Having some minor problems with our new geo install, not specifically related to the geo aspects but seemingly more of general HVAC duct sizing/type/installation issue. With all the general HVAC pro's on here I'm hoping to get some opinions on a way to proceed. General system info: WaterFurnace 7 Series with IntelliZone2 and 3 zones. HVAC system duct plan can be viewed here. Zoning is broken down into: Master Suite, Balance of 1st floor, and 2nd floor. The first floor zones work great, the system has no problem maintaining the temperatures. The systems ramps up and down as needed and I've yet to see a compressor speed over 8 (of 12) even as the exterior temperatures dip down to 10F or so. The second floor however has been a constant problem. Although set at 68, it regularly drops to 64 or so at night when the outside temperature drops anywhere below 30 or so. This should not be an insulation (walls R-18 flash & batt closed cell spray foam, attic R-64 combination closed cell spray foam and blown fiberglass) or infiltration (scored 1.5ACH50 on our blower door test) issue. I believe the problem is a combination of the following issues: 1. The flex duct installed in the attic is only isulated to R-8 (standard for the area) and in my opinion poorly installed. I can see a number of kinks where the suspension straps are installed, or where they cross trusses. 2. Long duct run. The 10" x 10" riser up from the basement to the attic is long by iteself, even before the 10" and 8" flex duct runs in the attic. 3. Variable speed system. Because the 7 Series is variable speed it generally cranks itself down to a low level where it runs all the time. This means that the 2nd floor zone is rarely running by itself, resulting in even lower flows due to the backpressure of the long run. It seems this should have somewhat been covered by the Manual J/duct sizing calculations. 4. Because the flow to the vents is low and are not very well insulated the air coming out is fairly cooled by running through the uninsulated attic. The installer has brought out a vent hood meter and verified that each vent and return is moving some air (numbers are way lower than I'd expect, but I don't know what they should have been). I'm debating two possible paths forward. A. Reroute all the flex ducts to elimate kinks and shorten routes where possible. Lower them to the top of the spray foam and then mount blown fiberglass around them to improve insulation. B. Rip out all the flex ducts and replace with rigid ducting in the attic, using some combination of insulation to get them up to closer to R-25 or so. C. Something else I haven't thought of yet. I'm happy to provide any other info I might have if it helps in assisting with a solution. Thanks in advance.