Sizing A/C


Old 06-20-18, 12:06 PM
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Sizing A/C

I need to replace a through-the-wall a/c in a very small room -- 10'x12'. I should have 2,400 - 4,000 BTU, depending on whose rules I believe. The problem is that the smallest through-the-wall unit I can find is 8,000 BTU. There are a few 5,000 BTU window units, but I understand they can't be installed in the wall.

8,000 would be 2 or 3 times larger than it should be. How do I get around the fact that a/c's shouldn't be oversized?

Old 06-21-18, 05:57 AM
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For me personally I would figure how to put the 5k unit in the opening. Care needs to be taken to not block the side (intake) vents on the unit.

If you Google install window ac unit in wall you will find lot's of info on doing it as it is not uncommon.

Downside is if you have trouble with ac unit there is no nice sleeve to pull it out of and have to remove entire unit. Just like if it was in a window.
Old 06-21-18, 07:15 AM
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I have a small bedroom that size in my house and it definitely needs a 5000 BTU. I can't imagine anything smaller cooling the room. Do they even come that small? Have never seen one.
Old 06-22-18, 08:42 AM
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Sq ft is a poor way to size. Following the charts- you end up with up to twice as much capacity as required.

Window units btw are crippled by having the supply air get circulated back into the intake and poor throw, causing reduced capacity and short cycling.

The amount of cooling you can get from these units can be greatly increased by keeping the fan speed on high, directing the air in the right direction and using fans to distribute it.

Do what you can do to make a 5000 btu work.

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