9000 or 12000 btu

I am building new room and will be splitting it in half. One side for veg 5'x10', other side for bloom 6'x10' both 9' high. Bloom side running (2) 1000w HPS 6" raptors on track movers, veg side (1) 1000 MH 6" raptor on track mover with 2x4 EnviroGro FLT48 for pups. This room is sealed like a drum so I will be adding CO2 via Titan Atlas 2. My understanding is CO2 requires higher room temp (85 deg) at all stages to be effective. I am building a fan rig for hoods but it wont be exhausting out, just expelling hot air up (90 deg). My thoughts are 9k btu ductless for veg will suffice and 12k for bloom but I am reading 12k is the norm for this setup. Anyone have working knowledge on this one? Thanks,

willydriller said:

I am building new room and will be splitting it in half. One side for veg 5'x10', other side for bloom 6'x10' both 9' high. Bloom side running (2) 1000w HPS 6" raptors on track movers, veg side (1) 1000 MH 6" raptor on track mover with 2x4 EnviroGro FLT48 for pups. This room is sealed like a drum so I will be adding CO2 via Titan Atlas 2. My understanding is CO2 requires higher room temp (85 deg) at all stages to be effective. I am building a fan rig for hoods but it wont be exhausting out, just expelling hot air up (90 deg). My thoughts are 9k btu ductless for veg will suffice and 12k for bloom but I am reading 12k is the norm for this setup. Anyone have working knowledge on this one? Thanks,

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I had no problem with a 4k room, air cooled hoods vented from outside the room, a 720cfm scrubber, and a 10000btu a/c. my space was 10x12x8 and my heat rarely reached 82F

Thanks marquez, were you running a ductless or portable or window shaker?

Window Shaker, Cost me 60usd at a pawn shop brand new. I like the ductless, best for the money IMO.

will most likely go 12k btu in both rooms. As I was writing this post I resolved that its better to have the extra balls in the AC and not need it than to need it and not have it. This shit is starting to add up $$$

willydriller said:

will most likely go 12k btu in both rooms. As I was writing this post I resolved that its better to have the extra balls in the AC and not need it than to need it and not have it. This shit is starting to add up $$$

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Ye man, consider the wattage use and gram per watt. Grow some dank in your awesome room, cause your paying for the experience either way!

Over efficiency is the trick. You will save money by having a over efficient system. The 12K will run less then the 9K trying to keep up.

marquezmurder said:

I had no problem with a 4k room, air cooled hoods vented from outside the room, a 720cfm scrubber, and a 10000btu a/c. my space was 10x12x8 and my heat rarely reached 82F

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Outside temps, humidity, growing techniques, flooring and co2 play a huge part of different possibilities, please be more descriptive.

willydriller said:

will most likely go 12k btu in both rooms. As I was writing this post I resolved that its better to have the extra balls in the AC and not need it than to need it and not have it. This shit is starting to add up $$$

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Hey bro buts it's definitely worth it..

Definitely the bigger the AC the better as some others have said it will run less/more efficiently. As a general rule of thumb when I am calculating AC size for my rooms I use 4000 btu for every air-cooled 1000w light. That is a minimum baseline number though. It works fine for me using a co2 burner and in 100+ degree weather in the summer.

How well your room is insulated and the size of the fan cooling your lights will play a part in it too though. Going 5-6000 btu per light certainly doesn't hurt

ODanksta said:

Outside temps, humidity, growing techniques, flooring and co2 play a huge part of different possibilities, please be more descriptive.

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Second story, outside temps up to 80, my lung room was a constant 70degrees. My humidity was around 32%. This is on the second story of a house. All my ventilation runs to the attic. As for Co2, I didnt use any since I lived in the same room. This was a Polytarp Indoor grow room I made using my greehouse know how. Grow methods, well i experimented... check out my signature.

Nice setup marques, This room is sealed like a drum so I should be able to tweak the environment as needed +/- temp and humidity as well as CO2 levels. I get 6 clones already rooted next week and will hit the switch on the room in 3 weeks. Have decided on 12k for both sides just in case I fill both sides up with flowering plants at some point. The rooms are divided by 8' sliding glass doors (glass painted white) so I can pull them out if needed and go 10x12 with 24k btu and 4k lights. Nice to have options

Outside temps, humidity, growing techniques, flooring and co2 play a huge part of different possibilities, please be more descriptive.

