Those changes are nice. I wasn't about to bring up heat frequency relative to day length, but it was on my mind.Anyway, I placed a torch along with a forge so that the torch would force heat updates in F8... which worked.
I can now see that heat for forges is going up. This is good, the problem is not as bad.
So, what I did was I placed 5 forges along with a torch and waited until the heat got over 70%, which didn't take long at all.
Then, I turned off all the forges. What I thought was that maybe dissipation was working too but just wasn't updating in F8 due to the lack of events, like you said. I was expecting it to go down even though the torch would add 1% per minute. This did not happen.
Right on cue, every minute on the minute, the heat just went up 1%.
I waited all the way through until heat reached 100% just in case dissipation occurs less often than heat increase (I waited somewhere around 30 minutes).
If heat dissipation is working, it is not working quickly enough before a single torch makes the heat reach the 100% screamer threshold after this point (70%+).
Checked again with more time (starting with heat around 30%). At some point (beyond 30 minutes) it dropped a few points.
Tested yet again with a single torch and waited over a half an hour. The torch stayed at 33% after reaching 33%. After about 15 minutes, it still was at 33%.
Placed a second torch. Heat started to go up again. Awaiting results. Will it stop around 66%?
EDIT:
Indeed, it did. Added a third torch, will it stop at 99%? I'll find out soon.
I'm guessing it will and I'm guessing anything more than 3 torches is going to cause a screamer loop.
4 torches will mean a screamer every 25 minutes.
So, dissipation works... it's just that for 4 or more torches, it can't keep up. Of course at some point it shouldn't, but the way this is doesn't align with the latest update notes that state we can now place 4 times the torches before worrying about screamers.
EDIT: I was wrong. It went over 99% and screamer spawned. Either 3 torches are already beyond the dissipation threshold, or there is some floating point or rounding thing going on that made it go to 100%. I do not know if dissipation is relative to game day length though. There could be different results. This was checked in 2 hour days.