Hood Venting Question.

I have a sealed room with 2 1000 watt HPS lights with 8 inch vented hoods. I have one exhaust line with one inline fan that pulls air from the outside of the room and pushes air outside the room, so the vent line is sealed. I currently have my in-line fan on a temperature controlled device so that the in-line fan is activated at about 78 degrees. I'm seeing that it is being effective. Temps stay between about 76 and 79. So the fan goes on and off. I'm curious if this sounds like a good design. I was thinking that I could have my in-line fan run constantly while the lights are on at a low speed with a speed controller. Then the fan wouldn't be turning off and on all night. But it would probably be on longer taking more elictricity. Thoughts?

it depends on the temp i have to cycle my fresh air fans right now as the temps get too low. for the summer with the ac i run a sealed system durning the winter i pull from inside the structure and vent out doors. we are hitting the 40's so i run my fans 15 minutes every 45 during lights off. i dont like to get below 55 do i use a thermostat that has high low. i adjust my fan according to the desired temps and the weather forcast i am a firm believer in lots of fresh air. i have a soil grow so i dont have resivors to worry about

are you reading the temps inside the light fixtures or the room? if the fans come on when the room hits 78, the light fixtures will be getting alot hotter so a speed controller might be better but if you are reading the temps inside the light fixture,bumping the temp a few degrees higher than the room temps would stop the fan from coming on when the lights are out.

mrmadcow said:

are you reading the temps inside the light fixtures or the room? if the fans come on when the room hits 78, the light fixtures will be getting alot hotter so a speed controller might be better but if you are reading the temps inside the light fixture,bumping the temp a few degrees higher than the room temps would stop the fan from coming on when the lights are out.

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I've got my temp thermostadt hanging about 8 inches from one of my hoods, you can see the black device in my avatar picture to the left. So the temps are being read there. I agree with you. If that thermostadt reads 78, the temps of my hoods and right next to my hoods are probaby 85. I may try to change it up a bit tonight and have my inline fan on when the lights are on, just at a lower speed. I'll see what happns to the room temps and also monitor the temps right next to the hoods. I also have plans to add a third hood and light so this would probably be even more important then, with more lights. Thanks!

abudsmoker said:

it depends on the temp i have to cycle my fresh air fans right now as the temps get too low. for the summer with the ac i run a sealed system durning the winter i pull from inside the structure and vent out doors. we are hitting the 40's so i run my fans 15 minutes every 45 during lights off. i dont like to get below 55 do i use a thermostat that has high low. i adjust my fan according to the desired temps and the weather forcast i am a firm believer in lots of fresh air. i have a soil grow so i dont have resivors to worry about

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You make a good point. I am in the mountains so this winter I'll have to make sure that I manage my low temps. Although, with 3 1000 watt hps lights and a low fan speed, we'll see what happens. I guess it is all about monitoring things closely. THanks.