I rarely use the attic fan these days. The basement is nice in the summer.
(Still use the basement fan, if the Radon gets too high).
We keep it dehumidified and the slab is cool enough that's it's comfortable down there. The attic fan could be moved upwards a few feet. Not enough to cut the noise much. (My wife dislikes the woody smell of hot attic air).
As for the winter, the slab is does most of the basement heating (~50F), so we try not to go down there without a jacket.
A small amount of additional heat down there comes from the oil burner runs, which are controlled by Alexa to minimize oil use.
Since my three 200 watt PV panels weren't doing anything, I hooked up that 600 watts to a resistive load to make a little heat. I think it runs about 500w in good sun. 1700 BTUh, that has very little effect on the basement, but it might be keeping the floor near my chair in the dinning room about 1/1024th of a degree warmer.. Maybe placebo effect heating.
Anyways, my wife and I are getting really old. I've got RA in my hands and feet so bad that I should be living in SW Texas, instead of north of Boston.
So going down to mess around in my shop or ham station, isn't what I want to do in the winter time.
I looked over all those posts, and found the heating numbers so low, they were depressing.
The only really successful thing about this project is the basement fan is great for removing Radon..
Cheers,
Rich