Larry, from Excalibur, came to my home to install my Nest smoke detector. He advised me to combine the thermostat and the smoke detector to reduce my energy costs, and in case of a fire my air conditioner would shut down. And he took the time to set up my cell phone with the Nest app and showed me how it worked. He was very professional and patient. I felt reassured I had the right installer, as it was very clear to me that Larry knew his stuff. He also was a very nice guy. I was very impressed, indeed.