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Its hot as fuck here and humid as well. The room I built is completely sealed with a vapor barrier over r13 and under 1/2 drywall painted. It can be 95 deg outside and the room is low 80's.

willydriller said:

This shit is starting to add up $$$

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Get used to it

707humboldt said:

Definitely the bigger the AC the better as some others have said it will run less/more efficiently. As a general rule of thumb when I am calculating AC size for my rooms I use 4000 btu for every air-cooled 1000w light. That is a minimum baseline number though. It works fine for me using a co2 burner and in 100+ degree weather in the summer.

How well your room is insulated and the size of the fan cooling your lights will play a part in it too though. Going 5-6000 btu per light certainly doesn't hurt

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A A/C running nearly constantly is more efficient. It also dehumidifies better.

Yea, I am becoming MacGyver in order to save $ where I can. Rigging up a cooling fan solution for hoods for under $20. Will post when complete and tested.(providing it works)

Red1966 said:

A A/C running nearly constantly is more efficient. It also dehumidifies better.

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How does an AC running constantly run more efficiently? I was in the HVAC world for a while, you want the AC/Heat not to run constantly. Thats what differentials are for, for example you cool it to 76 and then the room will heat up to 78 before it kicks back on again so it doesn't run constantly. Goes the same way with heat. If it runs constantly you are using more power which makes it less efficient which equals higher power usage and cost. It will dehumidify better because it would be running constantly but you need dehums for any large room regardless so that wouldn't matter.

willydriller said:

I am building new room and will be splitting it in half. One side for veg 5'x10', other side for bloom 6'x10' both 9' high. Bloom side running (2) 1000w HPS 6" raptors on track movers, veg side (1) 1000 MH 6" raptor on track mover with 2x4 EnviroGro FLT48 for pups. This room is sealed like a drum so I will be adding CO2 via Titan Atlas 2. My understanding is CO2 requires higher room temp (85 deg) at all stages to be effective. I am building a fan rig for hoods but it wont be exhausting out, just expelling hot air up (90 deg). My thoughts are 9k btu ductless for veg will suffice and 12k for bloom but I am reading 12k is the norm for this setup. Anyone have working knowledge on this one? Thanks,

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Just a suggestion, if it were my room I would go with the raptor 8s instead of 6s. I love raptors, I use to use them in all my rooms before I upgraded to DE. That extra 2" in diameter really gives a good amount of extra air flow and removes the heat better.

707humboldt said:

How does an AC running constantly run more efficiently? I was in the HVAC world for a while, you want the AC/Heat not to run constantly. Thats what differentials are for, for example you cool it to 76 and then the room will heat up to 78 before it kicks back on again so it doesn't run constantly. Goes the same way with heat. If it runs constantly you are using more power which makes it less efficient which equals higher power usage and cost. It will dehumidify better because it would be running constantly but you need dehums for any large room regardless so that wouldn't matter.

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You ever install a modern unit? They have variable speed compressors (at double the cost or more) just so they can run constantly. The differential is so the unit just run forever, freezing the room. Constantly running a smaller unit is more efficient than stopping and starting a bigger unit. Time isn't the only factor in energy usage. Draw is just as important. Dehumidifying

707humboldt said:

It will dehumidify better because it would be running constantly but you need dehums for any large room regardless so that wouldn't matter.

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Dehumidifying less than needed most certainly does matter

Red1966 said:

You ever install a modern unit? They have variable speed compressors (at double the cost or more) just so they can run constantly. The differential is so the unit just run forever, freezing the room. Constantly running a smaller unit is more efficient than stopping and starting a bigger unit. Time isn't the only factor in energy usage. Draw is just as important. Dehumidifying

Dehumidifying less than needed most certainly does matter

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The variable speed can go both ways, a larger unit can work at half speed rather than a smaller unit running full speed trying to keep up. A 12000 btu AC running at 70% is more efficient than a 9000 running at 100%.

1 hour X 12000 / 20 seer (just as a base number) X .7 (70%) = 420W
1 hour X 9000 / 20 seer @ 100% = 450w
Just an example, this equation works for variable speed or a unit turning on/off

All I was saying is that its always better to get the larger unit to make sure that it keeps up, last thing you want is a unit that has to fight to barley keep it at the temperature you want. Or it isn't able to keep it cool on days when its 100+ mid summer. Its a lot better to be able to have it keep it at whatever temperature you want easily.

My dehums rarely run when the lights are on, maybe they might kick on for an hour on a water day when the rooms are in full on flower and the plants are putting off a bunch moisture. 99% of the time they run while the lights are off and the humidity jumps.