I have an older 2 story house with sub-optimal air distribution. We get supply air everywhere but only have 1 air return. Electronic dampers open and close to send air upstairs, downstairs, or both  

In new construction you would generally put an air return in every room so that as conditioned air 
is supplied to the room, the old air can be removed - making heating or cooling a more balanced tradeoff. 

Our single return is somewhat centrally located. It is located on the main floor, in the stairway connecting both floors.

What do we do in a heatwave like we’re having right now? Close the damper for the downstairs supply (sending all air upstairs only), keep all the doors open upstairs, and allow the main floor return to circulate stale air from upstairs as best it can. 

It’s actually working quite well.

aspiring everything. architect. building /buildings. icbk.me/huugo.fc

I’m also surprised at how little people know about airflow management.