The zoned attic option is more energy efficient, and a pull-down attic ladder makes access for maintenance easy. You lose a lot of heat/cooling through ductwork, and pushing air through extra space places more of a strain on the system. We live in Zone 7 and have had no issues with the attic unit, which makes use of a small space similar to yours.

I have two Goodman units. One 3 ton for main floor and one 2 1/2 ton for walkout basement. The units were installed new in late 2013. Last year each compressor had to be replaced under warranty. Now the upstairs unit is not cooling properly. The company I purchased the units from is telling me I need window treatments before he can really help me. We have a wall of windows overlooking a lake. I got a second opinion. The 2nd guy is concerned about the pressure readings, 165 on low side and 290 on high. He tried to pump the system down to replace a part and the compressor wouldn't go below 80 psi. He is also concerned that we don't have adequate return air supply for the units. Both air handlers are in the basement area and are tied to the same return air duct. The duct has a 16" diameter opening on one end and a 12" x 12" opening on the other. Do these facts ring any bells for anyone? Thanks JG

so the house is single and split, 1. had furnace boiler heating 2. 5 ton a/c furnace duct system for cooling the ac system was not running great at the farthest of the house ducts (understandable) its about a ~4200 sqft house i want to putt in 2 systems one for the single floor living area 2nd for the split bedroom area in the split bedroom area i was wondering if can do a zoning (damper) without putting in a trunk in the lower level . so 1. one guy wanted to keep the 4 supply as if just increase the size of the arms from 5 inch to 6 inch which i did not feel was enough 2. another guy said he can do the zoning damper but needs to putt in trunk in basement and make ceiling shorter 3. guy said he can do zoning 2 units but will have to figure out where to hide the duct work coming from the attic. I just want a piece of mind that the ducts are properly sized calculated and put in from the beginning because i dont plan on selling the house anytime soon. so figured id do my own homework and have the duct work designed by a professional company and give the hvac contractor the design. because everyone you get tells you i will design as i start the work. so thats what was looking for someone can pay to design the ducts for me in a way that works out to what we are looking to do and be comfortable with. I dont mind paying i understand it is not an easy job.

I insulated the ducts in my basement with the this foil/bubblewrap stuff. The difference was astounding! The basement was the warmest room in the house (3-stories +basement). I knew I was wasting a lot of heat down there. It was really easy to do (don't use commonly misnamed "duct tape", use a foil tape that designed for ducts). The ducts are rigid metal (both rectangular and round), so straight runs, neat seams, and the temperature down there went from the low 80s to 60s. I was absolutely amazed. It's only R-1 or R-2, but it's value is in the reflectivity of radiant heat coming off the metal ducts.