Grow tents in tandem in garage. How many BTU mini split?

What's up peeps?

I am having trouble trying to calculate how large of a BTU mini split to get.

18.00' x 18.00' two car garage. Garage is insulated with dry wall, and the garage door will be insulated. I will be putting sound insulation blankets on the garage door wall. This is going to be a stealth grow. Noise will not be an issue.

Tents will be connected with vent tubing and inline fans intaking and exhausting into each other. Same diameter and strength. This is to prevent positive/negative pressure in each tent, to prevent light penetration from the veg to the flower room, and to scrub the air since both fans will have carbon filters. Smell will not be an issue. Tents will be sealed with pallet stretch wrap in conjunction with tarp zippers.

Ambient temps 45°-63°F in the winter. 76°-93° in the summer. Record heat temps reach around 110° in the summer. Of course, lights will be ran at night. Heat, humidity, and power consumption will be an issue.



1 - 9.50' x 9.50' x 6.58' tent - flower room

-1a - 3X 1000w lights (2X 1000w lights in the summer, 3X 1000w in the winter) - Lights will be air-cooled from the air in the garage and exhaust into the attic. Ballasts outside the tent.

-1b - Dehumidifier.

-1c - Water chiller for DWC setup.

-1d - co2 provided by co2 tanks.



2 - 9.50' x 4.75' x 6.83' tent - veg and clone room

-2a - 2X T5 light fixtures

-2b - Dehumidification will be handled by air exchange.

-2c - Water chiller for DWC setup.

-2d - co2 will be handled by air exchange.



---mixwell

Cool project.
How to you intend to use the pallet stretch wrap and tarp zippers together ?

Good luck with your grow.

Holy Grail 888 said:

Cool project.
How to you intend to use the pallet stretch wrap and tarp zippers together ?

Good luck with your grow.

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I'm under the assumption that the tarp zippers have a "tape" side. I just need to get in and out of the tents. I'm over-sizing the tents for elbow room.

MXW3LL said:

I'm under the assumption that the tarp zippers have a "tape" side. I just need to get in and out of the tents. I'm over-sizing the tents for elbow room.

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oversizing ? please explain .. are you wrapping both tents up together ? like going over the original tent or just the frames together ?

thanks

Holy Grail 888 said:

oversizing ? please explain .. are you wrapping both tents up together ? like going over the original tent or just the frames together ?

thanks

Click to expand...

oversizing, what i mean by that is just getting a tent larger than i really need. 2-3k lights in that huge of a tent...

not wrapping the tents together. (they will be vented together, see OP.) going over the outside independently, but now that you mention it, i didn't think about just doing the frames and then running the cover of the tent over that! lol thanks for that insight!

yes..wouldnt it be better to shrink wrap the frames first . then use the tent over that.. then shrink wrapping again ?. Obviously you will need to cut the first layer .. but thats where youd be able to fix the tarp zippers.That shrink wrap stuff is cheap so why not have two layers and in fact . Youve made me want to do this to mine anyway as an extra layer for stealth. In fact wouldnt it be great to buy tent liners that had carbon in its material..

Holy Grail 888 said:

In fact wouldnt it be great to buy tent liners that had carbon in its material..

Click to expand...

only is a positive pressure situation though...

ohh i get ya. i mean as a disposable insert like a carbon fabric. really thin just to reduce smells something that lasts 6 months. not too heavy. anyway just a thought..

In addition to a basic J manual calculation one should add 3.414 btu/hr for each watt used in the room.

Generally, a 1000 watt lamp puts out between 3000-4000 BTU. Since you have cool tubes, some of that heat will get pushed outside so you don't have to cool all those BTUs. Plus you need to calculate room size into the equation. I think 12,000 BTU would do the trick with room to spare. A mini split smaller than that is a waste of money.

I'm cooling a 10x17x7 room with 4x1000w in cool tubes with 12,000 BTU. However, we never see a day over 30C in the summer here.

If your using cooltubes be aware that the makeup air will need to be conditioned unless it's within tolerance.

Medicanman said:

Generally, a 1000 watt lamp puts out between 3000-4000 BTU. Since you have cool tubes, some of that heat will get pushed outside so you don't have to cool all those BTUs. Plus you need to calculate room size into the equation. I think 12,000 BTU would do the trick with room to spare. A mini split smaller than that is a waste of money.

I'm cooling a 10x17x7 room with 4x1000w in cool tubes with 12,000 BTU. However, we never see a day over 30C in the summer here.

Click to expand...

Thanks for the insight! Can't tell you how excited I'm am to go this route.

SnapsProvolone said:

If your using cooltubes be aware that the makeup air will need to be conditioned unless it's within tolerance.

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Define "makeup air" please.

I believe he means the air the is replacing that which is removed from your tent via vented hoods?

And as far as 'reconditioning' I'm guessing he just means its at a temp thats within range of your tents temp. E.g.. tent is at 80°, if your new air is 55° it would need to be mixed with warmer air so its within about 15° of ambient temperatures

hydroMD said:

I believe he means the air the is replacing that which is removed from your tent via vented hoods?

And as far as 'reconditioning' I'm guessing he just means its at a temp thats within range of your tents temp. E.g.. tent is at 80°, if your new air is 55° it would need to be mixed with warmer air so its within about 15° of ambient temperatures

Click to expand...

it's going to be sealed... or am i being dense...?

Sealed yes, but if your running vented hoods, it does no good not to exhaust the hot air from the tent creating negative pressure. An inlet of some sort needs to be present for fresh air to replace the air being pushed through your hoods to keep temps down. I believe having it sealed is for insulation and humidity control.


Negative pressure is ok, but if your completely sealed, your fan will create a vacuum and a) u wont have proper air flow and b) your fan will be working harder to pull less air.

I'd suggest a heppa filter and just fix it to the inlet hole in the tent. Fresh air will be filtered and cool your tent. If you keep it sealed your going to be hard pressed running more than 400-600w and even then look for temps in high 80's

This will all depend on the limits of the mini split.

**sigh**

I hope it's not all hype lol

but with air-cooled lights, i will be pushing the air through. this will "leak" air creating a positive pressure situation. i'm contemplating having a twin fans on the intake and exhaust, just to balance the pressure...hmmmmm.

my sealed room will not have an exhaust fan. steps are being taken to avoid this.

By makeup air i do mean the air that will replace what is exhausted venting the air cooled hoods.

If your not using room air, where are you getting it from?

If filtered outdoor air is used to vent the hoods, will it always be acceptable temperature?

If indoor air is used, outdoor air will replace it thus increasing your heating/cooling bill.

Basically just cool the room with AC and forget blowing hoods then you can alsoditch glass and get more lumens.