Your technician, Chris, was very knowledgeable, helpful and courteous.
On a related subject, we followed Chris's advice on getting a thermostat that sends warning emails to us and you when the temperature in the house falls below a predetermined level. We have two thermostats in the house, and we want the new one installed on the first floor. The thermostat that's currently on the first floor should be re-installed in place of the one that's upstairs because the former is considerably newer than the latter and has more features. Thanks for your attention to this.
Alice and John Huff