Other tweaks
For some reason (likely to cut corners), the layer fan and the electronics fan in the Creality 1.1.5 mainboard are wired together, sharing a mosfet.
This is, in my opinion, quite ugly so instead I hardwired the stock electronics fan to a +12V source from a step-down converter. Since this fan is 24V rated, supplying it with 13-14V produces a nice airflow while still being relatively quiet.
The extruder fan is way too loud for my taste. Replacing it with a 40x40 Noctua worked wonders. As this is a 12V fan, I have it attached to the same step-down regulator I mentioned earlier.