Winter air vented directly through cool tube hood

jijiandfarmgang said:

LOL, has anyone even ever tried this in this thread?

As described above it will literally rain from your intake from condensation. If you do a search you should find others talking about it.

This isn't breaking science.

- Jiji

Click to expand...

Haha, yeah i've done it a few times
Straight makes it rain, for sure. Especially if the growroom is over 40% humidity.
IMO, if it's that time of the year, and the air used to air-cool is too cold, don't air cool. Take that glass out, and enjoy(not sure about cool tubes). Unless of course you are using your rooms filtered exhaust to air-cool, which is what I think the OP should do

Even though air-cooling with cold air is not ideal:
I've never had a bulb crack, blow up, whatever, when air-cooling with cold air. Of course, you wouldn't want to heat up the lamp, and then blast with freezing air. THAT prob wouldn't be good. Constant air-cooling, is how most people do it though rite?

Someone here claimed Hortilux says they don't recommend cooling with cold air. I could not find such claim. But found this instead:

"Air cooling a fixture is designed to keep the growing area comfortable for the plants. Air temperature and flow rates need to be adjusted to help maintain this temperature. If the air temperature is really low than your airflow rates should be reduced.

Most of our products are not adversely affected by cold air, however, it may take the lamps a little while longer to come up to full brightness."

- See more at: http://eyehortilux.com/ask-a-question/faqs.aspx#sthash.PvXucaCh.dpuf

I've heard Gavita/DE bulbs absolutely need to operate hot though.

Hortilux is talking ^^^ about a cold start/ignition, anyways it's all mute as this tech(hid) has been around for decades now. We know how the bulbs are affected in certain environments.

If you run room temp air over your bulb in a cool tube will you see a 15-20% loss initially ???? NO, he (gavita) is still trying to sell you his product obviously Lumen loss/spectral shift will be negligible and a non-factor.

If your running sub-zero/cold outdoor winter air into your cool tube(as the OP is suggesting) will the arc cool down enough for it to experience a voltage drop???? I believe so BUT not 25%, that has more to do with the glass tube/dirt accumulation.

What's important in the end is EFFICIENCY no matter the scale of the grow when dealing with electrical costs.

Judging by the information gathered so far, the only obstacle is the condensation that a few have claimed will be an issue (I haven't done it so I won't say either way as to what's true). Which you can get a moisture filter to solve that relatively cheap.

Thanks for all of the information and discussion guys and ladies! Maybe one day when I can afford to run multiple rooms I'll attempt to apply this information.

Follow up question:

Is it ok to pull hot air for a cool tube, as in an attic grow? I've been pulling from my room but it's killing me with having to run the ac with a 6inch just constantly draining the room. Plus I could move my filter and create a passive void between veg and flower room. Attic temps hit 100 on a good day, stick around high 80s to 90s typically.

I know it will decrease the life of the bulb and also the effectiveness of the hood but I'm seeing it as the lesser of two evils. Kinda want to keep my ac and co2 in the room yah know....

So how hot can these 600 HPS get!? I would think them in stagnant air would be worse than even running 100 degree air over them..no?

Indagrow said:

Follow up question:

Is it ok to pull hot air for a cool tube, as in an attic grow? I've been pulling from my room but it's killing me with having to run the ac with a 6inch just constantly draining the room. Plus I could move my filter and create a passive void between veg and flower room. Attic temps hit 100 on a good day, stick around high 80s to 90s typically.

I know it will decrease the life of the bulb and also the effectiveness of the hood but I'm seeing it as the lesser of two evils. Kinda want to keep my ac and co2 in the room yah know....

So how hot can these 600 HPS get!? I would think them in stagnant air would be worse than even running 100 degree air over them..no?

Click to expand...

Almost a year old, nice.

If you move air, you're going to cool it down. At 530cfm, the air from my 600 watt is in the mid 70's upon exiting my ducting.
The operating temperature of most hid bulbs is well beyond the temperatures we run ours at. Imagine how hot an enclosed hps street lamp on the Vegas strip during one of their 100+ degree nights must get.
With those two points in mind I think it's safe to say you could pull it off successfully. That being said it also depends on your situation. Are you in a tent or in a room? If you're in a room is it not possible to vent from and out a window?
Another thought is to just run open hood and cool your room without a cooltube. Burt that assumes your room is big enough and that you're even in a room.

In a room.. But in an attic with no possible window to vent from..was going to pull from the eves but light and sound is a concern. Thanks for the input I'm going to set up up right now.

I'll bump this in a year to let you know my findings

HIDs run in parking lots all winter...

That said, it's not safe inside your house. Why take chances?

Anyone have any definitive info on this topic? Lots of semi conflicting info here.


I am cooling hood with outside cold air then venting it back outside.