Heat from hps

Baz

Well-Known Member
I have an 8 x 8 atic grow room completly sealed off with foam boarding and am planing on buying 2 x 600 hps, will i have a prob keeping the temps down? also will it eat alot of electric?

Would mh be better?
 

desertrat

Well-Known Member
1. I have an 8 x 8 atic grow room completly sealed off with foam boarding and am planing on buying 2 x 600 hps, will i have a prob keeping the temps down?

2. also will it eat alot of electric?

3. Would mh be better?

4. why am i asking questions when i'm now a veteran on riu?
1. yes
2. not really. 1200 watts is what a space heater would use.
3. depends on your set up. if you have separate veg and flower areas, get one mh and one hps. if you're using one grow area you can either use 2 hps or one of each.
4. hi baz. i have no idea why you are asking questions. :lol:
 

Baz

Well-Known Member
Ha ha i built the room and have money for bulbs, but because its in the atic and lined with foam boards, i dont want to buy new bulbs n hoods ect and have some serious heat issues

Im a veteran cfl grower only ha ha, and i had heat issues at the end of my last grow, was thinking of using cool tubes and venting all the heat into a chimney right at the side of the room do hps and mh put out around the ame heat and someone told me the ballests buzz, that true?
 

desertrat

Well-Known Member
yes, mh and hps of the same wattage put out about the same heat.

the electronic ballasts don't buzz.
 

Baz

Well-Known Member
Ok thanks, im making the room completly airtight, ive already fitted all the 50mil foam boards very tightly and im going to duct tape all the joints and corners so its extra air tight its also got a chiney in the coner that i can tap into

Im thinking about putting some ducting close to the two bulbs and venting them both into the chimney might be able to get away with no fan, as the chimney should pull the air out on its own, i think n e way, then maybe a intake fan pulling through the roof tiles

What you think?

Also do you think the silver boards will act like maylar?
 

chazel

Well-Known Member
let me know how the temps go man!
iv got a 400 hps, that im plannin 2 stick in a 2x4x6.5 - ish space.
ballast brands may differ , but mines does hav a low dim hum, id say the bulbs themselfs make more noise tho
 

desertrat

Well-Known Member
you're going to need a fan to pull or push air through the lights - they need quite a bit of airflow to cool them properly. for two lights you want something like a 440 cfm inline fan.

the boards depend on what the reflective material is made out of - if it's just paint then you're ok. if it is something like a foil coating i would avoid it because of possible hot spots.
 

chazel

Well-Known Member
well i hung it up and tried it out , left it on for a wee while to guage a rough temp as iv still to put everything else in there - glad to say the light should do !
iv been lookin into a cool tube for a while coz im sure the hour i left the light on for doesnt quite get it to its peek heat , but the reflector i hav now seems to be pretty spot on for directin over the space i have. . more worried about keepin the bulb surface clean to aviod explosions . . maybe i should take a page from the bazmiester and go cfl?
 

Baz

Well-Known Member
well i hung it up and tried it out , left it on for a wee while to guage a rough temp as iv still to put everything else in there - glad to say the light should do !
iv been lookin into a cool tube for a while coz im sure the hour i left the light on for doesnt quite get it to its peek heat , but the reflector i hav now seems to be pretty spot on for directin over the space i have. . more worried about keepin the bulb surface clean to aviod explosions . . maybe i should take a page from the bazmiester and go cfl?
Lol im going from cfl to hps and you going to cfl ha

How many plants can you grow under a 600 watt hps light?
 

Baz

Well-Known Member
you're going to need a fan to pull or push air through the lights - they need quite a bit of airflow to cool them properly. for two lights you want something like a 440 cfm inline fan.

the boards depend on what the reflective material is made out of - if it's just paint then you're ok. if it is something like a foil coating i would avoid it because of possible hot spots.
Yea its foil coated kingspan
 

shnkrmn

Well-Known Member
Lol im going from cfl to hps and you going to cfl ha

How many plants can you grow under a 600 watt hps light?
I've grown 9 plants in 2 gallon containers under 1 600W. They were two foot plants. I'm growing three plants now under 2 600W. They are much bigger.

Doesn't your attic get hot in the warm months apart from the light burning? Do you really need to have the foamboard enclosure? It's your attic, after all. You mentioned having heat issues in your last grow, which was CFL? Was that just the ambient temperature in the attic or something else?
 

