Advice on managing environment

I could use a bit of counsel on managing my grow environment. I have a new room setup and I am having a bit of trouble managing the variables. I suspect that I have underpowered air conditioning, but I also want to get a better sense of what I need to focus on as I invest a few thousand into new cooling.

The room is 18x18x9’6" tall. I run Gavita 1000W Proe-e lights on SL2 controller (12 of them) and I intend to supplement them with another 12 315 CMS lights for some broader spectrum and UV. I grow indoor hemp for CBD.

The room is inside of a warehouse that is not air conditioned, and I live in the southeast. The warehouse temps go up to 100 regularly in the summer, and the humidity here is 80% regularly. We also have wild temperature fluctuations in the fall and winter that really keep you moving to manage temp and humidity. Achieving ideal VPD is a challenge to say the least. Staying in the curve is nearly impossible with what i have.

This week, I harvested the first crop (very successful grow) and have rotated in the next plants, and while I’m managing the temps well (using only 9 lights while they stretch in transition) I am seeing good humidity levels of 40% and thus the temp is easier to manage as well.

What I am hoping to learn from the other members is what are the steps to getting this environment stabilized? In other words, what piece of equipment do I focus on first? The AC? Do I need independent Dehumidifier or is Mini Split sufficient? I do not run CO2 now, so I try to keep my temps down around 74 with lights on. The room is insulated on walls and ceiling. i am contemplating using a spray foam on the entire exterior to seal it up and improve the R-factor more.

Room has 3 AC units (39K BTU) These are to be replaced with 2 Mini Splits in near future. 6 wall fans on canopy, 2 fans on underside, CO2 monitoring at 350-400 regularly.

I typically run my lights at night so the AC isn’t fighting daytime temps and the light heat.

I look forward to any advice on how to approach my next major expenditure on the room.

Thanks to anyone who has experience with this type of a room or situation.


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A quick question - what kind of AC units do you have in there right now? Are they the portable kind?

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I have a couple of dual-hose Ideal Air 14K portable units and an 11K window unit. these were set up in haste and not intended to be the primary AC, but rather the redundancy in the even fo a failure.

Hey Larf!

As Peter mentioned, if you are using the portable style A/C units, they are likely hurting more than helping as they in general are not very efficient – but also if you are using a NON-dual hose portable, then all it is doing is creating negative pressure in the room and sucking more hot air from the hot warehouse.

Mini splits are great, I use the Mitsubishi Mr. Slim’s myself. Depending on the room dimensions and how many rooms, you can run multiple rooms on a single multi-zone minisplit unit if you run the days/nights at different times. This will allow you to get more coverage and 24/7 utilization of the condenser units. Either way, check out the multi-zone units to get more coverage (the shortcoming of minisplits is making the cool air reach all areas of the room, multizone units help spread it around similar to ducting.

I would seriously consider switching to a sealed room (along with extra insulation) with those kind of external temps/RH. It will require some effort but overall increase in the quality of product (and personal life) will be worth it! The main things you will need are CO2 burners (don’t waste your time with lugging tanks around) and extra dehumidification. Both are an investment but it will save you a ton of headache in the future because trying to run an unsealed room in your harsh climate is always going to give you inconsistent results unless you really go overboard on equipment and controls. You can successfully aircool hood’s even with a sealed room by putting your exhaust fans at the beginning of your loop as an intake pushing air through and out of the hoods (not sucking out your precious CO2). All that said, it’s really worth considering a standard A/C unit with ducting depending on your situation (power, funds, how long you intend to stay, etc).

The minisplits also double as dehumidifiers so that may take care of some of your RH issues. That said, always invest overkill on your dehumidifer as a rule of thumb. The development of harmful mold and bacteria takes time and will go unnoticed until it’s fully establish and the only way to reset that is a full operational shutdown and sterilization. I’ve done it, it’s not fun!


Like said earlier bigger units ac and dehumidifiers. Also but sounds like when your hids need upgrading get less. the technology has come along way. Trust me ran hids for 18 years. Converted to led almost 2 years now. The prices are coming down also.even at a super high price they pay for themselves just in bulb replacement not to mention your acs work no where near as hard. Took me a little bit to adjust but once I got a couple of the pulse meters I was able to really get things dialed in.