I wonder if I could pick your brains? I'm a contractor/carpenter in Ma. I've been presented with a question from a HO. They are interested in moving air from the 1st floor (radiant heat source) to the second. Tried fans with limited success. I actually have a similar situation in my own home.

I've thought about this for some time, talked to many, and the best I could come up with is an in-line fan in a ceiling joist bay with a vent above (second flr floor vent) and a register below (1st flr ceiling). Probably 6" vent. Any concerns, ideas? Has anyone done this? Do you think it will move enough air to make it worth it? Ant fan products you would recommend/stay away from?

I'd also like to hide/blend the ceiling register. Empty recess can; speaker trim?

I've yet to talk to anyone who has tried to solve this problem. I find it hard to believe due to the recent popularity of wood stoves/high price of oil. I'd appreciate any feedback. Thanks in advance.