Mini split advice, wall mount vs slim duct, C&H vs Aircon

looking at 24k btu mini splits to cool a 12x15 flower room running 6000ish watts of led+cmh, I have narrowed it down to a couple of choices, either THIS 21 seer wall mount unit by Aircon, or THIS 20.5/21.5 seer unit from cooper & hunter. Looks like they both use the same CMGG Toshiba compressor, are about the same efficiency when using the standard wall mount indoor unit. The C&H unit has an available slim duct version that bumps it up to 21.5 seer, and gives me the option of mounting to the ceiling and using some ducting if needed to control the air circulation. This brings me to my main hangup, the ceiling height in this basement is only about 7'6, and I grow very large plants so there isnt a ton of room for ducting on the ceiling, and I have 2 ultra aire 100v dehumidifiers I need to duct to some degree, as well as a 10" max fan and filter that I usually prefer to duct to the other side of the room. In the past at other locations have just run ducting and hung equipment above the lights, but the combination of low ceilings and switching to large bar style led's has put ceiling real estate at a real premium. I was thinking I would either mount a wall unit in the middle of the 12' wall, as high and close to the ceiling as I can, OR mount a slim duct unit to the ceiling about 2 feet or so away from the 12' wall blowing towards the other 12' wall. My plants/lights are in 2 5x15' rows up against either 15' walls, so either way the ac would be blowing down the middle to some extent, with some wall fans at the far 12' wall to blow the air down the rows of plants. Typing all this out makes me think I am better off with a wall mount unit, although in theory I would prefer the more flexible and rugged design of the slim duct unit.

I guess what I am looking for is some input on peoples experiences with mini splits and low ceilings, Wall mount units vs slim duct units, and any experience anyone has with either the Cooper & Hunter or Aircon brands. There doesn't seem to be a ton of difference between them on paper, except the Aircon brand has a gold coating on the fins of both the outdoor and indoor unit, and the C&H has them on the outdoor unit only. They Both have low ambient cooling down well past where I think I will need it, and they both have auto restart.

Thanks in advance for any input anyone has, I have never lived or grown anywhere that has basements before this, Love how its naturally cooler down there but the low ceilings and lower air volume that goes with it sure adds some nuance to controlling the environment and mounting equipment.

Can you mount the slim duct unit in an adjacent room and duct to and from the room?

i think 24k is a bit low for 6000 watts, are you planning on mounting all the drivers for the leds remotely in a different room with your flip box?

i installed a mini split on the wall in a basement growroom with a similar height its a bit tricky just hafta be gentle with the copper lines when your bending them through the hole in the rim joist and over your wall framed in-front of the concrete.

Do this math.... figure up ALL the BTU's you'll be using at the max. Lights, dehueys, Co2 generator, or anything else that makes heat ... plus some. Then double that number. This is how many BTU's of AC you will need. Why double?... well, during 18/6 light cycle, the heat really builds up.

My total BTU's generated is about 18,000. I have a 3 ton AC mini split, and it does the job.

yeah I went with 6k watts as just a sort of round number and to give me some leeway, the total wattage of the led's is 5140. I cooled it with a 18k window unit last fall/winter and it worked fine, so I figured getting a 24k unit would give me some more leeway as I got much more efficient dehumidifiers since then, and switched the rest of my hps lights for led's. Its in a basement so that might be why. But the total equipment wattage is 6976w with both dehumidifiers, I am planning to put the dehu's outside the room and duct them in but I wanted to get the mini split installed first so I could see how the air moves and decide the best place to have the supply and return ducts. I counted their wattage in my total though even though they arent going to physically be inside the room. I guess my biggest concern right now is the air movement, I have never grown anywhere with low ceilings like this before and dont want to end up with stale air anywhere, that was my main interest in the slim ducted units, I could use some ducting to ensure good air circulation. Does anyone have any experience with C&H or Aircon brands?

MikeMuffler said:

Can you mount the slim duct unit in an adjacent room and duct to and from the room?

