Hi, I'm brand new here and looking for some advice on a huge investment. We live in Southern California and have a 12+ year old 3 ton Lennox system on our house and the original furnace, a 35 year old Carrier. We've been getting estimates to replace the whole system and just had duct work and registers replaced 2 years ago. Right now our furnace is in the uninsulated garage and the cold air intake is on the wall in the dining room next to it. We can hang meat in the summer in the rooms near the garage, but at the end of the house where the bedrooms are, they are usually 4+ degrees warmer or colder, depending on season. We are considering moving the furnace to the attic, we've been given estimates from reliable companies and they all say that it is a good idea for our house because that will place the blower and cold air intake in a more central location for better efficiency. What's your take on this?? Also, 2 companies said they can just make modifications to our 2 year old duct work and 1 company said they need to redo all the duct work because elbows weren't put at all the registers, etc. We are feeling overwhelmed by the amount of info! Help!