There’s the typical HVAC installation — and then there’s the installation that’s not so typical, more than interesting, and requires a unique application. The ones that happen in a flight simulator facility where outdoor temps dip below -20 F; or in the conversion of an Amish barn to a family home; or in the renovation of a city landmark, like a Brooklyn limestone townhouse built in the 1800s that offers very little space to install a payphone, let alone an entire HVAC system.