There is a free DVD listed on SchoolFacilities.com and it has a 13 minute video clip that every teacher, parent and school administrator should see. This will make you think twice about the HVAC system before you order your next portable classroom.
I was lucky enough to witness the testing of a new HVAC system for modular classrooms installed on a trailer in California a few months ago and it was really quiet. The difference from the old unit to the new would seriously improve the learning environment.
You can request the DVD here.
