Struggling with heat/low humidity air flow issue

I am growing in a hot attic it measures around 4mx2.5mx2.5m (lxwxh)

I am running 6x630w cmh lights

Passive intakes

8inch isomax fan

Temps getting up to 36 degrees

Humidity is like 10 degrees


I am wondering do I buy a 10 inch high power isomax 2430cmh will this solve my problem? (I would also put in two misters on a controller)

Any help is very appreciated

Thanks

I used to have an 8" Isomax , good fan but I wouldn't buy one again, not really quiet for the money.
Get a hurricane or gecko box fan, 12" and get an intake.

You really need to shift a lot of air to run that much in a hot attic.

I know folks run two 600hps in attics in uk and need massive airflow to do the job.

Where you venting the heat to?

The heat is just venting through the tiles in a cavity I made, it's probably 4 cubic metres

FentonsBalls said:

The heat is just venting through the tiles in a cavity I made, it's probably 4 cubic metres

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Do you mean you cut through plaster board and the heat goes into the space between tiles and ceiling

Effectively yes, it is very well sealed though

FentonsBalls said:

Effectively yes, it is very well sealed though

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Still a massive impedance on the fan though, going to be restricting the airflow and making the fan work hard.

Personally I like to tap into a disused chimney. If not that then a series of roof vents.

Problem is you really need about 4000m3ph fan assuming a summers day is 25 degrees c and that would probably blow your roof off.

Not sure how effective swamp coolers are but if your at 10% humidity then would help to some degree with both.

@Renfro whats your thoughts on a hot attic with low rh and way too high temp?

coreywebster said:

@Renfro whats your thoughts on a hot attic with low rh and way too high temp?

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Don't do it. lol

Really, it's too damn hot, that maths out to 96.8F. Ouch. I mean you might deal with hitting 90F but 96 is just not gonna work.

An attic is truly the worst place to grow. Winter comes and you have the opposite problem.

FentonsBalls said:

Effectively yes, it is very well sealed though

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Are you European?

UK pal

If you put one of these massive swamp coolers in one end of the attic and have a open gable vent on the other you might get your temps and humidity numbers to a workable area. But if the humidity spikes outdoors (rain) then your swamp cooler won't cool as well but humidity will get way to high for flower.



Really though you are fighting such extremes that you will run into problems and end up hauling all the gear back down from the attic lol.

UK? Don't you have higher ambient RH%? Swamp coolers really only help if the ambient air is dry. They cool the air by adding cool water content.

Hmmm I believe airflow may solve the issue alone, I mean ambient intake temps outside the room don't go above 24degrees it's just getting someone with a better know how of airflow to help balance these.

Most recent grow pulled off just over a gpw with 600hps in euro reflectors

FentonsBalls said:

UK pal

Click to expand...

Yeah I thought so from the Isomax fan.

If you have the luxury of owning the house and have disused chimney that's not falling to bits then that would be my first choice.

Don't know if its possible to air cool 630 cmh, but if its workable then that going to help.

After that an evaporative cooler can help with both humidity and some of the heat.

Cant understand why its 10% rh though. In UK.


Ive set up a lot of attic grows, but on the slightly smaller scale and always had the option of many roof vents or chimneys.

Yes we do that's why I believe the airflow is too low, the air is staying in the room too long and drying out

Unfortunately it's a not got a chimney and the agreement I have is no holes/modifications to structure

Im half tempted to stick a huge tornado fan up there and see what happens maybe use the can to blow air in?

End of the day airflow would be enough with ambient of 24c , but its such a lot of airflow and such a restrictive method of extraction you currently have.

It will take 4200m3ph extraction to stay 5 degrees f above ambient with that wattage.

Maybe find a happy medium taking out a couple of lights in summer and still increasing extraction.

The swamp cooler is a massive blower and can be run with the pump on or off. So it could really bring in a LOT of fresh air and if you want it will also humidify the air. You will want an "open window" to maximize flow (passive exhaust 2.5x the intake area).