During construction of two surgery centers in Tennessee, I endured the installation of an inadequate HVAC system not once, but twice. On both occasions, we spent more than $100,000 to retrofit the facilities with HVAC systems that would let my surgeons work in comfort during the dog days of summer or winter's deep freezes. I paid overtime rates for crews to make the changes on weekends so the ORs could remain open during the week. The thing is, I approved systems that matched the specs suggested by mechanical engineers. And yet neither turned out well. And therein lies the paradox: The problem with designing HVAC systems is that inadequacies arise only after the facility opens. Hopefully, you can learn from my mistakes.