Top critical review
Doesn't quiiiite do what you'd expect
Reviewed in the United States on July 11, 2017
So I live in the southeast, where the summers are brutal and the winters are colder than you'd think. We get wild temperature swings which keeps energy usage quite high during peak months of the summer and winter seasons. Thinking this could help save some costs, I decided to try it. While others have explained a lot about what this system does, let me tell you what is does NOT do.
I was under the impression it would "learn" my schedule (as it advertises it does) and basically figure out that during the week, I work regular hours, as does my spouse. We leave the house within 15 minutes of each other, and arrive home pretty close together soon. So if I leave at 7am, and come home at 5 pm, I want the temperature a comfy 75-76 degrees in my home. The interim? Don't care, which is what I hoped the Nest would work on for me. Ideally, When I leave at 7 or so, it would start to dial back the AC/heat to a decent level, let's say the low 80s, so I could save money, then when it knows I'll be home around 5, it aims for heating/cooling the house back down to an acceptable level for me for when I walk in the door. This thing should be working at my house when I'm away to save me money by not heating or cooling an empty house for a few hours while I'm away, then kicking back on 30/60 minutes or so before I arrive so I walk in to a comfy house.
However, it doesn't quiiiiite do that, you see. I have to do all the heavy lifting as far as keeping it saving me money through the app while I'm away. It has a motion sensor, and a phone proximity sensor, and uses those two things to determine if you're home or not. If your phone leaves a 1 mile radius, or you don't pass by the motion sensor for a period of time, it starts an invisible countdown (anywhere from 15 minutes to 2 hours, though it doesn't tell you how much time, and its not programmable!). After that time, it will starts to let the AC/heat slide in the house to a temperature threshold you set to save energy. Then, it waits until it senses motion or sees your phone again to fire back up. This is a significant issue if you've been away for an extended period, as your house might actually be quite warm/cold when you arrive, but the Nest won't fire up until it "sees" you, meaning you don't walk into a comfy house, you walk into your threshold temperature and have to wait for the Nest to catch up. The motion sensor is also a big issue if you have an older home like mine, and the thermostat is tucked away at the end of a hall, instead of by the front door. Might be a non-issue to some, but be warned if your thermostat is in an out of the way location.
There IS an "early on" feature which lets you set a temperature and time ("I want it to be 75 degrees at 4:30pm"), and let it start heating or cooling your home a bit before that time depending on the ambient temperature. This is a good feature....except somebody HAS TO BE IN THE HOUSE? That makes zero sense to me. Why would I want to have the early on setting on....if I'm already home? Why, if I leave for work, should my wife sit through uncomfortable temperatures if she stays home, only to have it kick on a few minutes before I arrive? This is the feature that is missing from the home/away assist that is absolutely crucial to this being a REAL learning thermostat. This feature DOES NOT work if your home/away assist is on AND sees nobody home, so you're back to walking into a furnace during the summer, when it should realize that every Monday through Friday, I'm home at 5 (give or take a few minutes), and aim to have the temperature at my desired level at that time WITHOUT programming. As it is, you have to turn the main selling feature OFF (the learning schedule, home/away assist) to make it work right.This means manually changing everything if your schedule changes, instead of letting the cool parts of this work, like phone proximity etc. If it turns out I have to call in sick, now I have to go into the Nest software/app, and remove any settings I have for the day, and remember to set them back up so the next Thursday (or whichever day I deleted), I'm not blasted out by extreme heat/cold.
So you CAN program this thing to set the temp throughout the house at specific times.....but that defeats the purpose of spending $200-250 on this thing. It sure looks cool, but I can get a programmable thermostat for a fraction of the cost of this. Why won't the Nest ACTUALLY learn like it says it will? This is a sorely missed feature for those of us who live in areas that get quite warm and cold throughout the year. If they could set it to where the Nest could actually learn the fact I like the temp at 75 degrees, about the time I get home, AND keep the home/away assist stuff on, I'd change my review, but for now, I'm sorely disappointed.