I recently updated a 9x14 foot outbuilding on our property to function as a darkroom and while there are a number of benefits to being completely separate from the main house (beer cave of solitude!), not having a heating/cooling system to tie into is a bit of problem. It will soon be 100+ degrees here in Tucson and I need to figure out how I'm going to cool this building. As I see it I can either use a traditional window air conditioner (the building does have two windows) or I can get a stand-alone portable unit that vents to the outside via a hose. Obviously my two biggest concerns are keeping the room light-tight and well ventilated. Does anyone know if a window ac unit (the unit itself) lets light in? It seems to me that a stand alone unit with a vent hose will be the easiest to install and keep light-tight. Has anyone used one of these units in their darkroom space?

There's also the issue of ventilation, currently I draw in clean air from the ceiling and vent out (via a fan) above the darkroom sink. As I don't want the AC unit to draw in fumes across the space I'm working in, I'm thinking it would be easier to have a portable stand-alone unit that I can freely position in the darkroom to avoid this circumstance.

If anyone has experience heating/cooling an outbuilding/darkroom I'd be interested in hearing your solutions.