What is the opinion of Reddit about the
PTC Car Fan Air Heater, 100W 12V Energy Saving Constant Temperature Heating Element Heaters for Heater Humidifier Air Conditioning Appliances?

seen these? I’m in a similar boat where it’s usually sunny and not overly cold during daytime.

https://smile.amazon.com/dp/B07MDN81C3/ref=cm_sw_r_cp_apa_fabt1_g6BVFbE1P4CDJ

I’m going to use one of these, aiming it towards some rocks bound up by chicken wire. Going with an arduino controller to turn it on based on temperature.

I used this design with some modifications: https://www.thingiverse.com/thing:4356645
With this PTC heater: https://www.amazon.com/dp/B07MDN81C3/
And this controller: https://www.amazon.com/dp/B07K68JJY1/