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not really, I am removing a couple blocks from the walls for my dehumidifier supply and return ducts but I would need more and larger ducting for the mini split. I am renting this space from a friend so I would rather not cut any more holes in the block than the ones I just mentioned. For those I was planning on putting a room to room vent in when I leave.

xox said:

i think 24k is a bit low for 6000 watts, are you planning on mounting all the drivers for the leds remotely in a different room with your flip box?

i installed a mini split on the wall in a basement growroom with a similar height its a bit tricky just hafta be gentle with the copper lines when your bending them through the hole in the rim joist and over your wall framed in-front of the concrete.

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yeah there are going to be some bends in the lineset that might be a little tricky, I was just planning to go slow and careful, I have a conduit bender but was going to check and see if there was something more specific for the smaller copper tubing of the mini split linesets. No, drivers are all mounted on top of the led bars. Going to check some prices on 3 ton units, seems like everyone here thinks 2 tons won't be enough. last fall/winter I was running 3000w of hps and 1600 watts of led in this room, plus almost 2k watts of portable dehu's and cooled it with an 18k btu window unit, So I thought 24k btu's would be enough, especially since I have switched out the hps for led, and replaced the portable dehumidifiers with much more efficient ducted units using 500w less for the pair. I could be wrong though since that was the fall and summer is coming up, after spending the coin to upgrade all my other gear I dont want to find myself in a situation where I cant control the temps in the heat of summer. I do need to get plants back in there asap and cash is getting tight though. How did the mini split work out for you with the low ceilings? did you have problems getting good air circulation?

watsongreenthumb said:

yeah there are going to be some bends in the lineset that might be a little tricky, I was just planning to go slow and careful, I have a conduit bender but was going to check and see if there was something more specific for the smaller copper tubing of the mini split linesets. No, drivers are all mounted on top of the led bars. Going to check some prices on 3 ton units, seems like everyone here thinks 2 tons won't be enough. last fall/winter I was running 3000w of hps and 1600 watts of led in this room, plus almost 2k watts of portable dehu's and cooled it with an 18k btu window unit, So I thought 24k btu's would be enough, especially since I have switched out the hps for led, and replaced the portable dehumidifiers with much more efficient ducted units using 500w less for the pair. I could be wrong though since that was the fall and summer is coming up, after spending the coin to upgrade all my other gear I dont want to find myself in a situation where I cant control the temps in the heat of summer. I do need to get plants back in there asap and cash is getting tight though. How did the mini split work out for you with the low ceilings? did you have problems getting good air circulation?

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well the thing about mini splits are the condensers are variable meaning it will only use as much electricity to cool as it needs to. for spending a few hundred extra on a larger btu unit id say thats a small price to pay for insurance vs tearing it out later for a larger one. well i just planned installing it very carefully i bought a unit that had pre charged line sets. the first day i had one friend come and help me mount the condenser on the building with a large bracket to keep it off the ground. the next day i had two people help me i had one friend stand outside the building to received the lineset through the hole the other friend held the air handler while i uncoiled the lineset and gently passed it outside to my other friend the copper lines can bend easily by hand just be gentle is all try not to be too forceful. i didnt have any issues with air circulation however its a sealed room i had a few oscillating fans and i also had a six inch fan+carbon filter also circulating the air and co2. the other thing is my room is not as large as some rooms my room is only 9x12? i think with a 24,000 btu split, and a very small 2 burner natural gas co2 generator. last summer i ran the room with 4x 600watt single ended bulbs so 2400 watts and things went fine for cooling if your curious i took photos as i built the thing i think it starts here but youll hafta scroll through some convos about other stuff

xox said:

well the thing about mini splits are the condensers are variable meaning it will only use as much electricity to cool as it needs to. for spending a few hundred extra on a larger btu unit id say thats a small price to pay for insurance vs tearing it out later for a larger one. well i just planned installing it very carefully i bought a unit that had pre charged line sets. the first day i had one friend come and help me mount the condenser on the building with a large bracket to keep it off the ground. the next day i had two people help me i had one friend stand outside the building to received the lineset through the hole the other friend held the air handler while i uncoiled the lineset and gently passed it outside to my other friend the copper lines can bend easily by hand just be gentle is all try not to be too forceful. i didnt have any issues with air circulation however its a sealed room i had a few oscillating fans and i also had a six inch fan+carbon filter also circulating the air and co2. the other thing is my room is not as large as some rooms my room is only 9x12? i think with a 24,000 btu split, and a very small 2 burner natural gas co2 generator. last summer i ran the room with 4x 600watt single ended bulbs so 2400 watts and things went fine for cooling if your curious i took photos as i built the thing i think it starts here but youll hafta scroll through some convos about other stuff

