||08-24-2013 08:57 PM
Your system may or may not have capacity to accommodate that area. The CFMs in a system are sized for the size of the rooms.
To get you started, here is a step-by-step calculator. http://www.ehow.com/how_5677999_calculate-cfm-hvac.html
Now, you need to know what your system is generating and if you have the capacity to do the job. Calculate all the loads ... add the new load. Look at your plate and check out the comparison.