hvac advice on btu's for room

GreenGalaxyFarm · Feb 5, 2023

any knowledgeable hvac peeps out there that can help me determine the btu required per plant, growing 24 plants in a 188sqft space. bought one that popped up on the classifieds in my area and had it dropped off, my calculations on it works out at close to 600 btu per plant, if that's even the correct measurement in this case. would rather be conserving on cost of electricity as this unit runs at max 1650w/7.5a/240v/50hz. any advice and recommendations welcome. this will work in conjunction with a 12l/3.17gal dehumidifier.

on a less pressing issue, is with selecting a oxygen concentrator air and water unit. do these function in the same way as running co2 with regulator. i'm assuming with these you would just go with the biggest you can afford to invest? lights would be run at 1150ppfd during its peak at flower and i'm planning to adjust other parameter as the grow progresses. not sure what all to take into account, apologies for the long read if you found it boring. lastly, i'll admit that i'm aware of the fact that this is asking for free consulting, but im cheap like that

Anthem · Feb 5, 2023

GreenGalaxyFarm said:
any knowledgeable hvac peeps out there that can help me determine the btu required per plant, growing 24 plants in a 188sqft space. bought one that popped up on the classifieds in my area and had it dropped off, my calculations on it works out at close to 600 btu per plants, if that's even the correct measurement in this case. would rather be conserving on cost of electricity as this unit runs at max 1650w/7.5a/240v/50hz. any advice and recommendations welcome. this will work in conjunction with a 12l/3.17gal dehumidifier.

on a less pressing issue, is with selecting a oxygen concentrator air and water unit. do these function in the same way as running co2 with regulator. i'm assuming with these you would just go with the biggest you can afford to invest? lights would be run at 1150ppfd during its peak at flower and i'm planning to adjust other parameter as the grow progresses. not sure what all to take into account, apologies for the long read if you found it boring. lastly, i'll admit that i'm aware of the fact that this is asking for free consulting, but im cheap like that

You need to consider the lights being used. Hawthorne gardening has a calculator you can use. With a 640 watt LED like a Spyder 2i or Gavita 1700e I always used 3000 BTU's per plant. Running bottled CO2 and no oxygen generators. Also you have to consider how well the place is insulated. I had a setup so well insulted and sealed up the CO2 would get up to about 2400 parts per million towards the end of lights out. More than just simple math and more is better to a point. You want the equipment to run and not do the short run and shoot off because that creates too much of a swing in parameters. I really like to run 2 AC units per room. One is always running and gets the shit beat out of it, the other is set at a higher temperature so it only comes on a couple times with lights on.

Anthem · Feb 5, 2023

Anthem said:
You need to consider the lights being used. Hawthorne gardening has a calculator you can use. With a 640 watt LED like a Spyder 2i or Gavita 1700e I always used 3000 BTU's per plant. Running bottled CO2 and no oxygen generators. Also you have to consider how well the place is insulated. I had a setup so well insulted and sealed up the CO2 would get up to about 2400 parts per million towards the end of lights out. More than just simple math and more is better to a point. You want the equipment to run and not do the short run and shoot off because that creates too much of a swing in parameters. I really like to run 2 AC units per room. One is always running and gets the shit beat out of it, the other is set at a higher temperature so it only comes on a couple times with lights on.

Excuse me 3000 BTUs per light

GreenGalaxyFarm · Feb 5, 2023

thank you for your consideration, ill try to provide additional information as best i can.

Anthem said:
You need to consider the lights being used.

these will be either 6x lumii 690w led(with little to no farred)on 30w drivers, or 6x 690w lumii black digitals(my preferred spectrum) on boost with manufacturers recommended bulb. a lesson on hps against led lighting released recently by debacco university confirms my preference to go with the hps. i should explain that i can do better with 1000w hps im aware but do not have the ceiling height in that room.

Anthem said:
Gavita 1700e I always used 3000 BTU's per plant.

did you find the increase in yield to justify running hvac at this intensity.

Anthem said:
Running bottled CO2 and no oxygen generators.

are you opposed to oxygen generators or do you find co2 to be tried and trusted and tend to stick with it for that reason?

Anthem said:
Also you have to consider how well the place is insulated.

double brick and mortar [(90mm x120mm)brick size, 240mm total wall thickness after mortars added)]
100mm insulation in the ceiling with 2 passive intakes and 2 outlets, also passive. though i might have to convert these vents to active when the peak temps come next summer.

Anthem said:
I had a setup so well insulted and sealed up the CO2

yes sealed.

Anthem said:
would get up to about 2400 parts per million towards the end of lights out.

im getting a ton of conflicting information on this in regards to ppm specifically and have been advised by my hydro guy to stick with 1200-1400 running 690w hps.

