Need help with AC sizing

[fredtheman]

Hey guys new to this site. I have a current grow right now which is explained below but right now I have the money to buy 3 1000w standard mag ballast and 6 hoods. The ballast going to be run on a filp flop so six lights total. i plan on getting the supersun II reflectors because they are really slim and narrow so the flow of air will not be impeded as much as with wide reflectors. they have 6" flanges and running in a straight line with a Canfan 8" high output fan that puts out 737CFM. Does this sound good to you guys? To help i can get the sun shield reflector covers to prevent heat escape which i think i am getting a lot of with my big bulky radiant 6" AC reflectors that i have going now. Also my main question is how many btu's of cooling i will need for a 4'6" by 13' room with 3 air cooled 1000 watters??? will these ac work?

 

[Sunshinegrower]

Yeah I have wrote similar post about A/C sizing help, but no one have ever answered with factual info. I have been hearing it's around 4k Btu's per 1k light. You room depends on where you live, but most likely around another 4k Btu's. I would love to see what size of A/C people are running versus lights and Co2.

 

[RMCG]

3500 btu/1k + 20 btu /sq ft. for non air cooled is a decent rule of thumb.

 

[fredtheman]

Thanks guys is it significanly less if i use smaller hoods with heat shields to prevent heat build up and pull a lot of CFM across them? i want to oversize the AC so they will cool it down fast and only be on a short amount of time. I have heard those numbers before but was thinking it would be less with AC hoods so if i got a 10,000BTU AC for a 12X6 room with 3 aircooled hoods with 747CFM. It should not run very much all day, right? Also i want to seal the rooms so do will that AC I posted pull out the CO2?? Thanks

 

[RMCG]

Thanks guys is it significanly less if i use smaller hoods with heat shields to prevent heat build up and pull a lot of CFM across them? i want to oversize the AC so they will cool it down fast and only be on a short amount of time. I have heard those numbers before but was thinking it would be less with AC hoods so if i got a 10,000BTU AC for a 12X6 room with 3 aircooled hoods with 747CFM. It should not run very much all day, right? Also i want to seal the rooms so do will that AC I posted pull out the CO2?? Thanks

10k btu should do it. Don't oversize it too much as it will short-cycle.

 

[Sunshinegrower]

3500 btu/1k + 20 btu /sq ft. for non air cooled is a decent rule of thumb.

Hey man do you know a lot about HVAC? If I have two flower rooms, but only running one unit would a 2 Stage A/C work better?

 

[Midnight_son]

What do you mean by 2 stage? A split unit?

 

[RMCG]

Hey man do you know a lot about HVAC? If I have two flower rooms, but only running one unit would a 2 Stage A/C work better?

Room sizes? 2 stage? You can get multi-zone, mini-splits or ducts and dampers.

 

[Fred Flintstoned]

I run 5-600w without air cooling. I have a 17000btu window unit. It cools the room in August with no sweat!
The 4000 btu per 1000w lamp rule seems a little too small to me. I used to have a 10500btu unit trying to cool 1800w, it barely kept up.
Fred

 

[RMCG]

Was it an old unit? Needing a recharge? You are kind of cooling 'more' with 'less' with your 17k btu.

 

[Fred Flintstoned]

Good point, makes sense. That 10500 was new. POS Walmart special though.
This 17k is an LG. A little better quality. Though the thermostat is far from accurate.
Fred

 

[RMCG]

Good point, makes sense. That 10500 was new. POS Walmart special though.
This 17k is an LG. A little better quality. Though the thermostat is far from accurate.
Fred

One other thing, were the ballasts in the room or outside?

1k digis put out ~ 2500BTU over and above the bulbs.