How to install

Httow to change from round thermostat to a programmable honeywell thermostat

What type of heating system do you have? Not all tstats work on all systems. Do you know how many wires come out of your wall going to the old stat, colors too if you know them.

I just read your other post. Still answer my question in post #2 but also read this http://customer.honeywell.com/techlit/pdf/PackedLit/69-2448ES.pdf