Anthem said:
More than just simple math and more is better to a point. You want the equipment to run and not do the short run and shoot off because that creates too much of a swing in parameters. I really like to run 2 AC units per room. One is always running and gets the shit beat out of it, the other is set at a higher temperature so it only comes on a couple times with lights on.

you recommend a specific controller for hvac or trust the built in unit to work fine?

GreenGalaxyFarm · Feb 5, 2023

Anthem said:
Excuse me 3000 BTUs per light

ill run the math..
puts us at 750 btu per plant.
so i would need a 1800btu unit on the opposite end of the room, is my thinking correct?

edit: so my options from one supplier carrying portable versions have 7000btu unit as the minimum (https://www.takealot.com/gmc-aircon-7-000-btu-portable-airconditioner/PLID73021373). but they also list an 80w evaporative air cooler (https://www.takealot.com/bomaster-evaporative-air-cooler/PLID70963035) are these worth looking into, seems they are highly rated.

Anthem · Feb 5, 2023

GreenGalaxyFarm said:
thank you for your consideration, ill try to provide additional information as best i can.

these will be either 6x lumii 690w led(with little to no farred)on 30w drivers, or 6x 690w lumii black digitals(my preferred spectrum) on boost with manufacturers recommended bulb. a lesson on hps against led lighting released recently by debacco university confirms my preference to go with the hps. i should explain that i can do better with 1000w hps im aware but do not have the ceiling height in that room.

did you find the increase in yield to justify running hvac at this intensity.

are you opposed to oxygen generators or do you find co2 to be tried and trusted and tend to stick with it for that reason?

double brick and mortar [(90mm x120mm)brick size, 240mm total wall thickness after mortars added)]
100mm insulation in the ceiling with 2 passive intakes and 2 outlets, also passive. though i might have to convert these vents to active when the peak temps come next summer.

yes sealed.

im getting a ton of conflicting information on this in regards to ppm specifically and have been advised by my hydro guy to stick with 1200-1400 running 690w hps.

you recommend a specific controller for hvac or trust the built in unit to work fine?

GreenGalaxyFarm said:
ill run the math..
puts us at 750 btu per plant.
so i would need a 1800btu unit on the opposite end of the room, is my thinking correct?

You will have to do the math for your lights but that is going to create a higher heat load than the LED's from what I have seen.
The HVAC numbers are based on my experience with multiple grow rooms set up but again I use nothing but LED's based on DR, Bruce's research and electricity is expense in my area so any additional yield from HPS is going to be off set by electricity cost of HPS and Bulb Cost. I use a quantum sensor and the bulb go bad. Plants give off CO2 when the lights are off, hence the high CO2 at lights off. I run 1450 lights on.
Your grow room is a problem with the walls and ceilings. Your ceiling is basically R-13 insulation. I would like to see R-30 and your walls are a huge problem. Your walls can be a problem because they work opposite of the time of day because of the make up. They heat up at peck temperatures and give off heat at low temperatures. I would probably consider lining the whole room with 2" Polyurethane foam board or at least polystyrene.
6 HPS lights shooting from the gut are going to need about around 4 tons of AC. So about 48000 BTU's. But use the Hawthorne Calculator I described. Also there is a search engine up at the top left of the main screen. There you can search by persons name. I will look up the guys name but his build out will help you. back what another post is a few.

Anthem · Feb 5, 2023

Well at some point in the last 6 months or so they removed the content from about 8 years ago which is where I was going to send you.

Anthem · Feb 5, 2023

I tried again and the older folks on here do not auto populate when you do a search for their name. The guy I was looking for is Gettogrow or something like that. I have tried to find his thread but the search engine only does a 10 page search and it did not come up. It was about 10 year ago but the tech is current for what you are trying to do.

GreenGalaxyFarm · Feb 5, 2023

Anthem said:
The HVAC numbers are based on my experience with multiple grow rooms set up but again I use nothing but LED's based on DR, Bruce's research

can you link me up to that article. best i can do is go 4 hps 2 leds and run comparison on lighting as a side project but there is no way i can do all 6 led. at least not during the first few cycles.

Anthem said:
and electricity is expense in my area so any additional yield from HPS is going to be off set by electricity cost of HPS and Bulb Cost.

a true consideration that applies strong to my situation, as i need to run petrol generators during power cuts. ive worked out on runtime for the specific unit to be 8hours running either led or hps?maybe i fckd up during calculations. i dont have anyone to fact check my figures. bulb cost isnt an issue and are readily available. the lumii reflectors as well come well in abundance here and will be replaced yearly.

Anthem said:
Your ceiling is basically R-13 insulation. I would like to see R-30 and your walls are a huge problem. Your walls can be a problem because they work opposite of the time of day because of the make up. They heat up at peck temperatures and give off heat at low temperatures. I would probably consider lining the whole room with 2" Polyurethane foam board or at least polystyrene.

as i read the start op paragraph i started to consider those poly boards/or poly panels as a means of further insulation.
would i simply have to add insulation on top of the 100mm currently installed to achieve R-30?

