[quietplatypus]

No one here has yet really considered the real elephant in the room:

Why does anyone need an "intelligent" thermostat, especially something as overhyped and over-engineered as Nest is?

I never even remotely bought into the Nest hype from the very beginning. Ditto on their smoke detectors.

At least, you stop being such a baby and turn the heat up or down by yourself. Controversial, I know.

At most, you put your thermostat on an automatic schedule, which can be done about a thousand different ways (timer circuit, dippy bird, microcontrollers that have already been manufactured and tested in a million different ways by more established companies).

[brianwawok]

So there are some gains. For example if it knows it is an extra sunny day and its 11am, it could heat a little bit less and let sunlight so more. On the other hand, more fancy is more to break.

[discodave]

No, a thermostat already solves that problem because it measures the temperature of the house and adjusts the heat accordingly.

[brianwawok]

Example for the predict temperature component.

For example with honeywell: My house warms up to 70 degrees by 8 am, holds it there for 2 hours, by 10am it shuts off as the sun takes over warming. By noon it is 76 in my house and I am having to open windows to stay cool.

With nest: My house warms up to 70 by 8, but is allowed to drift down to 67 by 10am because it knows the sun is coming. Sure enough it does, and warms up to 73 naturally and for free by noon.

I not only saved 2 hours of running my furnace (8-10 am), I changed my max delta from my desired temperature from 6 degrees to 3 degrees.

[quietplatypus]

Ah, got it. So it's able to take into account outside factors that more efficiently get you to the target temperature. Okay, I see the value now. Thanks for the explanation!