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Heating & Cooling

Help with calculating BTUs for my high ceiling loft

Could someone help me figure out how many BTUs  I will need in an air conditioner for my loft?

Our floor space is technically 875 sq/ft, divided onto two floors, with 18 ft ceilings.  It is all open air, so it's like one big room.
I measured the length and width of the bottom floor and it's 32' x 19'.

We face east, with floor to ceiling windows (with pull-down shades).  At the back are two "regular" windows that face west, also with shades. Our floors are concrete and the ceilings are wood beam. The building is fairly new, (2008) and is LEED Silver certified, so we don't have any issues with drafty windows/doors, etc. Neither of us cook all that much, so stove/oven heat is not an issue.

We are considering either a Mini-split, or two portable units (one for each floor)

So, what are we looking at for BTUs? The 18ft ceilings and all the open space have me stumped.

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Posted 2015-06-26T17:35:52+0000  by REMgirl REMgirl

Hi REMgirl,

Thanks for your question and welcome to the community!

When it comes to determining BTU's for your air conditioning unit, square footage is the final size needed. 

At least with in-wall A/C units, you would need at least an 18,000 BTU size.

Window BTU calculator

However, considering that would just barely cool down the space, however with adequate placement of ceiling fans can drastically help pull the cold air throughout your loft.

Try to avoid an unnecessary larger 24,000 BTU model if it isn't needed, as 'too much cold' can lead to humidity in the air and would be a waste of money. Only use this model if the heat has significant issues in the upper portion of the loft, or you have no ceiling fans to circulate the air.

Lastly, you will need to install a dedicated circuit (breakers, wire, outlet) to successfully power up the A/C unit. This is due to the larger amount of power (20 amps typically/ 220 volts) needed for it. You may need a local electrician to go over this with you in terms of installation.

Let us know if you have any additional questions, and I hope this has assisted you.


Posted 2015-06-27T15:55:35+0000  by Joseph_HD_ATL
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