We have a split level house, single furnace, that has 3 heating zones. Each zone has it’s own thermostat. We’d love to install programmable thermostats. Can I go buy 3 $25 units from the hardware store, or are there thermostats specifically needed for this set up?
Need more data. You say a gas furnace, but how is the heat distributed? Forced hot air, hot water, base board radiators, radiant heat?
Forced air. The ducting splits just after the furnace, which is where the zone controller is.
I suspect that what you have are 24 volt thermostats (I have a split level with three zones and that is what I have). These are the most common and you should not have any problem getting programmables for these. The only alternative (I think) for your system would be something called a “millivolt” system. These are a lot less common but you could still find programmables.
If you look at the “zone controller”, there should be a transformer which will tell you what voltage you are dealing with.
I am not an expert, just a homeowner.