I recently am looking into getting a rooftop unit for a 1200 sq ft one flat store front in the westside of chicago. It is being used as a youth group with at anytime 20-40 people in it. I had a couple of people come in and recommend me a 3 ton unit but then one came in to tell me a 10 ton unit would be necessary because of the extra heat generated by the people. DOES THAT SOUND RIGHT? Any advice? Thanks for any input you can give me.