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Air con unit help

Hi guys,


I know there is an air conditioning thread a few posts below but I’ve read it and didn’t get the info I’m after so thought I’d start a new one!


Basically, this heat at the min is stressing me out! The bedroom which I have my tent in is south facing, I have no choice of setting up elsewhere either unfortunately. It’s getting too hot in the tent and I can’t see how turning the fan up (if I could, noise restrictions) will bring the temps down if the air outside I’m pulling in is 30 degrees already! 


Looking for recommendations on a air con unit for an average size bedroom please.. Can get the tape out if needs be!


I understand it’s going to be expensive but if it means I can have a perfect enviro to grow perfect herb in every summer then it’s a worthwhile investment surely?



Aphat :spliff:

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Just run your lights at night, and leave the window open a bit to cool your grow....aircon isn't worth it, trust me.

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OK, you may find that there is a minimum temperature you can get to within the operational envelope created by your fixed placing, your noise requirements, your available space, and your budget. I know you already know it will be expensive but the costs rise dramatically when you get to quiet AND effective AND not massive air con units.


Where we should start is numbers, how many KW of lighting do you have?


What type? (HPS,LED etc)


How much air is being put through your tent per hour/minute?


this will tell us the power/hr we need to deal with, which in turn will suggest a size of aircon. Knowing your budget will then tell us whether the aircon you need is within your budget or whether you will have to find alternative cooling methods. I have heard some people get good results from using a product called 'chill' which help a plant combat heat stress.


That said, I also had a heat issue recently (surprise, surprise) and having already purchased a 1.5KW portable aircon, I put it in my room and the room got warmer than without even with the exhaust of the aircon pushed against my carbon can. The aircon wanted to shift a lot more air than I was sending through my exhaust. It was MUCH noisier too.


As the only real choice was sending unfiltered air straight to the outside world it was a non-runner.


So I re-evaluated my ventilation, removed some kinks from the ducting and shortened some lengths and my room temps dropped 3 degrees. In the hot weather (30c+) they got to about 32-33c. Hotter than I would want but not so hot I would panic. Those 3 degrees are significant at those temps.


You also do not mention the type of system you are running, if hydro I would say a nutrient chiller would be more important. Plants can cope with warm tops much better than warm roots.


I will stop waffling now ;)

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We have a portable Air con unit and it makes the room nice and cold but its loud! :shock: when its on you can't hear each other talking:wallbash: 

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Posted (edited)

I purchased a Honeywell HDE020E1 20 litre Dehumidifier a couple of years ago for £220 from argos, I see its now £120 !


It has a cold setting and it works real well and its pretty quiet.  edit : It is not a cold setting, it is a light that tells you it is very cold outside haha.  I have pulled it out the shed and set it running, it is very quiet and provides a nice breeze which feels very cooling, but it is not a air cooler, sorry. All I can suggest is getting bottles of water in the freezer then dangle the in front of a fan and let it melt over several hours, rinse and repeat.   AC items are loud so good luck in your search ! 


Pulling mine out tonight so I can have a good nights sleep ;)

Edited by Inspiration101

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Posted (edited)

If you do choose the air con route I found this from a quick search  two sources guess add both measurements will give you a Rough idea of what cooling requirements you need as per area and lighting


As a general rule we advise you to buy an Air Conditioner with a minimum 7,000BTUs as this is the minimum required to cool a small room (18sq/m) on a hot day. Medium rooms (24sq/m) need around 10,000BTUs and larger rooms and office spaces (36sq/m) require around 15,000BTUs.

BTU (British Thermal Units) refer to the cooling capabilities of an air-con unit per hour. So, for every 600w grow light around 2400 BTU’s are required. For every 1000w grow light around 4000 BTU’s are required. After calculating the total BTU’s needed for your lights, add 20%.  


Edited by Jim Herbert
Tidy up

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