Cooling grow room in summer

Discussion in 'Growing Marijuana Indoors' started by Catlos, Jun 20, 2017.

  1. So i have a 4x4 grow tent in a 12x12 room im running a 6bulb 230watt t5 light a 440cfm exhaust fan blowing outside and 1 osilating fan and i have 2 passive intake holes open.the tent is at 82°degrees in the dead of night with the lights on but in the afternoon when its hot outside the tent can reach up to 85-90°degrees with/without the lights on.

    my question is if i put a 8,000 btu window ac in the room would it help cool the tent or would all the cold air just be sucked away by the exhaust fan in the tent? Anybody got a better idea? Also do i need a intake fan?
  2. WHAT TIME DOES YOUR LIGHTS KICK IN...?,,,,U can beet day time temp by only running your lights at night..its much cooler .never, put the 12/12 on in the day time ..u have to much heat with your lights and the heat of the sun of the days to deal with,,,set your timer to come on at like,,8or 9 or 10 at night so to beat the sun in the day,,I only run mine at night time ,,my lights come on at 8pm ond go of at 8am,,,that way I dont have problems with the day time temps,,,good luck
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  3. Yes u need an intake fan,,,a 4" will do it,,,depending on which rvk fan you use with your carbon,,a tent your size would be fine with a 5"rvk and carbon filter,,so a 4 "intake will be ok,,u want negative pressure in your tent,,this means that your out take eaqales the air going out and the air you intake,,cos the size difference
  4. My light comes on at 8pm an turns off at 2pm i am vegging right now so i tried to have the lights kick on after it cooled off outside but theyre on just long enough for when the house is the hottest or getting there
  5. If your lights are led heat isn't likely to be an issue unless your climate is hot naturally. 12/12 in the daytime has the benefit of being able to put the plants outside if that's a viable option for you (although for most it likely isn't)
  6. Yea second that if u can put outside ,,,
  7. Theyre flourescent t5 lights so the generate a good amount of heat and i cant put my plants outside during the day cause they think its night time, but do you think cooling the whole room with a ac would help with the heat during the day i would only have to run it for like 3hours an try an trap the rest of the cold air in there till the sun sets, but its about 80°degrees+ everyday thats why im having heat issues
  8. Of course, but I don't know how well/how long it would keep it cool after you turn off the ac.
  9. yes, a/c solves everything. Ambient room temp set at 80 should work, keeps my grow closet at 82. Also keeps humidity down. Open tent doors when lights are on if possible.
  10. Same for me in the wintertime - it's always coldest at night (Maine) so not only do I run lights at night (5pm to 5am) but do the same in winter to keep things warmer.

  11. Get a 10000 btu...i tried 5000 and 8000...10000 does the job with less run time.

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  12. buy the right size A/C, for your space, your space is 12x12, 144sqft.
    5000-6000BTU is what you need. Remember, running a bigger BTU a/c machine will run less, but running less proves to be less effective. this is because the A/C wont properly remove the moisture in the air because the run time is so short.

    Also, a 10-11,000 BTU A/C machine draws around 9-10 amps, that's a shit load of power.
    I run a 5000btu machine in a 10x5x7 feet tent, works really good, and it only draws 6 amps.
  13. i love the summer time its so nice being able to to take the boat out fish or just sit on the porch listen to music drink a modest 50 beers and smoke . but fucking the hot and a grow room is so shitty murder the ac and dehumidifiers . first time even shut down every thing for the hot months not thinking twice . good luck trying to keep your tent or rooms cool with out pumping a shit load of power into ac units .
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  14. You might be able to get it a few degrees lower. I have a 3x3 with a LED panel, exhausting in the same room with a 5200 btu on the window. A few days ago it was 34 celsius outside and with the AC full on, I managed to keep it at 29 in the tent.

    Luckily I live in Canada so it's usually not too hot, in hot states I think you might wanna look into a more powerful AC unit.
  15. A lot of times you'll pay a lower electric bill with the smallest AC you can get away with. Short run cycles on AC are not a good thing. Electric motors and the refrigeration system don't reach peak efficiency until they've been running for 10 minutes or more and everything has reached operating temps. The start up amps on an electric motor is a spike that can be 10x what it draws when it's running. Motors starting and stopping often draw more electricity then an even run time.

    That's why equipment sizing is always very critical and done by experts using computer programs that calculate heat loss. I would go with the smaller 5,000 btu AC. It's going to be half the electricity to run most likely it can run twice as long for the same amount of bill. It will also remove more moisture with the longer run cycle. Many growers run AC to help keep humidity levels under control as well. If you size it for the hottest day of the year the whole rest of the year it costs you more money and it also costs more to purchase.

    Not a lot of people know that a dehumidifier is an ac that has the hot condenser in the same box as the evap that is collecting moisture. It's an AC running in circles making more heat for the space. You're much better off with a real AC if it doesn't make things too cold. Get a small one and it will run long enough to reduce humidity significantly as well.
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  16. Good AC flow is mandatory, both for temp and humidity.
  17. Watch your RH drop when your AC turns on.
  18. You think it would be more cost effective to buy another 440cfm fan an have it pushing air into the tent but then id be pushing in like 82°degree air from the room
  19. You shouldn't need an intake fan with a large exhaust fan. Just make sure you have enough intake ducts open. I use an 8' piece of 6" duct run in a half circle around the back of the tent for intake so it doesn't spill light. No intake fan.

    If your home is 68-70 which it should be that's a great intake temp. Home air is usually fairly dry as well. If it's just plain too hot in the room your tent is in a window ac should be able to cool that room and the intake air for the tent down enough for you to maintain temps. I'm surprised you can't. You don't have very much lighting.

    I'm running 770 watts of platinum led in just my flower side. About 1000watts total with veg and bloom. I'm pretty sure that's way more heat then your t5 fixture. I also run a 440 cfm apollo exhaust fan and my tent is 80-82 on a warm day when it's 70-75 outside. If I open my other window and put an intake fan in it I can get the temp down to 78 or so even on a 70+ degree day.

    Your exhaust fan is ducted outside via a sealed duct right? So the hot air in the top of the tent gets dumped outside? All intake air should come from the house. Many states it's illegal to build a residence without AC. Most home air is plenty cool enough to cool a grow tent of reasonable size with just the exhaust fan.

    My buddy does 2100 watts in a 5x5 with no ac. Just an exhaust fan.
  20. 5×10 , 1 600 watt hid , good exhaust etc etc.....bought a 5000 btu when it got 80 outside . That pos wouldnt keep it 85 with light on. And thats a cooltube with its own ventilation. There 2 choices here. Are you going to leave it on and set the temp on the ac itself or run it with a temp meter?

    If you can leave it on , that would be best, but if not run a temp meter .

    Also i had to get a 10000 btu just for my space , a 5x10x7....

    I would suggest a 12000 btu

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