# Questions about heat, space, & cooling



## mpmiller (Jul 17, 2008)

How hot does a 1000w hps light produce? 600w hps? 

can a 6" inline fan w/ 424 cfm flowing thru an EasyCool 6 Reflector keep the temperature cool enough w/ 1000w system? how about with the 600w system?

if putting the 1000w hps into a plastic box 4.5Lx3Dx6H be over kill with lumens? heat?


Thanks!


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## King Bud (Jul 17, 2008)

I have not seen anywhere the heat output (BTU) for lights. If anyone has, _please _share 

For cooling, it's a good idea to know your intake temperature.
Pretend you intake air from outdoors, where it's 30c. No matter how many cfm, you will never cool your room to bellow 30c. 

I don't think a 1000w hps should be put in a plastic box, regardless of how cool you can get it. It just sounds like an accident waiting to happen.

edit: This link has something usefull guidelines for estimating needed BTU


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## mpmiller (Jul 19, 2008)

I was thinking of using the 6" inline fan with ambient temp of 68F. Guess that won't be enough to cool off 1000w bulb, will it be sufficient for a 600w?

I looked up converting watts to btus and came up with 1000w/h=3414btu/h, so I would need 3414btu/h of cooling and 2048btu/h for 600w light. 

How much cooling can I expect from a 6" fan blowing 420cfm at 68F?


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## POTUS (Jul 19, 2008)

mpmiller said:
			
		

> I was thinking of using the 6" inline fan with ambient temp of 68F. Guess that won't be enough to cool off 1000w bulb, will it be sufficient for a 600w?
> 
> I looked up converting watts to btus and came up with 1000w/h=3414btu/h, so I would need 3414btu/h of cooling and 2048btu/h for 600w light.
> 
> How much cooling can I expect from a 6" fan blowing 420cfm at 68F?


 
With only 13.5 sq. ft. of growing area, a 1,000 watt light is over-kill, especially with only 6 feet of vertical space.

The light has to be at least one foot from the top for safety. Then adequate space between the light and the plants to prevent burning from both direct heat and the IR heat.

My grow space is 3.5' x 5.5', with an 8' ceiling, so it's pretty close to your grow area size.

I use two 430 watt HPS with bat-wing reflectors. The room is a walk-in closet with the door taken off and faces into a 12' x 12' air conditioned room. I use only a pedestal fan to move the air from the closet into the larger room and it's pulled into the home air conditioning system via the return air vents. I've never had a problem with this setup. The lights run only at night and in the winter, the room supplies almost all of my heat in the house.

I live alone and NOBODY comes into my home, EVER, FOR ANY REASON. My property is fenced and the house is in the middle of a large piece of property, so I don't have to worry about smell reaching the neighbors.

If you have to use a ventilation system, you have only 81 cubic feet of space. A fan that pulls 424 cubic feet of air per/minute will be as much as you could possibly need as long as your air intake is from a cooler source that will supply a minimum of 424 cubic feet of cooled air per/minute.

You might want to think about using two 400 watt lights. The light is spread more evenly over the canopy and provides much better growing than a single light will.

BTU's of heat output isn't what you need to be worried about. The replacement of the air within the room to fresh air that is loaded with natural CO2 and is as cool as needed, is what you need to think about.

So, yes, your fan is large enough for two 400 watt lights or even the 1,000 watter. You limit your vertical grow space severely by using the larger light however. 

I keep my 430 watt HPS at exactly 18" from the canopy and a foot from the ceiling at the closest. Having Firemen putting out a fire in your grow room is a really, really bad idea. :shocked: :bolt:


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