Baz

Well-Known Member
I was using cfl's under my stairs and it got hot because i had 20 of them and no real extraction, prob will be hot in the summer as i'll be pulling warm air in to a warm room hmmmmmm

This may sound crazy but i have a small fridge with a tiny freezer compartment in the top, im thinking of cutting a hole in either side of the freezer bit and letting my ventilation system run through it before hitting my bulb, what ya think?

Hmmm how to get the freezer through the hatch...
 

chazel

Well-Known Member
go on san! i turned 1 of those shit wee porta/car fridge cooler box things into a make shift propagator as it had a heat function aswell , works a fookin charm aslong as i keep the lid open( pressure cooks otherwise) coupe wee fans in it help circulate anaw.
as far as the hatch goes . . i duno , im the guy who measures once iv struggled to fit it through for an hour. .
 

Baz

Well-Known Member
Lol yea me too, would work in the summer tho, would be just like aircon

The reason i have insulated it to the max is i dont want no heat escaping at all, just what i vent into the chimmney, as im sure that would look completly normal to the eye in the sky :)
 

shnkrmn

Well-Known Member
Lol yea me too, would work in the summer tho, would be just like aircon

The reason i have insulated it to the max is i dont want no heat escaping at all, just what i vent into the chimmney, as im sure that would look completly normal to the eye in the sky :)
I don't think about stuff like that much, but wouldn't placing the light right next to the chimney make its heat signature blend in with that of the chimney? I mean, heat sensing equipment isn't really like a camera, it doesn't provide a resolved image, it would just look like the warmth of the chimney. Now if you had 10 1000 watters up there . . . . . but of course, then the flames would be visible to the naked eye. LOL
 

Baz

Well-Known Member
I don't think about stuff like that much, but wouldn't placing the light right next to the chimney make its heat signature blend in with that of the chimney? I mean, heat sensing equipment isn't really like a camera, it doesn't provide a resolved image, it would just look like the warmth of the chimney. Now if you had 10 1000 watters up there . . . . . but of course, then the flames would be visible to the naked eye. LOL
Yea thats the idea, but im sending it through the chimmney so it comes out of the top, also the smell will go out that way too, just i thought with the heat seeking tech they got, if i didn't completly seal and insulate the area in my atic my roof would propably stand out like a sore thumb

Houses are designed where the floor of the atic is the final (top) layer of insulation to stop the rising heat escaping out of the house, then the roof itself has breathable felt then tiles, to help the roof space breath. So any escaping heat would stand out.
 

Antman

Well-Known Member
This may sound crazy but i have a small fridge with a tiny freezer compartment in the top, im thinking of cutting a hole in either side of the freezer bit and letting my ventilation system run through it before hitting my bulb, what ya think?

Hmmm how to get the freezer through the hatch...
I'm pretty sure that won't work. Once the inline fan kicks on it will suck the cold air outta that freezer in about 5 seconds. The freezer will never make enough cold air to be able to keep up with the fan. One other thing to consider, you said you're completely sealing the box. Your plant will need fresh air, no? Do have a way to get air into the box?
 

Baz

Well-Known Member
I'm pretty sure that won't work. Once the inline fan kicks on it will suck the cold air outta that freezer in about 5 seconds. The freezer will never make enough cold air to be able to keep up with the fan. One other thing to consider, you said you're completely sealing the box. Your plant will need fresh air, no? Do have a way to get air into the box?
Yes im pulling fresh air in via some ducting and a fan, the type of freezer box im talking about is about as big as a shoe box and has a build up of ice, also if i never defost it it will eventually be almost full of ice with a small void for the air to go through, im sure the ice should be enough to cool the air as it passes through, thats how air con works right?
 

shnkrmn

Well-Known Member
Something to consider though, is that the freezer has to radiate heat equal to the cooling that takes place, right? Through external coils usually. It would be hard to capture that heat and get it out of the attic efficiently, so it might cause the kind of heat you're trying to avoid! Plus the added elec.

And in an air conditioner the coils contain freon which gets much colder than ice and they have vastly more surface area to cool the air passing through, so much, much more efficient than a frosted up icebox (which are less efficient when they ARE full of frost and the compressor labors and overheats, etc, etc.

Yes im pulling fresh air in via some ducting and a fan, the type of freezer box im talking about is about as big as a shoe box and has a build up of ice, also if i never defost it it will eventually be almost full of ice with a small void for the air to go through, im sure the ice should be enough to cool the air as it passes through, thats how air con works right?
 
Top