Mini Split Sizing

[merkaba]

So, I am about to set up a new space. It is 12 x 18 x 8. Concrete floors and block walls. It is underground on 3 sides. I plan to put in 6 1kw lights, Co2, ballasts are in another room. It gets about 85-90 here on average in the summers, cool in the winters. My buddy swears to god i need to get a 48k BTU Mr. Slim. That seems like overkill. Any thoughts? I may or may not air cool the lights as well.

Thanks

Am i the only one that has a weird delay when typoing on this site?As far as the letters making it on to the page?

 

[Medium Pimpin']

2k btu per 1k lighting is a good rule of thumb.

 

[dalilguy]

Air cooled or non hoods? Summers here are rough an running non air cooled I need about 4k btu per 1k

With a 2 ton you should be good but a 2.5 ton will serve you right.

 

[FlowerFarmer]

2k btu per 1k sounds awfully low to me. Is that really all you need?

I'd shoot for 4-4.5k per every 1000w of light.

I went 36k to hopefully cool 8k in full go, however that is not including the co2 generator. I like the 10 burner adjustable from Sentinel though which allows me to run any numbers of burners to get co2 to levels quick and turn back off.

 

[merkaba]

Did that 36k do you right? What are your average summer temps and what were you able to keep the room at?

 

[prune]

2k btu per 1k sounds awfully low to me. Is that really all you need?

In Alaska, yes.

 

[Phillthy]

i run a 30k unit for almost 6k watts sealed no hood cooling. never goes above 76% even when it is 105 outside. it is a mr. slim unit.

 

[FlowerFarmer]

Did that 36k do you right? What are your average summer temps and what were you able to keep the room at?

Its actually a 33,200 BTU for cooling - heat pump model which says to 36k.

I only got it installed later in the summer/going into fall so never really ran it in full force. I'm also only currently running 6400w and a generator set on 7 burners vs. the 8000w that I'd like to be able to cool in full go/ even in summer. Right now I have full control. We'll see going to full wattage in the summer.


Summers around here get 80-90s with last summer hitting 100F for a couple hot weeks. Luckily I'm in a 2in foam board room that is sort of built into a hill. Unfortunately the side of the house that isn't sitting in the hill is exposed to good sun all day.

 

[Phillthy]

if it is working now then i dont believe you will have an issue come summer.

 

[merkaba]

So, a 30-32000 btu should be fine you think?

 

[the gnome]

So, a 30-32000 btu should be fine you think?

yes, you'll do fine with the 32.500btu

I am in the process of building my own 6KW room, i picked up a 32,500btu mr slim
the room is sized for 8kw, but i will probably have to air cool to do that.
insulating is a big factor how efficient cooling/heating will be.
I'll have solid 3-1/2" eps foam walls on the 2 walls being built
the 2 existing concrete walls get a 2" maybe 4" eps foam lay over.
it will have the efficiency of a walk in cooler

5000btu per 1000w non air cooled seems to be the norm

 

[Cali MedPatient]

I always try to get one a little bigger than I need. That way it won't run quite as often, will be able to handle the heat if there's a heat wave, and you never know, you might end up adding another light or two some day. I think it's better to have more a/c than you need rather than an undersized one that struggles to keep the room cool.

 

[merkaba]

My buddy has a full basement, probably 35 x 20 with a room built out of foam board in one corner her blooms 4 lights in, super cavernous and drafty space. He was fine last summer with a 32000 btu Mr. Slim. That being said, I think I will be ok as this space is a) smaller and b) way better insulated and underground on 3 sides.

 

[ZinksInk]

48K minisplit is going to be overkill. Id go with a 30 or 35. I have Bell lab hoods which are not air cooled. I use to have 17 SEER Samsung 2.5 ton minisplit which easily could handle 6K. I don't think i've ever felt so comfortable in a grow room. It could run up to 4 indoor units which I liked for more even air conditioning/distribution. If you can cut the extra holes in the wall id recommend getting one of these. They do cost a little more and are a little more work should you need to repair the house, but that will give you more options(IE one unit for a veg room and the others to flower). A thing to note about a multi room minisplit though is a lot of them will require at least 2 indoor units hooked up.

Im currently looking at getting a new minisplit system for the current place. What concerns me most now is highest SEER. i'm looking at doing an LG this time.
Cant decide between the 24,000 BTU 20 SEER or the 30,000 BTU 18 SEER...

http://www.goductless.com/ has pretty good prices and free shipping. Let me know if you all have a different preferred supplier.

 

[merkaba]

What were your summer lights on temps running that 2.5 ton?

 

[merkaba]

How low could I go BTU-wise if I actually air cooled the hoods ?

 

[NorCal]

I run an 8k non air cooled room easily with a 33k fujitsu mini split. This thing Is so quiet even when it's running full throttle. At max pull it uses 8 amps so pretty efficient IMHO. The ballasts and generator are all in the room too. It stays a constant 75. You dont need that big of a unit but The idea of having one that's bigger than necessary isn't a bad one. It'll run quieter because it won't be running full throttle to keep temps in check and it will save energy because it doesn't have to run as much to keep your temps in check.

 

[Mister_D]

Personally I estimate 4k btu per 600w or 5k btu per 1000w. This is for non-aircooled hoods/vert bulbs in a sealed room, and accounts for equipment (ballast, co2, pumps, etc) heat also. This is just a base to work off of, if your spot is poorly insullated or in a very hot enviroment for instance, add another 1-2k btu per light to account for the extra heat.

 

[TribalSeeds]

Fuck the bullshit! You need more than 1 AC. Infact you might want more than 2 smaller ones. Fuck the bullshit! Im done with it!

 

[NorCal]

Oh and I'd never air-cool my hoods if i was trying to run a sealed room. Co2 always finds a way to escape through the hoods. And the whole point of a sealed room is to maximize yields. The glass def robs you a good chunk of lumens.

Just my opinion though. Def tried it before and after masking off every damn piece of ductwork and the glass on the hoods I end up taking it all apart because my co2 levels were diminishing pretty quick requiring my gen to come on more often, In Turn heating up my room.