exhaust heat

Originally Posted by kailiwela44

how much heat does a 250hps give? If i were to vent the exhausted air into the ambient air, will it create a temp influx causing temp increase within my grow cab? If so, what about a $150HPS?

Originally Posted by kailiwela44

how much heat does a 250hps give? If i were to vent the exhausted air into the ambient air, will it create a temp influx causing temp increase within my grow cab? If so, what about a $150HPS?

Originally Posted by kailiwela44

sorry for the confusion. I am doing a cab grow. i hope to use a 250 HPS inside the cab, but i need to exhaust both air from the cab and the heat from the light into the room i have the cab in...So, if i were to exhaust the heat into the room how much would the ambient temperature rise?

Originally Posted by kailiwela44

sorry for the confusion. I am doing a cab grow. i hope to use a 250 HPS inside the cab, but i need to exhaust both air from the cab and the heat from the light into the room i have the cab in...So, if i were to exhaust the heat into the room how much would the ambient temperature rise?

Originally Posted by Fman

I understand what you want. I hope this pic. helps. The intake air that is coming in from under the house is 76*. There is a 200 mh cfm 25' away pushing air to my room. The exhaust fan is a 350cfm drawing the hot air out the roof of my room. Where are you going to get your fresh air from? If you are going to get your intake from the same place your exhausting into, you might find that to be a problem. As you can see my 250mh is 90* and thats with cooler air blowing over it . I hope this helps. Also I included pics of my air ducts . Both the room and light are cooled from the same plenum, thats behind the wall on the floor. I know a mh is not a hps, but I dont think there is much difference in heat. Watts is watts. And that is where the heat come from (I think).

watts is the capacity to do work...in a light bulb the watts do two things...give off light and heat....in efficient bulbs the ratio of light to heat is high...in less efficient bulbs the ratio of light to heat is low...so watt is watts but large hid watts are less heat per watt and more light per watt than most other commercially available lighting

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Originally Posted by Fman

I understand what you want. I hope this pic. helps. The intake air that is coming in from under the house is 76*. There is a 200 mh cfm 25' away pushing air to my room. The exhaust fan is a 350cfm drawing the hot air out the roof of my room. Where are you going to get your fresh air from? If you are going to get your intake from the same place your exhausting into, you might find that to be a problem. As you can see my 250mh is 90* and thats with cooler air blowing over it . I hope this helps. Also I included pics of my air ducts . Both the room and light are cooled from the same plenum, thats behind the wall on the floor. I know a mh is not a hps, but I dont think there is much difference in heat. Watts is watts. And that is where the heat come from (I think).

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Originally Posted by scott06

I get it now, you want to know how much the heat in your room, not your cab, would rise....correct?

In a sealed environment your room and cab would eventually reach the same temp...one of those thermodynamic priciples....but rooms are far from perfectly sealed and the lights are cycling on and off so I can't predict the rise with any accuracy...but I never head of exhaust heat from a 250w cab ever causing a problem...the heat should disapate quickly if the cab is venting into a room bigger than a closet...is that what you are trying to find out?