I'm wondering if they provide any meaningful savings vs a cheap programmable thermostat. Putting your HVAC on timers so it runs less will obviously save energy, but can Nest actually do much better than a unit from Home Depot?
When you're running the AC, it actually learns how long it can continue to cool by just running the fan due the the lingering coolness of the coils after the compressor has been running. This causes the AC compressor to run less while you're still able to be kept cool, at significant cost savings.
Your standard thermostats currently don't do this.
Well... the really cheap ones are just timers/thermometers. The amount of control you have over it is related to how much you can program it. I used to have one that was very simple: I could set 2 times/temps for the week and 2 for the weekend. It was easy to program but didn't have much smarts. SO on days that I worked form home, it still let it get hotter/colder for my pre-programmed "away" time frame. So I was constantly tweaking it when I was not really away. My new house had some fancier ones that gave me more times/temps to program and I think I could adjust them per day (not just "week" and "weekend") but it was actually overly complicated to program. And some of the fancier ones still cost $150-175 at HD. So at $250, the Nest is not that much more expensive than some of the fancier ones at HD. But you get some much more "smarts" with it. And you get all the cool extra stuff like remote access, monthly usage reports, habit learning, etc.
> I'm wondering if they provide any meaningful savings vs a cheap programmable thermostat.
In my experience, yes. I left town for two weeks and forgot to turn on away mode. If I'd had a cheap one, I'd have paid for two weeks of A/C keeping my house at 72. Instead, I was able to remotely tell it to let the house get up to 85 before kicking in.
Auto-away does the same thing on a smaller scale on a near-daily basis for me, as well. We've got a pretty unsettled schedule, so it's a wonderful feature.
