Too hot in room

Discussion in 'Grow Room Design/Setup' started by Rabble, May 30, 2019.

  1. The room is about 10 feet wide by 16 feet in length and a height of about 7 1/2 feet.

    I have 2 x 1000 Watt umbrella hoods in there and I'm running 2 portable ACs each venting outside and I'm also running 2 inline fans going out from the back of the room to bring the heat out and then 1 inline fan closer to the other side of the room venting out from another ducting.

    I can't seem to keep the temperatures below 88, there are only about 9 plants in there which is below the legal limit for having plants in Washington DC.

    I know there's a ratio for how much heat is pulled out of the room and how much cooling is being put in the room but I don't understand that very well as I'm not so HVAC qualified.

    When I close the door to the room you can clearly tell there's negative pressure in the room because right by the door if I put any kind of paper it will get sucked in through the bottom, very lightly not so strongly.

    In my opinion, I feel like there's a lot of heat being created by these umbrella hoods and there is cooler air being created by the ACs' but the cooler is not able to overpower the hot air and I've tried everything from hooking up fans facing from one direction of the hoods to a 6inch ducting on the other side, with an inline fan sucking air in, where the fan blows the heat off of the bulb into that direction if the ducting and nothing seems to change temperature to cooler.

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  2. It sounds like you need to provide a way for more air to enter your room but that may not be your problem. The only thing I can think of is to get different hoods to allow hot air from the lights to be vented outside.
    • Agree Agree x 1
  3. Been Here done this:

    Removed the very expensive Hoods

    we have the choice of great reflectivity or great cooling

    but not both ...yet

    good luck
  4. Sh*t! Really?? Dang!!!

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    • Funny Funny x 1
  5. True back in 1992 those Chinese hat type reflectors cost a bomb?

    I had a choice like you of great reflection at high temp


    normal temps with poor reflection


    I bleed more and bought a light meter $35?

    and found the reflectivity was not great in the first place

    due to the hi gloss white paint

    even to day this stumps many expeirenced growers

    • Like Like x 3
  6. I had a room of similar dimensions with 2x 1000 watt lights, though they were in enclosed hoods. I had ductwork and a centrifuge fan pulling air over the lights and out of the room which helped a TON but it still got a little toasty. If the AC units aren't doing enough, you may need to upgrade your hoods so that you can pull the hottest air out of the room constantly.
  7. What's crazy is that when I go outside and check the vent out for the air that is coming out of the room, that air seems cool, no matter where I place these ducts.

    Here is an update to see this will help. 20190530_224510_HDR.jpg

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  8. Yip thats what I had

    but I did use them for Metal Halides at the time

    for the HPS ? then made my own much smaller reflectors

    still running to this day

  9. Yeah, that doesn't look like you'll be able to efficiently draw heat away from those bulbs and you're also sacrificing some of your reflectivity having the ductwork where it is. Can you show more pictures of the box? You may be able to set up the air in/out to cycle air in the box more effectively.
  10. Doesn't matter how much air you bring in if the incoming temp isn't low enough. What's the temp of the incoming air?
  11. By box you mean room?

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  12. No outside air, maybe from the other room next to this room. Outside temps here are well above 95 degrees, that's why.

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  13. You need to bite the bullet and get enclosed hoods so you can vent the hoods directly. If possible window AC work a lot better then the portable ones. If not try to setup the portable AC as close to possible to the vents outside. So that the AC ducting is as short as possible. Once that’s done, wrap a space blanket around the AC ducts and then bubble wrap it. Your trying to insulate the ducts so heat does spill out of them and back into your room.
  14. I'm talking about wherever you pull fresh air from. If it's from the room what's the temp of the room?
  15. If your portable a/c’s are in the grow room remove them. Find somewhere outside your grow area to set them up then run ducting to the grow area. The a/c’s can only cool air to an extent. The hotter the air coming into the unit, the hotter the “cooled” air is. Putting the a/c in a cooler area will allow better cooling. The machine will be able to put out the coolest air it’s possible of producing. Having it in the grow area reduces how cool it can get because the air is already so hot.
    • Like Like x 1
  16. Nice! Thank you!

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  17. That room had no AC, and is adjacent to this room, the temps of this room Hoover around about the same as outside temps.

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  18. Interesting, I always thought the opposite. In that, the hotter the air I can get into the AC the cooler the room will become.

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  19. The hotter the air the a/c is trying to cool, the harder it has to work to cool it. A/c’s constantly push air through the unit. So it takes a longer time to cool hotter air because it can only affect the air little by little. When the air gets too hot it’s only cooled very little before passing back out into the atmosphere, then back In. So it takes in 80 degree air, cools it to 79 spits the air back out. Then it sucks in 79 and spits out 78 then so on and so forth. So with 88 being the coolest air it can get in it can only put out 87. Please understand these are real numbers just an example. The point is that an air conditioner can only cool air to an extent. It cools most effectively when the air it’s taking in is cooler. They can only cool the air so much before they are working as hard as they can.
    • Like Like x 1
  20. Please try relocating your ac units before you buy anything else to try to fix this. I’m pretty sure that’s your answer. I was having slight temperature issues causing my tents to reach 85. I moved stuff around and now I’m at 72 and 77 for today. I didn’t buy anything new, just moved things around so that everything can work to the best of its abilities. Set your ducting up so that the intake is where the cool air is blowing from and your online fans will pull it in. In addition, every piece of electronic equipment you can remove from the grow space will help. Fans and all that shit creates heat too, so having them outside the room would help ever so slightly as well.

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