Calculating The Size of a Air Conditioner

[00420]

But we seem to agree that the ballasts should go outside the room.

Ambient temp makes a HUUUGE difference... in winter, If the house got to around 65Fish , the (10K BTU portable) would do just fine, but that same set up with the house in the 80's and the AC would struggle.
I'd rather have too much AC, then not enough. But I guess it makes a difference wether you live in minnesota, or in arizona.

An undersized AC unit is teh suxxor.

i agree to disagree....

ballast should never go in a grow room if it can be helped..... BUT it should be "cooled" none the less........ heat is the reason caps go bad 75-80% of the time

the formula i have posted is to work with outside temps from 50-100 deg's if it gets cooler then 50 you dont need AC you need a pimp as fan how ever it will cool a room to 78-80 on them 115 days when i refer to ambient temp im talking about the room temp befor light. even if you live in minnesota im sure your house is 50-100 deg's not -35 like out side

 

[slipperysamus]

No air cooled hoods here, That would only require further heat and power consumption from the Dehu.

Digital Ballasts are WAY COOLER than the noisy old powerhouses... Mine dont have fans in them, and are in the room.

interior rooms with minimal ducting and insulation. Wall mount ACs are ducted from the outside of the room with a 1000cfm fan to aid cooling,

Ambient temps, anywhere from 50-105C ACs work more or less accordingly

 

[imnotcrazy]

105C ????? you live on Mercury??? lol

 

[DIGITALHIPPY]

No air cooled hoods here, That would only require further heat and power consumption from the Dehu.

Digital Ballasts are WAY COOLER than the noisy old powerhouses... Mine dont have fans in them, and are in the room.

interior rooms with minimal ducting and insulation. Wall mount ACs are ducted from the outside of the room with a 1000cfm fan to aid cooling,

Ambient temps, anywhere from 50-105C ACs work more or less accordingly

dude.... WHAT?????
how is it air-cooled hoods require more power??? i think you might have boinked you head on some sharp edge somewhere, maybe in that 122-221F heatwave u got.

 

[00420]

 

[mikecar312]

thanks for this post. great thread for people trying to get guidelines. seems like a lot of times beginners search for some sort of set of instructions or formula or just finding where to start when it comes to things like this. i know i was looking for something this when i first started.

IMO, experienced growers know that growing is not so much about formulas than it is about trial and error - you can read about it all you want but you don't know til you actually do it. everyone has different variables, not everything will work for everyone. Again, this is a great GUIDELINE.

No air cooled hoods here, That would only require further heat and power consumption from the Dehu.

this doesn't sound right to me. anyone else want to tell him he's wrong?

for all the beginners who don't want to do the math, my general guidelines are - air-cool all hoods, place the ballasts in another room (if possible), and buy the biggest a/c you can afford or a good intake/exhaust.

 

[seebobski]

ac bigger=better????

ac bigger=better????

bigger is not always better!!!


in a 300sq ft total volume of room (veg,flower and lung)
(hps ballast in lung room floro-ballasts in veg)
12000 btu ac 10.7 eer window shaker
400w floro's and
400w hps air cooled input air separated form grow - outside (filtered) then scrubbed and output - outside
room sealed with reflectic bubble insulation on inside walls,roof.

the ac will cycle on and off too much and lose of eer factor and it will not help dehumidify the grow or pg&e. from what I have found I am moving to a 6000 btu for my room. there is a point where you lose out if too big. there is a happy medium! we will see.

 

[OgreSeeker]

Awesome post 00420! I was getting really tired of seeing those "how big" questions!


seebobski,
Correct.
Bigger is usually better but not always. Like using a 24,000btu unit in a minicab

 

[00420]

this doesn't sound right to me. anyone else want to tell him he's wrong?

i wont say it's wrong but it dont sound right....
at the same time this dont either

experienced growers know that growing is not so much about formulas than it is about trial and error

or this

for all the beginners who don't want to do the math, my general guidelines are - air-cool all hoods, place the ballasts in another room (if possible), and buy the biggest a/c you can afford or a good intake/exhaust.

if the ballast is not cooled you will have caps going bad on you
here is my 2nd line on the thread.....

with this formula a room would be able to get in the 70-72 deg range even when it's 100+ but yet still maintain humidity at night time with proper air movement

SEEBOBSKI is 100% on this....

bigger is not always better!!!

