Originally posted by jcswaim
Thank you for your advise. As for the duct work, what he suggests is to add some more returns and keep the rest the same. They do suggest upgrading to R8. Does that make sense?
Mark is trying to be nice.
It's very unlikely your new system will perform correctly on the old duct system,due to increasing the size,which likely isn't needed .
Read some posts here and think about it before you spend the money.