How many BTUs do I need for a room air conditioner?

Question

Southern California. One room, approx 175 SF. Poorly insulated, in that their is a patio door and 70s style aluminum windows. Looking to buy one of the portable units on sale currently at Costco. 10 pts for some good advice, thanks.

Answer 1

12,000 BTU's equates to 1 ton

1 ton equates to 500 to 700 sq. ft. of space to cool, depending on who you ask.

I agree with regard to the portables.

In your case, I also agree with not less than 8,000, but given the situation, that may not offer much.

Just my two "sense"

Answer 2

About 8000-10,000 BTU's should get you out of trouble, but this is a mighty big portable unit, and being a commercial a.c. mechanic, i dont even know if they exist. Portables are more trouble than they are worth. You have to have a window open to discharge condenser air and empty the condensate drain every hour. If it is your house i would put a permanent split system in. Hope this helps

Answer 3

I have a portable unit.  I bought it as a temporary stop gap until I install the whole house unit.

It has it's draw backs, but they are solvable.   You have to have it vented to the outside.  You could use the patio door and put a panel in the rest of the space.  You need about a six inch opening for the vent tube.  To lengthen the vent tube I have used flexible 6" insulated ducting.  The other issue is that you still have to empty the drain pan.  Not once an hour but about twice a day depending upon the humidity levels.  To get around this i built a small platform for the portable to sit upon with a 5 gallon bucket below the unit.  Now I only have to empty it once every few days if i want (but do it daily).  

They are only so so efficient.  But if it is your only choice I would go with it as a temporary not a permanent solution.

As to size, the larger the better.  BUT make sure you have the electrical hook up required.  If you go over 10,000 it may not work on a single outlet etc.  Your budget will make the final decision.

Answer 4

I would buy nothing less than a 8,000 btu. Here is a good reference. http://www.csgnetwork.com/acroomsizecalc...