The yurt is a tough place to heat, the temperatures are volatile, after all it is just a fancy tent. The temperatures are now more stable that during the first week of the Nest. I can see that the Nest still claims to be in "learning mode" when it comes to learning how long it takes to raise the temperature. So I'm hoping it will get better. Right now, it is clearly better than if I use a regular thermostat and just leave the stove on high all the time. I'm enjoying not having to set the heat level myself.
Could it be even better? Yes, I think the strategy that Nest is using will not ever get to the point of best possible heating for the yurt. The Nest seems to favor staged startups and abrupt shutdowns. In cold weather, I can see that starting on stage 1 isn't going to gain ground in heating, but Nest has to try before graduating to stage 2 and stage 3. When it achieves its target, it abruptly shuts the pellet stove down. The puts the yurt temperature into freefall. Once Nest determines that it has to start the stove again, it has to go through the stages again even though stage 1 is demonstrably insufficient and lets the temperature fall even further.
I'd like to try that reversed: start on high, get the room up to temperature quickly, then ramp down until a stable state is found. If I can't find a way to get Nest to do this, then I will build another circuit that will do the staged shutdown automatically. This is the TTL circuit that I refer to in my blog posting.