12,000 btu enough for a sealed room?

I need help from the experts on this one. I have a 10x15 room with 4 1000w lamps going. The hoods are vented and the ballasts are in the room too. Right now i have no problem controlling the temp in the room. My problem is when summer hits i dont know how much a/c i need. Lights goes on at night but it gets hot during the day here and nights only go down to about 60-70 degrees. I was thinking about getting a 12,000btu split a/c turn off the exhaust fan for the room but keep the fans for the hoods on and run the room sealed. do you guys think 12,000btu is enough. I would run a bigger unit but that cant be done due to amp limit.

12,000 btu is a standard 3kw portable a/c these units are not that great to be honest, they work quite well to keep a standard size room cool in the summer
and this is in the UK lol its not that hot here, 90f outside in the summer
putting 4kw of light in a room , during summer and sealing the room with just a 12,000 btu does not sound good to me

one important thing to remember about a/c is that it recirculates air .. in order for ac to be efficient rooms are sealed so the air can be cooled
if you do not bring in new air directly from outside, or use co2, the air inside the sealed space will become dead co2 depleted air , this will cause lots of problems
so you still need to bring new air in .. which means the cold air from the a/c is getting sucked out, making it inefficient especially when a 12k ac uses 3kw

you could increase the size of your outlet and inlet fans, bring in air directly from outside that would help lower temps during summer
you could possibly run the ac and the extractor and inlet all on a control module so they work to allow new air to be brought in, then the extractor can turn off while the air is cooled , when that air becomes depleted of co2, the fans switch back on and bring new air in again

i have seen some folk, put ducting on the ac and feed it directly into the lights, this seems like an interesting idea , the extractor will suck from one end as the ac pushes cold air directly through the lights .. i think this could be the best option for a small ac
the cost of running ac, always makes me look for other solutions first

peace

Agree with the post above. You will need to either add Co2 or an active/passive air intake. Also, I am surprised you are not having heat issues right now with 4 1000w lights. I can only imagine that come summertime you will be running into bigger issues with heat. I do not believe a 12,000btu a/c is going to cut it. There are some general a/c sizing guideline you can follow.

120sq.ft x 40btu per. sq.ft. = 4,800btu
4kw of lighting x 4,000btu = 16,000btu
4 digital ballast x 2,500btu = 10,000btu
Dehumidifier x 30btu per Pint Rating = ??

These calculations are based on air cooled hoods being exhausted into the room. Every situation is different but I have to imagine that you will need at least a 24,000btu a/c. Changing out the breaker for that circuit and possibly replacing the wiring should not be a major issue and would allow you to apply more load on that circuit. Or; if this really is not an option you may want to look into either not sealing your room or purchasing a chiller to control temperature in the room.

unless you are in the desert,I will disagree w/ both of the above IF, you run CO2,the hoods are vented in & out of the room w/ decent fans & you move the ballasts to outside of the room. w/ CO2, you can run the room in the low 80s so unless your temps average in the upper 90s or better for most of the summer,you will be only trying to drop the temps 10-20 degrees from ambeint.
a larger unit will run more efficiently and cost less to run so if you can upgrade your electric for a reasonable price, it would be worth it to upgrade.

Running your lights at night is really going to help. Try and set your schedule for 7-7 or 8-8. That way you can avoid the late day heat that is around during the summer. The part that sucks is that you may not be able to test the unit before and see which one you need. Not really sure what your situation is but I am guessing since you are running 4k in lights that tearing it all down to install the a/c is not something you want to do twice (unless you are installing the a/c yourself). I still feel pretty confident that you are going to need a larger a/c than 12,000btu for a space that big with that many lights. You haven't mentioned anything about running Co2 or moving the ballasts out of the room. If those aren't options then I would think you would need a bigger a/c. I am also not sure if you have a dehu in the room but you will probably have to keep it in there. Mini splits aren't the best at dehumidifying but I don't know your situation. If you do have a dehu remember that they throw off heat as well.

i would def. get a bigger a/c then the one your thinking about....

I live in AZ and summer times are very hot close to 115-120 and i have 2 4x4 grow tents 600w Quantm ballasts. i use a 700cfm inline fan that i split so it pulls the air out of both tents and works very well. I also have a 6,500 btu window a/c unit that i have ducted directly to my 2 tents and it works great. but i would def try and figure out a way to vent all my hoods to outside the room and that will help you out 1000%

Thanks guys, the hoods are vented out of the room with a 800cfm and the room itself is vented with another 800cfm. I'm going to try to move the ballasts out of the room and i am going to use Co2. I already did all the electrical work to the house and i cant pull anymore amps out of the panel. So 12,000 is the highest i can go safely. On the dehumidifier, how can i calculate how big of a unit i need for my room size? I dont want to get one that overly big and add more heat to the room?

Good luck with the dehumidifier question.....I'll be watching that cause mine is hotter than my bank of ballasts. Shit is hot as fuck.

