I've been told our central a/c unit needs to be replaced to accommodate an increase in the sq footage of our house. Due to this the blower on the furnace will no longer handle the capacity of the larger a/c unit. My question is do I need to replace the furnace to get a larger blower to handle the a/c or can the capacity of the blower be increased? All equipment is Lennox, the a/c is 4ton.