I've been thinking about getting a 'smart' thermostat since the first time I heard they existed. The appeal to me is the ease of turning down the termostat when leaving for the day. I have no faith in the thermostat to learn my routines but I'm ok with doing it manually via my smartphone. The big question is, 'do you really save energy or is it somewhat evened out by the recoery time?'
The consensus is (based on the laws of thermodynamics) you'll save energy for every minute your thermostat is set back, not much but some. So I've only had it a week or so and I'm trying to set it back any chance I get, but the recovery time is significant, and the savings in the best case scenario are not that significant if I'm only doing a one degree set back here and there.
Overall I like the termostat (Ecobee 3, in Ontario Canada there is a $100 rebate available to most people, link, Google your area you might have a rebate too).
In all my hours of looking into this I came across two interesting things.
1) When you drop the temp your humidity goes up (condensation), so you can be introducing moiture into your house (risk of mold) if you do a huge setback while on vacation. Most people don't seem too worried about the mold and I haven't heard any horror stories, but it's something I hadn't thought of.
2) I came across a great slide show that compares the impact of different energy saving activities. Things like setting back your thermostat, insulating your attic, all the way down to keeping your fridge full (even with water jugs when low on food) so it's not cooling so much air. I like to do as many as I can but I don't stress about it if I don't have time to do some of the lower impact ones like keeping the fridge full of water jugs, especially now that I see how little of an impact it has.
Click here for the slides
Here's a link to the site I found it on
p.s. I came across one more interesting thing, studies showed that most people didn't use the features of their programable thermostat when those became popular because they were too complicated to set. Hopefully the default settings of these new smart thermostats do a bit better of a job and make a bit of an impact. I found the Ecobee to have many more settings and features than I thought it would, but the final state of it is not far off the default settings, 1 degree setback for when I'm sleeping or when it notices no one is home.