Anthem said:
6 HPS lights shooting from the gut are going to need about around 4 tons of AC. So about 48000 BTU's.

out of my budget.

Anthem said:
But use the Hawthorne Calculator I described.

im opening yet another tab..thanks

Anthem said:
Also there is a search engine up at the top left of the main screen. There you can search by persons name. I will look up the guys name but his build out will help you. back what another post is a few.

my brother

Anthem · Feb 5, 2023

GreenGalaxyFarm said:
can you link me up to that article. best i can do is go 4 hps 2 leds and run comparison on lighting as a side project but there is no way i can do all 6 led. at least not during the first few cycles.

a true consideration that applies strong to my situation, as i need to run petrol generators during power cuts. ive worked out on runtime for the specific unit to be 8hours running either led or hps?maybe i fckd up during calculations. i dont have anyone to fact check my figures. bulb cost isnt an issue and are readily available. the lumii reflectors as well come well in abundance here and will be replaced yearly.

as i read the start op paragraph i started to consider those poly boards/or poly panels as a means of further insulation.
would i simply have to add insulation on top of the 100mm currently installed to achieve R-30?

out of my budget.

im opening yet another tab..thanks

my brother

That is it for me. If you want to start paying someone to set it up that might be your best bet. Sorry man I got work to get done of my own.

GreenGalaxyFarm · Feb 5, 2023

Anthem said:
I tried again and the older folks on here do not auto populate when you do a search for their name. The guy I was looking for is Gettogrow or something like that. I have tried to find his thread but the search engine only does a 10 page search and it did not come up. It was about 10 year ago but the tech is current for what you are trying to do.

im finding getogrow on trollitup, maybe something there?

GreenGalaxyFarm · Feb 5, 2023

Anthem said:
That is it for me. If you want to start paying someone to set it up that might be your best bet. Sorry man I got work to get done of my own.

no your help has been greatly appreciated and will be instrumental towards the success of this and future grows.
ill make some calls to freelance consultants come monday morning. this information if at the very least will allow me to not sound like a complete moron with my lack of knowledge at indoor growing in a hydro setup.

Anthem · Feb 5, 2023

GreenGalaxyFarm said:
im finding getogrow on trollitup, maybe something there?

Are his posts like 10 years old?

GreenGalaxyFarm · Feb 5, 2023

Anthem said:
Are his posts like 10 years old?

he's been on their since '08

Anthem · Feb 5, 2023

GreenGalaxyFarm said:
he's been on their since '08

You can look up his posts but I am pretty sure it started with getto. Got to get to work on the garden now

GreenGalaxyFarm · Feb 5, 2023

135mm of thermal insulation gives me an extra 3.38 ''points'' in R-Value. That in addition to the 100mm currently up there, add up to a combined value of R 5.88 (3.38+2.5). 60usd delivered.
additionally, polystyrene panels for the walls and windows(double lined) amounts to around 305usd delivered of 45mm thickness board. the addition to R-Value unknown. i'm going with anthems suggestion regarding these board with 45mm being the thickest i could find in my area.

GreenGalaxyFarm · Feb 5, 2023

it has become evident to me that i need to remove the rhinoboard ceiling panels adding to the overall height and sq footage. creating ease of access for installation of ducting and mainatance of duct fans. painting the roof white has also come up.
this video seems to be adding very appropriate information on running parameters, in the hvac space.
link :https://www.youtube.com/watch?v=QBfitrF4H2Y

smokedareefer · Feb 5, 2023

gettogro

gettogro on THCFarmer.

www.thcfarmer.com

GreenGalaxyFarm · Feb 5, 2023

smokedareefer said:
gettogro

gettogro on THCFarmer.

www.thcfarmer.com

this is interesting and maybe efficient at its time i am going to need to be dialing in all sorts of other parameters than gettogro to achieve my desired results, it being a converted outhouse, and for example medium would be hydroponic [42 plants (12/row)] will allow unlimited potential for root growth during the time in the tubes. and lighting 1000w hps, with hood type reflector connected to the exhaust ducting

Anthem · Feb 5, 2023

GreenGalaxyFarm said:
it has become evident to me that i need to remove the rhinoboard ceiling panels adding to the overall height and sq footage. creating ease of access for installation of ducting and mainatance of duct fans. painting the roof white has also come up.
this video seems to be adding very appropriate information on running parameters, in the hvac space.
link :https://www.youtube.com/watch?v=QBfitrF4H2Y

The more dialed in you want your parameters the costly the build out becomes. just saw the first 10 seconds of the video you posted and that is cool but you are going to have to consider your budget. Just the HVAC in the start of the video is about 5 times the cost of a small mini split. That is where mechanical gets expense with VAV's and air handling units. So while gettogro might have had some stuff that was not perfect it comes down to what someone can afford.

hvac advice on btu's for room

hvac advice on btu's for room

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