a little too far north for me. The reason I asked is that there are groups and associations that work with churches specifically. You might check in your area to see if there is an association. For example here, there is obviously the Archdiocese for the Catholic Church, and area associations for the Baptist and Methodist Churches. Feel free to check at http://www.mechanicalpantry.com if your looking for any additional information or would like any specific questions addressed. Excellent site for non-partisan assistance.
The only advice is go to a professional commescial HVAC contractor for professional advice. If you need help with your relationship with Jesus you go to a professional (your pastor), so do the same and go to a professional with your HVAC needs.