Ive been following this forum for quite a while and decided to jump in. To begin with I am a homeowner and not a HVAC dude but we recently purchased this 2 story home in the San Fernando Valley (hot summer, cold winter). It was built in the 60's and still has the orgional HVAC system, Gaffers & Sattler. One monster single zone that blows through soffit downstairs and the rest gets pushed up through the attic to the rooms. Lets just say by the time the air gets to the furthest upstairs bedroom, the air is barely cool and the air blasts through vents downstairs. Its the most inefficient unit, if you go out and watch the electric meter when that unit fires up, you would swear the dial that spins on the meter is going to fly right off and shoot through that glass protection.
So here is my question. 4000 sp foot home, 2000 top, 2000 bottom. I know calcs need to be done but the real question refers to the ducting. When its replaced, would it be better to try to figure a way to push all the ducting through a soffit downstairs and have the upstairs vents in the floor and downstairs vents in ceiling? This would significantly shorten the duct run to upstairs and it would be in cooled soffit vs. through baking attic in summer. The house is about 50 ft long so running the duct through the soffit would make the run less then 50 feet but through the attic it would be about 16 feet up the side of the house then into the attic(hot) and then all the way across the attic (50').
If running both pipes through the soffit for upstairs and downstairs, and they are side by side how do you get the offshoots past each other that go off to the vents in the floor for upstairs?
This is the first post and I hope to over time figure this out before committing to an install. And maybe through this a good honest HVAC recommendion will slip out for the San Fernando Valley.
Last note as to brand recommendations???
I look forward to hearing from all the expected wide variations in advice.