Re: Heating/Cooling Return Air Question
Unfortunately you have a less than desirable setup with only one return to begin with and located on the second level and doesn't sound like it's sized properly. In reality there should be a return in every room that have supplies run ( excluding bath rooms )
Adding a return(s) definately sounds like what's needed in the lower level to balance the static pressure. Putting the return in the ceiling isn't the ideal location since it will draw out the warm air -- that naturally rises -- out of the room. It also depends where the supplies are located -- if they are also up high then having the return high will create a short circuit of air flow not allowing much warmth getting down to floor level. If the return(s) can be located down toward floor level would be benificial.
"" an ounce of perception -- a pound of obscure "