I'm looking at getting a new furnace & a/c to replace my old units. One room of my house receives very poor air flow, even though it has 4 registers, and is only about 300 sq feet. I've had a couple of techs (who have serviced my units in the past) say part of the reason is there are several 90 degree angles the air must go thru b4 it reaches the room. In addition, 3 of the walls in this room are exterior walls, so needless to say the room stays too cold during a Nebraska winter. One tech said when I replace my 4 ton furnace with a new one of the same size, I use a 5 ton blower on it to try and push more air. Any thoughts ?