I am in the process of finishing my basment, and have decided that the HVAC (among a few other things) is one of the tasks that I want to leave to those with the proper tools and know-how. However, the one contractor that showed up to quote the work told me that a return duct was not necessary in the basement. I'm hesitant to believe him - the first and second stories in my house each have them, and it would only make sense to me that balancing the pressure from the three additional vents that I'm adding would be necessary by adding at least one additional return. Who's right?
The basement is approximately 500 sf and will have one bedroom (~120 sf), one bath (~80 sf), and an open game room (~300 sf).