I have four of the round Honeywell thermostats in our house built in 2005, three for zone heat and one for A/C and zone heat (#T87F 2873 3). Ours has the mercury bubble unlike some of the newer ones that are mercury-free. None of them maintain the temperature settings very accurately. For instance there were times when the thermometer on the thermostat showed 3 degrees below the setting but the heat would not come on; at another time the temperature might be 3 degrees above the setting but the heat would not shut off. My main thermostat is off by about 6 degrees but that varies from time to time. Sometimes the heat or A/C comes on and goes off 6 degrees from the setting, other times it is just a couple degrees off. We had the builder replace the A/C thermostat but the replacement acts pretty much like the first one.
The list price of $70 (as seen on an Amazon seller site) for the non-electronic thermostat is very unreasonable. None of the parts are made of material worth more than a few cents. I may be showing my age but it doesn't seem like too long ago when the round thermostats sold for $5.
The round Honeywell thermostats do last a long time because there is hardly anything in them to go wrong. The electronic thermostats that I've had in former houses have nice features but seem to last only a couple years before malfunctioning. Lightning or power surges or poor design must do them in. I give the round thermostats 2 stars at least because they last a while, though in my case, not very accurately.Get more detail about
Honeywell CT87N1001 The Round Heat/Cool Manual Thermostat, White, Large.
