Bought an old 3-storey house in Maine, heated with gas forced-hotwater radiators. There is only 1 zone, with the thermostat in a 1st floor front room with little traffic and away from any radiator.

When the t'stat calls for heat, it takes so long for it to register at the t'stat site, that the house ends up heating up by 5 degrees or more before the t'stat shuts it off. Since the hot-cold fluctuations are especially large on the 3rd floor (usually it's too cold up there), I had my electrician string a temporary t'stat cable up through the central chase to the 3rd floor, where I attached another t-stat after disconnecting the 1st floor t'stat. Guess what -- now the first floor gets too cold (remember -- only 1 zone!)

Obviously the dynamics of heating and resonance are complex. So, I wonder if it ever makes sense to install more than 1 t'stat? Can it be done -- in parallel, I mean? I'm using a RiteTemp digital. I'd like to use 2 or 3 of them, all with set-backs. I'd appreciate some expert opinion of this idea. Thanks.

With only one zone, anyone of multiple thermostats can turn the heat on. The heat will stay on until all the thermostats shut off. This may cause over heating in some areas. If you have more than one loop. There may be balancing valves you can adjust to give more uniform heat. Look for valves near where different floors branch off.

Would it be possible to install electric duct heaters to the 2nd and third floor and control them by the thermostats? Im not very familiar with the way they install heating systems up north.

Wheat...

No ducting! It's all done with water pipes and radiators. (Which means there's far less drying of the heated air, but also no possibility of central humidification.)