I have a newer Trane 4 ton VS that is H/C 2 rooms down and 2 rooms upstairs. The stratification gets pretty bad when it's gets warmer outside. I have absolutely NO option for a separate system upstairs, there is no room for another unit. The continuous fan helps, but not much.
Right now in the winter, I open the downstairs registers up and close the upstairs registers JUST A LITTLE to push more warm air downstairs. I do the opposite in summer to try and push more cold air upstairs. The T-stat is downstairs by the stairway. It's REALLY obnoxious now that we can need heating and cooling sometimes in the same day (Texas).
Please let me know some opinions on these 3 ideas/solutions, keeping in mind money IS an object, and I don't need anything incredibly fancy or complicated.
1. A honeywell mini-zone zoning controller with 2 dampers 1 up/1 down. If this needs a purge, I want to avoid that. Is it possible to only have dampers close partially? This is pretty expensive, and would be the last resort.
2. A simple wall-switch controlled damper that would close the upstairs air a little when less air is needed up, or open wide when more air is needed. No dump zones, as long as it doesn't close enough to cause overpressure.
3. A wall-dial controlled booster fan that when stopped would act like a slight restriction the the upstairs air, but when running would "steal" more air from the downstairs and push it upstairs. No overpressure, no dump zones.
Thanks to all for any constructive input.