[dolbz]

I hope there's an override for auto-away. Imagine going away over Christmas and your pipes freeze because there has been no heating at all... Not a problem in California where this has been developed but a realistic problem in much of the world.

[harshaw]

Yeah, there are some counter-intuitive things you need to think about with baseboard heat and very cold temperatures in New England. Normally it is just fine and dandy to let your fancy thermostat drop the temps to the high 50s at night except when it is 10 degrees outside - in that case you want to turn up the temperature so you don't freeze your pipes :) Sadly I speak from experience.

[stereo]

I suppose it simply keeps the temperature above freezing even when you're away, like most thermostats

[_delirium]

That's not sufficient for many home designs, though; you may need to keep the interior temperature into the 40s or 50s to keep the pipes in the wall above freezing, depending on the outside temperature and your house design. One reason the default "away" temperature for many thermostats is actually pretty high, like 55 or 60.

[mturmon]

True, and just "learning" your regular day-to-day habits would not necessarily inform the system about an absolute lower bound on temperature.

I think the thermostat control problem is harder than I might have given it credit for. Any time you have to learn in a nonstationary environment (http://mathworld.wolfram.com/NonstationaryTimeSeries.html), nasty surprises can happen. The future may not look like the past.

[Corrado]

The manufacturer mentions that it has a link to the web and can consult weather forecasts. This should allow it to kick the heat on if the forecast calls for freezing weather and your not home.

[nitrogen]

The first section of their information page (click "Meet the Nest..." in the middle of the landing page) suggests that an absolute min/max temperature range is programmed when the thermostat is first installed.