UPDATE: Nest released a firmware upgrade that adds some cool features - most notably you can see exactly when the HVAC unit is running and what made it run (weather, user changed temperature, away from home, etc.) This addresses some of the "blackbox" issues I noted below. Although I do long for more detailed operating data, like I could get with ecobee, this update is a huge improvement.
Pretty much everyone needs to take a hard look at their home's thermostats.
Heating and Air Conditioning account for more than half of a typical home's energy bill and most families don't do a great job managing HVAC energy use. The concept of a programmable thermostat has been around pretty much forever, but the systems are rarely set correctly and in all of the places we have lived, the thermostats have been left at the Energy Star recommendations (and sometimes operating in temperature hold mode). Texas electricity bills average $2000 per year, so HVAC savings make a tangible difference.
Operating at the defaults is better than operating on "hold," (the EPA suggests a 20% energy savings) but it's possible to wring quite a bit more savings out of the system and to be more comfortable by programming the system to meet your family's needs. The challenge is that traditional thermostats aren't intuitive to program or adjust on the fly.
Fortunately there is a new generation of thermostats designed to help. First ecobee and now Nest are available to help manage your HVAC intelligently. I've had ecobee for several years and will write about it soon.
Nest is new and until recently has been hard to find. It is interesting because it takes a different approach to thermostat design and energy management -- it's basically a very attractive "black box" that displays little information, supposedly all you need to know: set temperature, current temperature and when appropriate, how long it will take to reach the set temperature and a "leaf" icon to help guide you into making energy-wise choices. Things like "time of day" are deliberately left off of the screen.
Although it's possible to program Nest's schedule on the device, or via web or iOS device, Nest is designed to learn based on your actions. Are you too cold? Turn up the heat. Going to bed? Turn down the heat. After a week, Nest learns your preferences and will begin to set the temperatures automatically. Not comfortable? Change the temperature and Nest will eventually learn the preference. The temperature adjustments get instant feedback on the screen -- the leaf indicates an energy efficient choice and requests that require more energy give a brighter red or blue color.
So, how well does it work?
Pretty well. We adjusted each of the three zones controlled by Nest everyday based on our comings and goings and after several days of this, Nest began managing the temperature setbacks itself. The first schedules were close to what I would have programmed myself, so there's no additional savings there, but what was different was that people began adjusting the Nest to make themselves more comfortable. It was here that the interface really shined (literally, I suppose). The color and leaf feedback kept the adjustments low -- often a degree or two at a time and I think this ensures the best balance between energy conservation and comfort.
The extreme simplicity of changing temperature using the control wheel is satisfying and people like to use it. This completely sets Nest apart from any other programmable thermostat, including ecobee, with its somewhat finicky touchscreen.
So, what's not to like?
If you like data, Nest will drive you nuts. Its features (or at least the way they are applied) are mostly undocumented This contrasts significantly with ecobee, which has minute-by-minute recordings of HVAC activity, inside and outside temperatures and more available on your personal page on their website.
Nest is also limited in the types of systems it can control, but Nest does have a helpful compatibility check to let you see for yourself.
Nest is $249, which is expensive, but I figure it will pay for itself in less than a year -- basically by the end of the Summer.
So, should you get Nest?
If you're not a geek, then yes, I think Nest is a good choice that is also aesthetically pleasing. If you are a geek, then maybe ecobee is a better choice. Consider your family first, though. If they're not into the technology like you are, look again at Nest.