but the click is caused by a relay in the thermostat closing. This is what "tells" your system to start. The mechanical relay we use actually costs us more that a silent electronic switch, but it is far more reliable. If you want total silence, up grade to the VisionPro IAQ; it's relay is on the control unit that goes in your mechanical space.
However, if the stat is clicking more than once for on, and once for off, something is wrong in your system.
Has anyone else had customers complain about the little clicking noise when the thermostats turn on? I have been using the Honeywell 5000 and 6000's and do admit they make a little click when they turn on and off. My customers say it wakes them up at night. Is my only option to go back to a mercury type stat or are there other brands or honeywell models that work better?
Some of the Totaline (Bryant & Carrier) models are electronically switched and silent. From Honeywell, the Vision Pro IAQ has the relays in the equipment module in the equipment room so the wall unit is silent.