So I'm not sure if I should size the mini split the same way I would hps. I'm going to be running around 2400 watts of led over a 5x10 flower area in a 10x12 foot space. Eventually I'd like to build 2 more fixtures if these work well. I was thinking 18000 btu or 24000 btu mini split. I live in a very warm dry area.
Mini split for led room
- Thread starter Rdot03
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Renfro
Well-Known Member
Being that it's a minisplit you can oversize it and it has the ability to run at reduced levels compared to a normal AC unit that is either ON or OFF.
you will want to spec a unit that has "Restart after power outage" feature and if you think that you will need the AC in the winter you will want a low ambient capable unit. Some units will run down to -29F (mitsubishi). If they don't have low ambient functionality then the unit will freeze up or just stop working when it's too cold outside, generally in the 50's.
you will want to spec a unit that has "Restart after power outage" feature and if you think that you will need the AC in the winter you will want a low ambient capable unit. Some units will run down to -29F (mitsubishi). If they don't have low ambient functionality then the unit will freeze up or just stop working when it's too cold outside, generally in the 50's.
I was hoping the mini split would take care of humidity and no it's a garage that's probably 80 90 ambient. I'm going to start logging temps as I build my room.
Ok I'll look into it. Where I live it doesnt snow barely reaches freezing temps in winter.
Renfro
Well-Known Member
Well definitely insulate the room as well as you can when you build it.
When you need more dehumidification than you need cooling then a dehumidifier is going to be in order. Using LED lighting will mean the AC doesn't have to run as much and thus it won't dehumidify as much. That can become an issue when you have enough biomass in the room. Also when the lights are off your AC won't be doing any dehumidification and thats when people usually have spikes,
Renfro
Well-Known Member
The roof only has to be cold enough to condense water.
Since ambient is so high here at night I figure I'd run ac 24/7 I'm going to start with 5 plants.
Renfro
Well-Known Member
Just don't put yourself in the common noob situation where halfway into flowering the humidity levels are too high and last minute dehumidification has to be figured out. I have seen it so many times on here, people with their budget spent and at like day 40 of 12/12 they are stressing on how to dehumidify or get bud rot. Either have a dehumidifier handy or be able to purchase one quickly if needed. You would be surprised how much water the plants can transpire when they are big. Things may work good until right about when low humidity levels are critical and the biomass crosses that threshold of dehumidification the AC is able to do. When that happens the levels will spike like crazy since they will just continue to rise as the AC lags behind.
Thanks I will definitely keep it in mind. Do you think a 12k would be good when I up my watts to 4500 eventually.
Also do you have any suggestions on mini split brands?
Renfro
Well-Known Member
Well Mitsubishi is the best IMO. Expensive though.
I have some cheapo Midea 4 ton ceiling mount units that have served me well.
Renfro
Well-Known Member
nevergoodenuf
Well-Known Member
Let's start with the lights themselves. Are you talking 2400 fake watts from a red/blue panel you found on Amazon or are you talking 2400 watts at the wall with a quality white led light? If you're talking true wattage, then almost 50 watts per square foot is a bit intense. Using COB leds, I flower between 20-40 w/sf, with 30 being my sweet spot.
Another thing is room temp under white led will be higher, my room stays between 79*-86*f with or without CO2. Because of this, I have not had to run my Mini spit in a couple years. Just 2 8" Hyperfans for intake and exhaust hooked to a temp/humidity controller (turns on at either 86*f or 60%rh). For winter a dehu for heat and CO2 because the fans seldom turn on.
Itll be true watts I'm building 2 9 cobb fixtures running vero29 gen 7 c @1750. Right now it would be lights out and the ambient temp is 92.
OldMedUser
Well-Known Member
I had to go look up mini-splits and figure I need me one of those. Was going to go with a portable AC init to set up a sealed room but they use up room air to cool themselves.
I wasn't aware that the external unit can freeze up like @Renfro mentioned and we get down to -37C sometimes so I'll have to rig it to keep it warmer when the deep freeze sets in.
An LG 9000btu unit I was looking at has a dehumidification mode to pull extra water out of the air. I shouldn't need that too much but nice to have I guess. I plan to capture the water for reuse. Already have thermostatically controlled heat in the room so may be able to take that out with the mini-split.
The 9000btu mini is only about $300 more than the 8000btu portable I was thinking about.
Learn new stuff every day!
I wasn't aware that the external unit can freeze up like @Renfro mentioned and we get down to -37C sometimes so I'll have to rig it to keep it warmer when the deep freeze sets in.
An LG 9000btu unit I was looking at has a dehumidification mode to pull extra water out of the air. I shouldn't need that too much but nice to have I guess. I plan to capture the water for reuse. Already have thermostatically controlled heat in the room so may be able to take that out with the mini-split.
The 9000btu mini is only about $300 more than the 8000btu portable I was thinking about.
Learn new stuff every day!
xox
Well-Known Member
im also finding it difficult to size a mini split, if you oversize your mini split it wont run enough and not enough dehumidification will happen and the mini split itself will freeze from what i understood. i got have an hvac contractor coming to my place to install central air for the house, at the same time i've been speaking to him about installing a mini split for my 10x10 room. my hvac contractor an i were speaking about what to do in -37c temperatures since the mini split wont run with exterior ambient temperatures like that. he proposed we rig up a motorized intake and exhaust with a damper on a thermostat for the winter time. im unsure how that will play out with rh%. im thinking about 24,000 btus or 30,000 btus for 4k of light still unsure i dont want to oversize thats just my two cents hopefully it helps.