Not Another Grow Journal

wow i've been busy busy busy since the holiday season has kicked off. things have progressed alot since my last update things are going very nicely. the mother plant i moved her to her own tent seemed like the right move. i have all the clones vegging under some fluorescent lights. as for the...

www.rollitup.org

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Yeah I hear you, those 3 tons are heavy for sure, had to help lug a 3 ton unit up 3 flights of stairs and through a window onto a back roof years ago and I think my back still hurts. That might be the reason I seem to have some strange aversion to going bigger than 24k, since I will have to do the install mostly by myself. How did you like the pre charged linesets? I have never used those before how do they work exactly? do you think it was easier than just pulling a vacuum once you got everything hooked up/ would you go that route again? I have a 10" fan and filter combo that does a great job moving air around if its setup right, so I think I am going to go with a wall mount unit and save the ceiling space for other stuff. I Checked out your thread, Nice tight framing work!! I am a carpenter by trade as well, after seeing those walls I know for sure you guys up in the great white north are keeping all the straight studs and sending us the twisted ones. Haha just kidding but I gotta ask, Is the price of wood as crazy up there as it is here? a 2x4x8 is going for almost $8 bucks here now, seriously considering buying a big tent for a veg room as it would be cheaper right now and I could use it again if I have to move. One last thing, How have you liked the Mr cool unit you have? Any problems or anything? Also really curious as to how the precharged lineset works? What do you do with the extra length? I am assuming the lineset has some sort of valves to keep the refrigerant inside so you cant cut it to length?

PS I LOVE those epoxy floors, I used the one part rustoleum epoxy from lowes when I first built this room last fall, was all I could afford and better than leaving them bare, but dang I cannot wait to lay some nice white 2 part glass in there after this next run. Yours look amazing and I am sure they look even better in person, What product did you go with?

watsongreenthumb said:

Yeah I hear you, those 3 tons are heavy for sure, had to help lug a 3 ton unit up 3 flights of stairs and through a window onto a back roof years ago and I think my back still hurts. That might be the reason I seem to have some strange aversion to going bigger than 24k, since I will have to do the install mostly by myself. How did you like the pre charged linesets? I have never used those before how do they work exactly? do you think it was easier than just pulling a vacuum once you got everything hooked up/ would you go that route again? I have a 10" fan and filter combo that does a great job moving air around if its setup right, so I think I am going to go with a wall mount unit and save the ceiling space for other stuff. I Checked out your thread, Nice tight framing work!! I am a carpenter by trade as well, after seeing those walls I know for sure you guys up in the great white north are keeping all the straight studs and sending us the twisted ones. Haha just kidding but I gotta ask, Is the price of wood as crazy up there as it is here? a 2x4x8 is going for almost $8 bucks here now, seriously considering buying a big tent for a veg room as it would be cheaper right now and I could use it again if I have to move. One last thing, How have you liked the Mr cool unit you have? Any problems or anything? Also really curious as to how the precharged lineset works? What do you do with the extra length? I am assuming the lineset has some sort of valves to keep the refrigerant inside so you cant cut it to length?

PS I LOVE those epoxy floors, I used the one part rustoleum epoxy from lowes when I first built this room last fall, was all I could afford and better than leaving them bare, but dang I cannot wait to lay some nice white 2 part glass in there after this next run. Yours look amazing and I am sure they look even better in person, What product did you go with?

