Temp Management/Possible Upgrade?

So last year I built a grow room in my garage (11X14) which worked out pretty well. However, during summer it
just does not make any sense to battle the heat. NOT cost efficient at all. I have a 20,000 btu window ac that I use for cooling which does a good job until the summer months. When I built this room I used rolls of thermal insulation in my walls.


I was wondering if anyone here has used the spray foam insulation in a similar setup? Was it worth it? I really dont want to throw away 300 bucks or more for something that doesnt help....... Growing has really helped me manage my PTSD and I have no problem with spending the money if it enables me to grow year around. I swear the summer feels like a year when Im waiting on cooler weather ( below 90F).

What kind of lighting are you using? How is your ventilation setup?

Im using LED lighting. A total of 1500 watts from the outlet. I have a 6 inch inline fan exhausting to the attic from a 5x9 tent inside the room. I used the window ac to cool the room and a 8 inch inline (outside the tent) attached to a filter to pull clean cool air into the tent. The 8 inch fan is attached to a environmental controller so it runs only when my temps get to 84F in the tent.

You should have your environment temp controller hooked to the exhaust vent not the intake. Run a passive intake and let the exhaust kick on when the room hits your desired temp maximum (84*F) and it will create a negative pressure in the tent pulling the cool air conditioned air from the room into the tent. Try this and I bet it will be sooo much cooler in your tent with far less work and energy wasted. heres a quick doodle that helps explain what I mean:

Thats how I had it configured initially and it would get hot and very stinky. The intake fan only turns on when the cool air from the negative pressure is just not enough to keep the desired temps. The room is just not holding the cool air from the ac very well which leads me to believe that I have a major air leak problem. Thats why Im asking about the foam. I was thinking if I sealed the edged of the ac and all the edges and creases in the room with the spray foam insulation it would help. What do you think?

I dont understand where the hot air goes when your intake fan kicks on? The temp control should be inside the tent with the exhaust fan plugged into the thermostat. When the themostat hits say 78*F the exhaust fan kicks on pulling the cool air from outside of the tent into the tent while exhausting the filtered hot air outside of the tent into the attic, then the thermostat kicks off once the desired temp is achieved. I cant wrap my head around how you are saying it is hooked up now or how this would be effective or work? If you need an intake fan as an "assist", and your temps are getting too hot -then your exhaust fan is just too small for the job. With the proper exhaust fan, you shouldnt need an intake fan at all and your tent should cave in a bit at the walls when the exhaust kicks on and creates a negative pressure.

The exhaust fan (located inside the tent) runs constantly scrubbing the air and exhausting the hot air into the attic. You are absolutely correct... my tent does suck in when the intake is not running. So much to the point where I put 2x4 along the walls and attached them to the poles to keep the tent walls off of my plants. Are you suggesting that I might me exhausting cool air to fast which is making my ac constantly run?

Got a pic of your setup?

Unfortunately not.....Im out of town! I really appreciate you trying to help me though. When I get back home Ill take some pics and repost. In a hotel trying to wrap my head around a solution so I can start another grow when I get home in May. You know how it is!

Wish I could help

Now that I think about it... I do have a window with a black out curtain. Maybe if I seal the window the 3M plastic kit it would help

No worries... Ill figure it out! This type of thing isn't considered work to me! Im constantly learning!

You are trying to cool the garage and pull that air through the tent I take it. Unless you insulate the shit out of it then if I'm correct it's gonna be a struggle. But yes foam works well.

Im trying to cool the room I built inside the garage and pull that air through the tent. Thanks!

Ok got ya and yes sounds like you need to insulate more. 6" fibreglass batts or foam equivalent would be the minumum for most applications. Also your tent only needs a slight negative so perhaps more passive intake.

Sounds like a plan....My plan is to order some industrial spray foam and seal the room to include the edges of my window ac which is mounted in my wall and cover my window with a 3m plastic insulation kit which is covered with a blackout curtain of course. Also thinking about covering my dry wall with panda film for a extra layer of protection. Its funny because in the winter when I dont need my ac Im able to use a 20lbs co2 tank for almost three weeks while maintaining 1000 ppm co2 level with my exhaust fan at half speed. Thanks!!!!

Skylander said:

Sounds like a plan....My plan is to order some industrial spray foam and seal the room to include the edges of my window ac which is mounted in my wall and cover my window with a 3m plastic insulation kit which is covered with a blackout curtain of course. Also thinking about covering my dry wall with panda film for a extra layer of protection. Its funny because in the winter when I dont need my ac Im able to use a 20lbs co2 tank for almost three weeks while maintaining 1000 ppm co2 level with my exhaust fan at half speed. Thanks!!!!

Click to expand...

Wow that's amazing, I was blowing through a tank a week . Sounds like she's air tight. What are you keeping the room at, what's the ambient temp of the garage and is the AC going outside or into the garage? Sorry if I'm asking a lot just curious, it's a weird set of issues, if all else is dialed in I would say it's the tent that needs more ventilation.

During the cooler months when I can actually grow I keep a daytime temp of 84F which is the recommended leaf surface temp for my LEDs(2x BD750s). I night I let it drop to 68F. I have two windows in my garage. One is inside my grow room and the isnt. The ac exhaust is going into the garage but I have a 22in fan (similar to a Air King)mounted in the other window that sucks that hot air from the ac exhaust out. Its very strong almost to strong. Sucks the door to my house shut when Im not careful. I dont have to use fan during the cold months.

Skylander said:

During the cooler months when I can actually grow I keep a daytime temp of 84F which is the recommended leaf surface temp for my LEDs(2x BD750s). I night I let it drop to 68F. I have two windows in my garage. One is inside my grow room and the isnt. The ac exhaust is going into the garage but I have a 22in fan (similar to a Air King)mounted in the other window that sucks that hot air from the ac exhaust out. Its very strong almost to strong. Sucks the door to my house shut when Im not careful. I dont have to use fan during the cold months.

Click to expand...

With a 20000 AC you should be able to get the room as cool as you like I would think. I would say your on the right track to spray foam the room