# Thread: Do you think this formula Good ?

1. Regular Guest
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Aug 2005
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I have this Room in my Farm

Long 9m X Width 6m X High 3 = 162

One s meter =300 X 162 = 48600 BTU

48600 BTU / 12000 BTU = 4.05 Ton

This formula for A/C cooling

Do you think this formula its give good condition ?

thanks for

2. Please click on this tab at the top of the page to size the for the heat gain of your house, the only true way to do it.

3. Originally posted by welhan
I have this Room in my Farm

Long 9m X Width 6m X High 3 = 162

One s meter =300 X 162 = 48600 BTU

48600 BTU / 12000 BTU = 4.05 Ton

This formula for A/C cooling

Do you think this formula its give good condition ?

thanks for
This is Turtle.

Hummmmmmm, i have a camp on the lake near here and it is about the same size as your stating about your building and it has a 22,000 btu window unit in it and it does fine at out door temperature of well over 100 degree f.

Your calulator says i should use 48,000 [4 ton] and i'm doing fine on 22,000 btus [ 1.83 tons] , hummmmmmm, there seem to be a error here somewhere.

Welhan , i have been down this road 40 years and have never found any straight out formula that would do as a cooling load calculator and work good as to keeping the right temp. in the house.

You really need to get you a HVAC Manual J calculator and run it on your house. this is the only true guage as to getting the BTU's you need.

If you wanted to talk about it e-mail me. turtle4airea2bellsouth.net , you know change the 2 to what it should be.

TURTLE

[Edited by Mod2 on 01-22-2006 at 10:26 AM]

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THANKS FOR HELP ME MR.turtle

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## Formula

Welhan, you might have a good "ballpark" sizing number if you took the 3m height out of your calculation. The "300" number is purely subjective, as some contractors "learn" what they can use for a given "local" design condition. don't oversize the unit. As stated, a Manual J calc is always best.

Jed

6. You really don't want to put 4 tons of air into a 550 sq ft room unless it is a screen room with open roof. Do the homeowners calculation at the top of this site, it will pay for itself not needing 4 tons of air.

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Look at this guys past posts before giving any sizing advice. He lives in Saudi Arabia and has a summertime high temp of 140F. I don't think any of our good intention guesses will be close. He definitly needs to do a Man J.

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Good point!

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## What's next ?

Originally posted by welhan
I have this Room in my Farm

Long 9m X Width 6m X High 3 = 162
One s meter =300 X 162 = 48600 BTU

48600 BTU / 12000 BTU = 4.05 Ton

Do you think this formula its give good condition ?
No but it's in the ball park.
You need somewhere between 0.5 - 10 tons
Depending on whether you keep the windows open or not.

L O L

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## thankssssssssssssssssss

Its my mistake to Wright here I thought get help but my behavior STOP me to say bad things any way thanks for good to people always helping this is last time to visit this web page.

welhan

11. Professional Member*
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Don't get offended because of what I said because it wasn't meant that way. I only wanted to point out to everyone that you live in a different enviroment than we, in USA, do. Other than the guys that live in the desert southwest, most of us don't have experience, on a day to day basis, with the extream heat that you have. I'm in Michigan and a room that size, 486 sq ft, would not even need a ton of cooling. My initial response to your post would be that 4 ton is way too much and I think the rest of us would respond the same.
So you see that it's not that we don't want to advise, but we really can't based on our experience without doing a heat gain on the structure.
Wally

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