I bought a house in March '11. It has dual zone heating running off baseboard (AC is run through vents off the upstairs programmable thermostat). The downstairs zone is an old thermostat that I was hoping to replace with a programmable. When I pulled it off the wall it had two wires attached. I went to Home Depot and the sales person said a programmable only works if there's three wires. My friend, an electrician, said that's not true and two wires would suffice. I've tried researching the web to no avail. I was hoping someone here would be able to help?
Your help is greatly appreciated in advance!
Edit: not sure if this should go in here, please move accordingly.