Looked at a warehouse for my church today, they want to use it as a "storefront/warehouse" church to attract young people to join. 15 cfm for potentially 100 people in a 3200 sq ft space is really going to jack up the tonnage requirements to provide cooling for this space, esp. since the use times are only a few hours a week. This is not really my speciality, but I'm just trying to provide them some advice to guide their decisions. Reading some stuff it sounds like demand controlled ventilation by CO2 sensing would work, but have no idea how expensive that type of system is, plus you would still need the maximum tonnage anyway. Anybody have experience with this situation?