I am planning on building a large enclosed (Cartesian XY-Head) 3d printer. I want to keep the inital build time minimal and it is very likely I would need to build the ~50x50cm heatbed from scratch, because it doesn't exist in ebay. The enclosure itself is not separately heated, but depends on waste heat from the printing process. The enclosure will eventually be vented outdoors with a 12V CPU vent via ducting (air flow unknown).
Do I even need a heated print bed, when I am planning to only print PLA?