1-ton mini split will cool about 3KW pretty well, 4KW if you're air-cooling your hoods.

 

[gembob]

Ok thanks a lot for the help, I'm gonna reconfigure the exhaust and get in the attic to see what my options are up there for venting and maybe try a cheap swamp cooler or ac unit if all else fails. Reistically what is the max temp I should be comfortable with? Is 80 too hot?

 

[Sloppy Seconds]

I dont know if its been mentioned but do you have a cooling hood for your light? A cooltube or something? good luck.

 

[Lazyman]

No 80 is not too hot, as long as you can keep them watered. They will transpire more and need watering more often, which usually means lower nute concentrations (if you're watering with nutes.) Good luck!

 

[SupraSPL]

If you run your light from 9PM to 9Am or something along those lines, you would have a better chance of getting away with intake air from the attic. If there are air intakes on your eaves and vents in the top of the roof, you could more easily draw cool night air from the eave openings.

I switched from inside-house air to nighttime attic-eave air and it made a huge difference. Good luck!