in a 300sq ft total volume of room (veg,flower and lung)
(hps ballast in lung room floro-ballasts in veg)
12000 btu ac 10.7 eer window shaker
400w floro's and
400w hps air cooled input air separated form grow - outside (filtered) then scrubbed and output - outside
room sealed with reflectic bubble insulation on inside walls,roof.

the ac will cycle on and off too much and lose of eer factor and it will not help dehumidify the grow or pg&e. from what I have found I am moving to a 6000 btu for my room. there is a point where you lose out if too big. there is a happy medium! we will see.

btw thx for bringing intake/exhaust into this.... i added some things about it to the top post mikecar312, we all agree to disagree on everything except that this is a guideline

Awesome post 00420! I was getting really tired of seeing those "how big" questions!


seebobski,
Correct.
Bigger is usually better but not always. Like using a 24,000btu unit in a minicab

my 2nd grow room was 8 x 10 x 9..... i put a 25,000 btu in there (2k) let me tell you......BIG BUD'S everywhere...... so much mold even with a 65 pint dehu it was sad....... thats when i learned bigger is not better....

 

[samba]

the reason i dont put my ballasts out of the room ( btw i run 8 ballast on flip flop's 4 in each room) is theres no other place to put them i have a huge room with 4 rooms built in that.... any place i put them there in a growroom...

What if you had the ballast in the other flipflop room? That way the ballast would be heating the room with no light on thats cooler anyway... Might not work with you ventilation setup, just an idea...

And THANKS a MILLION for a GREAT thread

 

[00420]

What if you had the ballast in the other flipflop room? That way the ballast would be heating the room with no light on thats cooler anyway... Might not work with you ventilation setup, just an idea...

And THANKS a MILLION for a GREAT thread

i had 8 ballast 4 in each room so the heat is even in the 2 flowering rooms...
if i put it out of the room it would be in my mom/clone room. i have all so ran a 10k flip flop 10k in garage flop'd to 5k in 2 bedrooms in this house the ballast where placed in the wash room cooled from the house a/c either way your still cooling your ballast.... and should be.

i dont really use ventilation just a/c its too hot 75% of the yr where i live

 

[DieselFuel]

A little help 00420, if you don't mind..

Room Specs: 10x4x8, Double layer of R19 in the ceiling and walls, 1" thick drywall all around with a layer of panda plastic lining the room. (60 plant sog in there as well)

Equipment: 1x 1000w, 10k btu a/c, and a 65pt. dehuey

The problem is.. both the a/c and especially the dehuey is kicking on and off constantly... I have the a/c set to 78 right now, should I set the temps lower to combat this problem? (You did say the goal is to keep the a/c running constantly during lights on ,correct?)

Sorry for rambling.. but the problem for me is getting the humidity under control.. with the dehumidifier set to 55% my gauges are still reading about 64%. I would absolutely love it if you could offer some solutions. Thanks for any help (First time running a sealed room.. sorry for being an hvac noob)

btw, the a/c has a cool mode and a dry mode on it. According to the manual, dry mode runs the compressor at half the power and then completely shuts off when the room cools. Cool mode runs at full power and leaves the fans running when it isn't blowing cold air.. any suggestions of which one I should use?

 

[00420]

A little help 00420, if you don't mind..

Room Specs: 10x4x8, Double layer of R19 in the ceiling and walls, 1" thick drywall all around with a layer of panda plastic lining the room. (60 plant sog in there as well)

Equipment: 1x 1000w, 10k btu a/c, and a 65pt. dehuey

The problem is.. both the a/c and especially the dehuey is kicking on and off constantly... I have the a/c set to 78 right now, should I set the temps lower to combat this problem? (You did say the goal is to keep the a/c running constantly during lights on ,correct?)

Sorry for rambling.. but the problem for me is getting the humidity under control.. with the dehumidifier set to 55% my gauges are still reading about 64%. I would absolutely love it if you could offer some solutions. Thanks for any help (First time running a sealed room.. sorry for being an hvac noob)

btw, the a/c has a cool mode and a dry mode on it. According to the manual, dry mode runs the compressor at half the power and then completely shuts off when the room cools. Cool mode runs at full power and leaves the fans running when it isn't blowing cold air.. any suggestions of which one I should use?

for that size room with 1k.... you would only need around 6500 but was a good idea getting a 10,000 so you can add a 2nd 1k later id suggest running in dry mode & "low or 1" fan speed more then likely your running it on "high or 3" most ppl run there a/c on "high or 3" for the fact it cools faster. i like to keep mine on 2 that way on the cooler winter nights you can put it on 1 (low) and on the hot summer days you can kick it up to 3 ( high )

being in dry mode and low fan speed it will cost you less by running more ( sounds funny ) but its true..... it should all so make your dehu run less witch in the end means less heat

 

[THCV]

very useful thread, thanks 00420. here's something that i didn't see mentioned: running lights at night to take advantage of cool night air. For me, it has made a "night and day" difference in terms of the btus needed per 1K. I only run my 12 or 18 hours in the coldest/darkest hours of the day. Any idea what the math would be for running day vs night?

