i5, versus i3, versus i7 matters less for fan or fanless compared to the product suffix. That's that letter at the end of the name. U, Y, K, H, etc... Which are decoded on this page: https://www.intel.com/content/www/us/en/processors/processor...
The letter indicate the target application, which then impacts the TDP Intel is targeting (slightly dependent on i3/i5/i7, but maybe not at all). U and Y are the big ones to look at for mobile fan vs fanless. Their definition is:
Y: Mobile extremely low power
U: Mobile power efficient
H: High performance optimized for mobile
TDP (max power draw) based on letter:
Y: 7 W
U: 15 W
H: 45 W
KF: 125 W (unlocked, Requires discrete graphics)
I think most surface pro lineups had the i5 being fanless and the i7 with a fan. And that was a problem, because although the performance difference between the i5 and the i7 wasn't that great (most would not pay for the difference) the cooling differences made it night and day. And as someone who loves passive cooling I was forced to recommend the i7 just because it had a fan. (note: in latest lineup of the surface pro the i5 also has a fan, making the i5 version much more attractive for most (though now it cost as much as the i7 used to do ...))
There is a huge difference in cooling between passive and a very very slight breeze, intel/amd CPUs are a bit too hungry for it to make much sense in the medium-to-high performance CPUs. Though I feel not enough attention is being put into cooling of laptops (passive nor active), isn't a strong selling point I guess (though it should!).