The second UI was a lot simpler. No rotating sprites, in fact no sprites at all. A simple graphic that is white for showing the current temperature, turns red when adjusting up, and blue when adjusting down. Same as before, tap on the left side of the screen to adjust down, right side to adjust up or center to view current.

Current in center, desired temp in circle at top right.

Temperature adjusted up

Temperature adjusted down

I haven't gotten around to adding the alternate screen to the new design.

My next step is to find a 3.3V or 5V relay that I can easily control via GPIO to turn the furnace on or off.