How to manage one heat zone with two thermostats

heater

Main house: forced steam/radiators with a simple programmable thermostat.
Addition (large family room): forced hot water baseboard with an old-school dial thermostat.

But there is only one zone. When you turn up the heat in the addition, all of the house radiators heat up and heat the rest of the house. It's absurd.

Having just moved into this house and do not have money to burn, I'm looking to determine what – if anything – I should do to make this arrangement the most efficient. Just put a programmable thermostat in the addition to time things correctly with the main thermostat? Just accept the fact that I need to crank the heat in the addition for warmth and that the rest of the house will be warmer than I need or want?

Thoughts? Thanks

Best Answer

With one zone, there's only one thing that can be controlled by a thermostat: how much hot water is pumped through that zone. For example, if your main house is a little cold, there's no way to add heat to the main house without also heating up the addition (and vice versa).

If you're ruling out adding more zones, or somehow adding controllable radiators, then all you can do is balance out the heating effectiveness between the two areas. It sounds like for a given level of heat, too much is pumped into the main house relative to the addition. So, you need to either a) increase the effectiveness of the radiators in the addition, or b) decrease the effectiveness of the radiators in the main house. My guess is that you'll have to do b), which you can do by closing radiator louvers, blocking the air path, etc.

If this is done properly, and you don't change the heating needs of one space relative to the other (e.g. don't leave the addition's front door open) then you may be able to get the temperatures to be at least close to each other.