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ah thanks! the framing on the ceiling was tricky for sure i wanted to create a separate building envelope for that room. im actually a red seal carpenter, the mr cool unit i haven't had any issues with it yet it works well can control it with a tv remote or your iphone. i ordered it on amazon can get it shipped right to your door. i liked the precharged line sets i didnt need to hire an hvac guy it was super easy that part. your right there is alot of extra length i just coiled it neatly on the bracket hanging on the wall behind the condenser. all you really need is two crescent wrenches, set of alen keys, and a can of thread sealant i think i used a brand called pro dope looks like a white paste. you just put the thread sealant on and tighten the two nuts together on each line. once that is done you take the alen key and gently open these two little valves and it pressurizes the system for you. the white epoxy i cant remember the name that was my first time doing two part epoxy i think i had to get it at a paint store since they had to tint it to get it the white color its super bright

If heights an issue maybe look into floor mount options, they’re pretty slick. I’m not familiar with those brands and if they have them or not, but Fujitsu halcyon has a nice floor unit (mounts 6” above the floor) has heat ac and dehumidify modes. If you’re in a basement spot a condensation pump. Sharp system, works well, I don’t know of any precharged linesets for DIY installs with these style heads but could be worth some research. My $.02

watsongreenthumb said:

Yeah I hear you, those 3 tons are heavy for sure, had to help lug a 3 ton unit up 3 flights of stairs and through a window onto a back roof years ago and I think my back still hurts. That might be the reason I seem to have some strange aversion to going bigger than 24k, since I will have to do the install mostly by myself. How did you like the pre charged linesets? I have never used those before how do they work exactly? do you think it was easier than just pulling a vacuum once you got everything hooked up/ would you go that route again? I have a 10" fan and filter combo that does a great job moving air around if its setup right, so I think I am going to go with a wall mount unit and save the ceiling space for other stuff. I Checked out your thread, Nice tight framing work!! I am a carpenter by trade as well, after seeing those walls I know for sure you guys up in the great white north are keeping all the straight studs and sending us the twisted ones. Haha just kidding but I gotta ask, Is the price of wood as crazy up there as it is here? a 2x4x8 is going for almost $8 bucks here now, seriously considering buying a big tent for a veg room as it would be cheaper right now and I could use it again if I have to move. One last thing, How have you liked the Mr cool unit you have? Any problems or anything? Also really curious as to how the precharged lineset works? What do you do with the extra length? I am assuming the lineset has some sort of valves to keep the refrigerant inside so you cant cut it to length?

PS I LOVE those epoxy floors, I used the one part rustoleum epoxy from lowes when I first built this room last fall, was all I could afford and better than leaving them bare, but dang I cannot wait to lay some nice white 2 part glass in there after this next run. Yours look amazing and I am sure they look even better in person, What product did you go with?

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I have 2 of the mr cool diy units and really like them. Install is super easy, if you can do electric. My one room is 12x24 and has 6 doubled ended 1k lights, so 6k watts, and it works great. The line sets are sealed and charged, the seal doesn’t break til you start to to tighten the nut on the line set. Only roll out enough lineset to reach and leave the rest rolled up, if possible try to mount loops of rolled up line horizontal instead of vertical, I didn’t and haven’t had any issues but have read since it’s better to keep them flat instead of up and down. I have installed 3 diy mini splits 2 mr cool and one off brand. The mr cool is a way better unit than off brand even though install was basically the same. The only thing I don’t like about mr cool is the company they sell thru, but luckily I found a hardware store that’s only an hour away that keeps them in stock.

I’ve installed several of the 3 tons units, the inside units can be a little bulky but are not that heavy, I am always able to carry them up a ladder and attach to bracket by myself. But I’m a tall guy with log arms.

Apalchen said:

I have 2 of the mr cool diy units and really like them. Install is super easy, if you can do electric. My one room is 12x24 and has 6 doubled ended 1k lights, so 6k watts, and it works great. The line sets are sealed and charged, the seal doesn’t break til you start to to tighten the nut on the line set. Only roll out enough lineset to reach and leave the rest rolled up, if possible try to mount loops of rolled up line horizontal instead of vertical, I didn’t and haven’t had any issues but have read since it’s better to keep them flat instead of up and down. I have installed 3 diy mini splits 2 mr cool and one off brand. The mr cool is a way better unit than off brand even though install was basically the same. The only thing I don’t like about mr cool is the company they sell thru, but luckily I found a hardware store that’s only an hour away that keeps them in stock.

