Ever since I got my Nest thermostat, I thought it was really cool and saved me a ton of energy when I wasn’t home. Plus, with the introduction of Google Home, I was able to control my thermostat with my voice. Well, those are great things but did you know installing Nest voids warranty on most HVAC heater/AC systems?
Recently, my heater electric ignition module broke and cost me $400 to fix. The funny thing is that the HVAC technician’s first question to me was, “do you use Nest?” It was as it he knew Nest was causing a lot of problems. Before he left, he told me that he replaces electric ignitions and 9 out of 10 times, the home owner was using Nest thermostat. Specifically, my old house uses 2 wires for connecting to my heater and according to the technician, this is causing the ignition module to fail. Now, if you are using 3 wires with a common wire, you won’t have this problem. But my house uses 2 wires and since Nest powers itself through those 2 wires, it can cause havoc on the ignition module. Since there is no common wire, Nest must be powered through the 2 wires and also this is used to signal the heater to turn on.
Now, I cannot prove that this is exactly the problem scientifically but from what the HVAC technician told me, I think it can be true. There are numerous articles on the internet where people are having problems with Nest and having no common. Obviously an easy fix is to add another wire but on an old house like mine, that may become a big hassle. Also, Nest VOID WARRANTY on most HVAC systems, check out this reddit article here. If you’ve just installed a brand, new heater or AC, you may want to double-check that you don’t void warranty by using Nest. There are many other alternatives to Nest so you may want to consider using them instead.
As for me, I have replaced my Nest with a simple, battery-powered thermostat since I really don’t really use Nest’s features too much. And if you are thinking about using Nest, definitely keep in mind the 2-wire problem and voiding your warranty before buying. Otherwise Nest may end up costing you more money in the long run like it did for me.
A good alternative would be Honeywell WiFi thermostats, which are also cheaper than Nest.
(Interesting to note that Honeywell advertises their products on Amazon w/ “C Wire Required”, must be something that does cause problems a lot.)