I give this product one star for the first item, which was ultimately resolved by a second unit. If I could give negative stars for Nest as a company, I would give them a -10. If you keep reading, you may not want to purchase this item in the first place. **Warning: It is long, but trust me... you want to read it!**
I bought two of these for both zones in my home. One worked flawlessly and calibrated itself within minutes. The other one, however took more than an hour to calibrate, which after calling Nest Support, they claimed was normal since they verified it was wired properly. Something, however told me that it wasn't normal, but I accepted the word of the expert on the phone. Eventually it calibrated and started blowing warm air like it was supposed to since it was winter. It seemed to take a little longer than normal to reach a warm temperature and we noticed it would turn on for what seemed like no reason, but thought it just must be a super sensitive product that would keep the air temp. precisely where it should be, so we ignored that as well. As the seasons changed and we got hit with a particularly warm spell early in the Mid-Atlantic, the A/C never turned on. In fact it was still blowing warm air even though it said it was "cooling".
I tried trouble shooting and eventually went through the entire set-up procedure again to no avail. I called Nest Support and the woman on the phone was very pleasant, but told me to disconnect a wire that the previous agent had told me was installed properly. She also told me to leave this wire disconnected since it caused the unit to begin to blow cold air as it should. Okay, I will once again accept the advice of the "expert" and do as I'm instructed even though it goes against that gut feeling that it was wrong. I was just thankful to have cold air again.
The next day I go to work and get a call from my neighbor telling me that my A/C unit is making strange loud noises. When I get home, I hear the crazy sounds coming from my unit and the upstairs is hot. Really hot! Immediately shut it off and don't bother calling Nest at this point. I get a real A/C tech over to check my system. He tells me that my Nest was sending too much voltage to the unit and fried my "contactor" which switches between hot and cold. He replaced that part, put the Nest back on line and wouldn't you know....same issue occurs. He removes the Nest, puts a different thermostat on (also a learning system) and it worked perfectly. Then to show he wasn't trying to sell me anything, he took that down and put my ORIGINAL thermostat back up and again it worked perfectly. He told me I was lucky because a few more hours of use could have completely destroyed my A/C unit, then I would be looking at several thousand dollars to replace it.
I explained all of this to Nest Support and finally they agreed to send me a replacement Nest since I still wanted to use their product. A few days later I received it, installed it and it calibrated itself in less than 10 minutes. Surprise, surprise. AND it worked right the first time. So what would you do if you had this happen to you and your gut, your technician and the experiences all pointed to Nest damaging your A/C unit? Right! You would call them and request that they pay for the replacement part. You might even demand that they pay for the labor and appointment fee as well. I didn't though. I only asked them to pay for the part! A $165 part. That's it.
Here is where the trouble really gets stupid and frustrating. This whole thing started in April. I was put on hold, promised call backs, transferred to multiple "specialists", ignored, insulted by argumentative language and then ultimately dropped from their radar all the while thinking I was getting somewhere. Two days ago on June 22, I could take no more and called and demanded to have the issue resolved immediately. I was not going to be promised a call back or to leave a message. After being transferred and hung up on, eventually I reach another "specialist". ONE HOUR LATER.... I was told my request was denied. Then she argued with me for requesting them to take another look and gave her the WHOLE story again. She said and I quote, "Ma'am, if you want me to submit this to our senior management again, it will be denied".
Enough. I give up. The Nest was defective and damaged my unit. That is 100% clear, honest and factual and even Nest knows this because they gave me a new unit. Nest support is garbage and will NOT support you when they are at fault. Buyer beware for sure! Do yourself a favor and ask technicians first if they have any issues with them before you trust your very expensive A/C unit to this thermostat. You will be surprised. What they don't tell you is it is NOT always compatible with your unit. You will NOT know this unless you ask them. Then they will reluctantly tell you. Good luck and you have been warned!