Originally Posted by ninfan77

How would one justify the running of a window or mini split A/C in the winter time..... Wouldn't it freeze up?

I've been debating using a small ac in my grow room exhausted into the rest of my house. Capture the leftover heat.
ET

[superultramega]

My a/c actually exhausts inside the building.
I tore open a window unit and created a sealed evaporator coil ducted back into the grow completely sealed.
Of course you need a decent amount of space to exhaust into, but this can be achieved in multiple ways. It would work great in a basement.
Odor is a concern for me so I need to run an exhaust to keep a negative pressure on the room. You can never stop all the pinhole leaks. And pinhole leaks is all it takes. As far as running both it isn't a problem if your room temp is higher than the temp of your intake air. It simply helps out the cooling. You are venting conditioned air, but it is getting replaced with air cooler than your room. There is no efficiency loos for your a/c.
With my setup where the a/c exhausts inside the building and my fresh air intake is in the building which always has conditioned air, the only loss is from the main a/c unit for the building, but I haven't noticed it to be an issue significant enough to worry about. It will make up for it's summer losses in the winter to some extent as it's essentially a heat pump for the rest of the building.

[!!!]

Losing 5% of your light in a vented hood/cooltube sounds small. The guy at my hydro shop said a cooltube will cut about 1/3 the lumens.

You're right in that things add up. Being able to get the most out of your lights, equipment, nutes, genetics, etc is a skill. Priority usually forces the grower to focus on certain things and to cut back on others. i.e,. losing 10% yield in exchange for more security, or losing 40% yield in exchange for lower operation costs (no intention to sell) etc.

Check out the Yield-O-Rama for the numbers, so you can maximize your yield/space/etc: https://www.angelfire.com/cantina/fourtwenty/yor/yor.htm

[One Love 731]

I very much agree with a lot of this. but will not be giving up on my air cooled hoods any time soon.Why run an ac when its 40c outside? couldn't you just pump the hot air outside via a carbon filter and have a passive intake via a furnace filter box, this would also help create negative pressure, granted when using Co2 nothing beats a good AC when outside temps are high outside but when the temps drop you can achieve an awful lot by having over sized fans cooling your lights. Its my experience that if your pumping 40c air through them, more than likely your problem is not going to be keeping things cooled down its going to be keeping the temp high enough by using a fan control switch or a heater. I also think it would be a good idea to pump some hot air into the rest of the home if your not using Co2 and you can afford the carbon scrubber ect. The best thing I have heard in this thread is to always concentrate on the weakest link, rather it be nutes, genetics, lighting, temp's,RH, ect., ect. Thats how its done. Anyways just my Karma, One Love

[Rocky Mtn Squid]

the formula for offsetting watts with btu's is 1 watt per 5 btu. 1000w needs 5000 btu.

If this figure is correct, you would require a 1 Ton AC unit that would pump out 12,000 BTU's of cold. I own such a unit, and know that it consumes 1250 watts of juice to accomplish this. Hence, it's a total pig on power. Moreover, it's noisey, doesn't like being pushed too hard while operating-strains easily- and requires to be manually emptied of H20 on a daily basis.

Has anybody seen any water cooled system's....??? I know that Hydro Innovations has a very slick set up for water cooling both your lights and your nute rez using the same chiller. They claim it's 40% more energy effecient than an AC cooled system.

https://www.youtube.com/watch?v=M0uRrMvfucY

https://www.youtube.com/watch?v=Culol...eature=related

[superultramega]

You still need a water chiller for that system. you can gain some efficiency from a large reservoir, but anything over a couple 1kw-ers you'll need additional cooling.
They have those running at my local hydro shop hooked up to a chiller. They tell me the chiller doesn't run too often but it was a necessary addition. It's cooling 2kw.
A/C units, or anything else really, don't run at 100% efficiency. To get 5000 watts of cooling it may take 6000 watts of elec for example. Trying to match the input of your light to a cooling unit is not 1 for 1. Much of the energy used by the lights is converted to light energy rather than heat. The same is true in your a/c where a great deal of energy is converted to heat rather than extracting heat. While I like the cool boxes you can't escape the law of conservation of energy. Transferring heat into one additional substance carries it's own losses.

[superultramega]

BTW 1000watts is about 3400 btu

But I think he was saying you need 5000btu a/c to cool each 1000watt light. That seems about right as I run 2kw air cooled with a 6000btu a/c that runs about 80%

[Dankblueberries]

Originally Posted by superultramega

BTW 1000watts is about 3400 btu

But I think he was saying you need 5000btu a/c to cool each 1000watt light. That seems about right as I run 2kw air cooled with a 6000btu a/c that runs about 80%

There are a lot of factors to consider when you are sizing your ac for your grow. Outside temperature is a major factor to consider. The difference between summer and winter is huge. In the summer, my setup uses 3000 btu per 1000 watt, in the winter half of that. Humidity is a factor also. If it is dry, the ac runs less efficient. To give you an example of how I came up with 3000 btu per 1000 watt light, here is how mine is set up.

I find a large garage that I can build a smaller room inside the garage. Inside this room is where I grow. The Ac unit(s) blow cold air inside the grow room, while the back of the AC blows the hot air into the rest of the garage. This space that is in your garage, yet outside of your grow room, has a charcoal filter strapped to the ceiling, blowing the hot air either inside your living space (free heat in the winter) or outside the house/garage.(in the summer) If this garage area that the ac units are dumping their heat is small, or your exhaust filter is not getting rid of the heat fast enough, than the ac units will not work as efficiently.

I have seen a set up where someone custom built a box straight off the back of the AC, and inside this box, was a charcoal filter sucking the hot air to the outside. So no hot air from the AC ever escaped the custom box. He said the ac unit worked even better this way as it never tried to cool itself with the hot air it just blew out the back. I liked the idea.

The best of course is to have a split ac, where the condenser sits outside. If you want to run it in the winter you have to get a model that is made to run when it is freezing outside. I guess people would wonder why you have an AC running in the winter, but if you are running a legal(state law) grow, who cares. I have not used a split ac, but I will in the near future. It is the way to go if you are not worried about people wondering.

Hope this clarifies some questions.

[Dankblueberries]

Originally Posted by VerdantGreen

im interested in your record Dankblueberries

im organic soil so couldnt comment about the ppm (although i usually find less is more with nutes)

i would have to agree with the air cooled hoods - not only does the glass cut down light but i doubt if the reflectors are that efficient. the other thing with lights, is make sure you have them high enough to spread for a good footprint. if you are looking for optimum grams/watt then you want around 60watts/square foot.

V.

I have been consistently getting over 3 lb per 1000 watt light with a high yielding strain that finishes in 9 weeks, in a custom made ebb and flow table using chemical ferts. My record is 3.4, and I know I can beat it, because conditions were less than optimal at that time. My goal is to get 4 lb per 1000 watt. These numbers are stem snapping, dry, weight.

On the organic side, my record was my last run which was 2.7 lb per 1000 watt with an 8 week strain,(started from seed) and this was in 3 gal grow bags, filled with a peat moss mix that I came up with, fertilizing with sea bird shit and many other organic amendments. Each plant, was hand watered.

These numbers didn't happen over night. I have been refining my technique for decades. When people ask me what is the main reason I get these yields, I tell them, "get an air conditioner so you can make your room a closed system and fill it with CO2"

[VerdantGreen]

thats a good yield Db!. my setup is much smaller than yours with organic soil and no CO2, but if you are looking for some g/w competition as you mentioned earlier, then check out my diary - most of my strains aren't high yielders, but from my calculations my record (with a high yielder) just beats yours

V.