Also, I have a 14,000 btu dual hose Ac in my room, 3 x 1000 in an 8x12 space, and twin 400's in a space connecting, and another space with T5's, and my shit is 80.6 degrees right now, and it's 80 out. I can see the temp from my computer on a digital screen

Anyway, my room is obviousy sealed, nothing in or out, co2 on a controller, and it can get real warm in there in the summer. Plants do good though, but I'm about to order a chiller for my big res as the water gets too warm for my liking.

Good luck!!!!!

nowhere said:

Thanks guys, the hoods are vented out of the room with a 800cfm and the room itself is vented with another 800cfm. I'm going to try to move the ballasts out of the room and i am going to use Co2. I already did all the electrical work to the house and i cant pull anymore amps out of the panel. So 12,000 is the highest i can go safely. On the dehumidifier, how can i calculate how big of a unit i need for my room size? I dont want to get one that overly big and add more heat to the room?

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Why not just get a 240v a/c? You will be able to get twice the size with the same amount of amps. Just a though.

The a/c will handle some of the dehumidifying. My guess for a room that size without knowing your humidity levels is that a 40-50 pint should be just fine. Any dehumidifier blows out hot air, nothing you can do about it unless you buy a water cooled one or get an a/c unit big enough to handle the dehumidification and with seperate hygrometer/thermometer settings (that normally means air handler).

I would get as much equipment that generates heat out of the room! Pulling cool air from outside the room across the bulbs and out of the room will also help a lot. The more CFM's the better. Get a HO Max Fan. MOST fans falsely claim a higher CFM rating than you'll see. Look for the AMCA certification/rating!!

A/C will naturally lower the humidity. Also, you can choose a strain that is mold resistant along with several fans to keep the air circulating.

I think an 18k BTU would be fine. 24k BTU would allow you to hang meat in that room as well!!!

Check this out:

http://m.youtube.com/watch?v=cFS9kB_J-CA

24k mini split cools 4 thouies nicely,20amp 240 circuit though.

Ice box on your hoods and possibly one in the room. 8 inch ice box is 8500 btu depending on how cold you can chill your water. for a truly sealed room.

dbkick said:

Ice box on your hoods and possibly one in the room. 8 inch ice box is 8500 btu depending on how cold you can chill your water. for a truly sealed room.

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Might not be applicable in this situation. He would need 4 Ice Box (1 for each hood), a 1hp-1.5hp chiller, chiller reservoir, commercial pump, manifold lines, and he would still need an a/c in the room or another 2-3 Ice Boxes to act as a/c units which would mean probably a 2hp chiller. Total costs $5000+ easily.

+1.

I'm running an 18,000 btu mini-split with (4) 1000w in a sealed room, two-burner Sentinel CO2 generator, Frigidaire dehumidifier and still need more. Works better when I'm only running two of the 1000s. I'm thinking the 24k would be better for all four. I might even upgrade to a 36k mini-split with two blower units so I can put the other blower in an adjacent room, from where I pull all intake air.

phillipchristian said:

Might not be applicable in this situation. He would need 4 Ice Box (1 for each hood), a 1hp-1.5hp chiller, chiller reservoir, commercial pump, manifold lines, and he would still need an a/c in the room or another 2-3 Ice Boxes to act as a/c units which would mean probably a 2hp chiller. Total costs $5000+ easily.

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more like half that 2500 , He'd save that in cost running a split system that is a fraction as efficient as air cooled by chilled water. You can get 1/2 horse chillers with little use on them for 400 or so, this would bring the price down even more.

dbkick said:

more like half that 2500 , He'd save that in cost running a split system that is a fraction as efficient as air cooled by chilled water. You can get 1/2 horse chillers with little use on them for 400 or so, this would bring the price down even more.

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A 1/2hp chiller would only cool 2 lights, maybe 3 back to ambient room temps. He would still need to cool another 1-2 lights and the room itself. He would need 1/4hp of cooling for each light and then probably a 1/2hp for the room temps. You are correct that chillers are 40% more efficient than a/c but you aren't going to find a decent 1.5hp chiller for under $1000. EcoPlus has a 1.5hp one that is arounds $1100 but I wouldn't recommend that unit for this type of use. The components in those chillers are cheap and not meant for continuos use loads like this application. If he bought the Chillking one then he is looking at $2200. Then a good cast iton multi port pump 1/2hp pump is going to run him another $275. 6 Ice Box are going to run him $750. The reservoir, manifold lines, tubing, and fittings will be another $300-$400. Then he's need a fan temp controller the the Ice Box's he's using as a/c units. It's a lot more expensive than you think unless he buys everything used and does a bunch of DIY.

dbkick said:

more like half that 2500 , He'd save that in cost running a split system that is a fraction as efficient as air cooled by chilled water. You can get 1/2 horse chillers with little use on them for 400 or so, this would bring the price down even more.

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Read my signature thread. I've done more Water Cooled Grow Rooms than probably anyone on this site.

I did check your thread, but how is it you say that a chilled water coil is limited to 8500 btu, the size of the coil determines the max btu its capable of. You're quoting ice box btu . these are very small coils. Ah I see, you're talking about the ice box and ice flow. I guess everyone being able to do diy on something like this isn't really feasible but I work for a hvac shop, I can get evryting I need at like cost, a coil cost chump change, a housing costs nothing because I'd build it myself.