Also, the new spot i am setting is a basement with one side embedded in a hill, and the other side exposed to sun for part of the day (which will be fully insulated and painted white). How much of a heat-sink effect have people noticed in basement setups? Does the ground help cool significantly?

I am hoping to fire up 8KW total, but am planning to start smaller with 3K and a burner for veg and an 18KBTU windowshaker. All lights will be aircooled with cool night air. I'll upgrade AC as i go along, but after reading this i am wondering if 18K is too small to begin with. I guess I'll try is and see.

 

[DEDHEDFRED]

Hey THCV.........Hope all`s been well in your lil corner of tha world......Lotta good info in this thread 00420........Thanks for your input.........I`ve always worked off the 4000 btu`s per 1000 watter but that was bare bulbs not air-cooled when I was runnin krusty buckets........I only grow in basements now and use a lung room of sorts to bring air in and out of the flip rooms with temps in the high 50`s during winter and maybe high 60`s in summer with fresh air pulled outta the crawlspaces mixed in with the big room but I only run 3-600`s per room so my a/c`s and dehueys never haveta work overtime due to major air exchange with active intakes and exhausts out thru scrubbers........Thanks again 00420..........Peace.........DHF........ .....

 

[DieselFuel]

Thank you 00420

 

[dark_ronin]

is a 5000 btu wall unit enough to cool this room:
1 1k hanging vertically (bare-bulb; no cool tube/ded vent for light)
4'x4'x4' insulated cab?

 

[MR.GreenTacos]

there are some other factors to remember also ,i work in the HVAC trade .U guys have some NEAT numbers! basisc 12,000 btu = 1TON of cooling ac, rule of thumb is 1ton for every 400 sq ft then how insulated the area is so u can factor heat transfer also a 12,000 btu wall unit dosen't cool the same area as other styles of ac's.I'm not a pro at growing a garden,my experience come from handling the cooling and ventilation of progects with a friend now he has passed and and i'm on my own trying to learn as fast as I can.anybody who has any serious tech ?'s or problems with there ac's, fans whatever I will glad to help fix it best i can i have tons of info on how to keep elec bills very small without stealing elec or a heat issue.

 

[ooga booga]

I'll be rocking a 14,500 BTU window unit (@ 10.7 EER) in my new 6000w sealed room, two Vortex 8" cooling lights. Room inside a basement room, on the inside room 3 of 4 walls insulated with R-13, 1 wall insulated with R-19. Cement floor.

Hope that's enough; I'll report back in a week or so and see how it goes.

 

[Befri]

Need some help here:

I have been struggling with a heat issue in my sealed room. Here are the stats:
Basement style grow room 12'x8'x6'8"
I split this room into a VEG(7x8) and flower(5x8)

Veg is T-5 432watt light

Flower is 2-1k air cooled lights(sealed hoods with cool air and exhausting outside the room)

The way my basement was sent up(game room) the a/c that was already there(wall mount 6M btu). So I keep the a/c there and tried to use it. The flower and veg room have 2-6" fans transferring air between each other with a scrubber between the two. So my original thought was to run the 6M btu a/c to try and cool both rooms. That didn't work...the veg stayed ok at 75F but the flower stayed around 90-92F. SO then I went and bought a 15M btu a/c(wall mount) to hang in the flower room. After putting it in....it looked to big. But I figured that I needed the "big" a/c. Well the a/c cycles on and off with both rooms still exchanging air between them two. The only way I can get the rooms to stay stable is run the 15M and the little 6M in both rooms. The reason why is the BIG DOG a/c wont stay on long enough to cool the rooms down. I do have the a/c on low(speed 1) and still no help!

If I did the formula on this thread and adding up all the components between both rooms I'm at 10625 BTU needed. Now that is not counting the DH if needed. I would think the a/c would take care of that. If not I have a 65pint DH on hand if needed.

So should I take the 15M a/c back and get the 12M Btu??

Will I ever get both rooms to stay somewhat stable in the ideal temps??