Re: Sizing a Window A/C unit
When purchasing a room air conditioner, sometimes called a "window unit", the rule of thumb on finding one large enough to cool properly durng normal conditions is to first calculate the square footage of the area to be cooled. Once that has been done, it will give the approximate capacity for the area to be cooled. For example, a 10' X 20' room which is 200 square feet will require approximately 6,000 BTU of cooling to condition it properly.
Air conditioners are rated in something called "tonage" and there are 12,000 BTU's per ton. A ton of cooling requires 400 CFM of air to cool properly. If an area is 200 square feet, it would require approximately 1/2 ton which is equal to 6,000 BTU to cool it properly and to properly remove humidity. If it is too large, it will be just as inefficient as one that is too small.
