I have an old White-Rogers thermostat with only 4 wires coming out of the wall and need to replace it but the only new ones I find (at Home Depot) have 5 wires. How do I hook up a 5 wire thermostat to 4 wires and still have it work properly?

Big John

It would help to tell us the colors and what they are hooked to on the old tstat
What are the posts labeled on the new tstat also
Sometimes there's a need to tag the wires befire removing from tstat

OK, sorry I didn't provide all that with the original question. There is a Red, Green, White and Yellow wire, all attached to appropriately labeled posts. This all suddenly became academic a few minutes ago when my wife came in with a "new" thermostat that she liked and it has four wires -- same colors and it has been installed, works fine and best of all, she's happy with it!

Thanks so much or your response and effort. I promise to do better next time!

Thanks again

Big John

Good deal, glad you got it going,glad you made the little woman happy. That's number 1 priority