I’ve installed several of the 3 tons units, the inside units can be a little bulky but are not that heavy, I am always able to carry them up a ladder and attach to bracket by myself. But I’m a tall guy with log arms.

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Thanks for the reply, sorry I have been totally swamped with work and battling a broad mite issue, so I hadnt logged on here in a couple weeks, but I went ahead and got the 24k C&H unit, mostly because I needed to be able to install it myself. However the outdoor condenser is huge for a 24k, at least as big and heavy as 3 ton units I have dealt with in the past. I guess the more efficient units get a lot of that efficiency through very large condensers (makes sense- more and bigger fins and fans give better heat transfer etc) but because of that I have had to wait to install it till this weekend when I could line up some help. Hopefully it will work out pretty well for me, since I am using more of the capacity it should dehumidify really well so that a plus I guess. Have not been in as much of a rush to get plants in the flower room as I have been battling broad mites in my veg area. That's been a total nightmare let me tell you, really fucked up my timeline for getting plants into my new space. I caught it really early so I have hope, they came in on a clone I got from a friend, I didnt have a totally separate area to quarantine it in but it was a good 5 feet away from my other plants, so even though the mites were not totally contained to that plant their numbers were very low in the other plants (saw one mite on the nearest plant in several hours of scoping with a decent Bluetooth adjustable zoom scope) so I think/hope I have a fighting chance.

SargentP said:

If heights an issue maybe look into floor mount options, they’re pretty slick. I’m not familiar with those brands and if they have them or not, but Fujitsu halcyon has a nice floor unit (mounts 6” above the floor) has heat ac and dehumidify modes. If you’re in a basement spot a condensation pump. Sharp system, works well, I don’t know of any precharged linesets for DIY installs with these style heads but could be worth some research. My $.02

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I looked at those, have used them in some construction projects, great in 3rd floor bedrooms with sloped ceilings/ dormers that limit available locations for a wall mount. Fujitsu makes great equipment but was out of my price range for this install, they would have been my first choice otherwise though. C&H does make a floor mount but it was a couple hundred bucks more for a much lower seer rating, also figured since I was going with a made in china sort of brand it was probably better to stick to the more standard wall unit. I have a vac pump and a good set of gauges, along with some other basic hvac tools so I didn't need the precharged lineset, for sure a lot more options if that isn't a necessity

xox said:

ah thanks! the framing on the ceiling was tricky for sure i wanted to create a separate building envelope for that room. im actually a red seal carpenter, the mr cool unit i haven't had any issues with it yet it works well can control it with a tv remote or your iphone. i ordered it on amazon can get it shipped right to your door. i liked the precharged line sets i didnt need to hire an hvac guy it was super easy that part. your right there is alot of extra length i just coiled it neatly on the bracket hanging on the wall behind the condenser. all you really need is two crescent wrenches, set of alen keys, and a can of thread sealant i think i used a brand called pro dope looks like a white paste. you just put the thread sealant on and tighten the two nuts together on each line. once that is done you take the alen key and gently open these two little valves and it pressurizes the system for you. the white epoxy i cant remember the name that was my first time doing two part epoxy i think i had to get it at a paint store since they had to tint it to get it the white color its super bright

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awesome man, I had to google red seal carpenters as we dont have that in the states, looks like its similar to our apprentice, journeyman, master carpenter system? I went with the C&H unit, uses a lot of the same parts as the mr cool but doesn't offer the precharged linesets. Figured I would save a little money since I have the tools and am comfortable pulling a vacuum on the system before I release the refrigerant. I use Nyloq for a thread sealant on hvac stuff, its a blue thread sealant that is probably pretty similar to the pro dope. Been battling a mite problem so I havent actually gotten to install it yet, other than running the wire for the outdoor disconnect, but I have someone to help me this weekend so planning get it installed then. Thanks for all your input, gave me some options to consider and really boosted my confidence in the Chinese made units based around the toshiba compressors.