It's coming from the unit inside the house . When BB installed it they didn't install the chime connector, I'm wondering if that would solve the problem. It buzzed by itself only when it's cold, but I also hear it whenever the nest senses someone at my door. The buzzing is loud enough I hear it from another room.
I'm 99% sure that is why it is buzzing. You need to have the chime connector installed and going to the correct wires. It is important to get the gray and white wires on correctly. It isn't hard to do, you just have to pay attention and take your time.
One more question. Why did the Best Buy person not install it? I would think they are all trained on these products and know that have to do that. Installing that chime connector is not really optional if you have a chime in your home. Maybe you could get Best Buy to refund all or a portion of what you paid for the install. Or maybe in today's world with Covid it is just worthing letting go and moving on. 😶
Installing the chime connector worked! Thanks for the help. Don't know why Best Buy didn't install it, plus when I called to ask why it was buzzing they said that was normal! I will be calling to give them a review! Thanks again!