Since December, I have been using the "circulate" setting on my tstat for the HVAC fan instead of auto. It turns the fan on every few hours and circulates air through the house. I felt like it made a difference, both in comfort and in using less heating/cooling, but I really had no way to judge or measure. I think I have good data now.
My Honywell tstat sends me monthly reports on hours of heating/cooling per month and compares them to the same month in the previous year, including average inside and outside hi/low temps. Of course most of the time you can't really use that annual comparison because you don't have consistent monthly outside temps. For this May though, it showed I had the same hi/low average outside and inside temps as May 2020. While the extremes and times might affect accuracy, this is probably as reliable a comparison as I'm going to get.
This May, using circulate, I had 46 fewer hours of heating and 8 fewer hours of cooling than May 2020. I believe this was mostly due to using the circulate feature. Especially on the heating. I like to use my wood stove a lot, but from where it is, it mostly heats the living room / kitchen areas. I think "circulate" helped send that heat throughout the house, especially to my bedroom. Also I have a bonus room upstairs that of course captures rising heat, and I think "circulate" helped redistribute some of that air to the rest of the house. For cooling, May doesn't really get hot, and in fact my first May here there was even a little snow, so the lower "saved" number makes sense.
Anyway, it looks like whatever extra electricity that "circulate" uses to run the fan is more than offset by less HVAC use.