thermostat settings

Homeowner

I have a programmable thermostat designed for my steam heating system. Is it more economical to program the thermostat lower at night and when I am away during the day or leave it at a set temperature? It seems like it takes an awful lot of energy to reheat the water, pipes and radiators after they get cold.
Thanks,
Steve

Mike T., Swampeast MO

You just described...

...one of the paradoxes of setback.

The paradox of time: setback only results in less fuel consumption if the space is MAINTAINED at the lower temperature for a sufficient length of time to offset the increased fuel required to raise the mean radiant temperature of the space (even forced convection does this).

The other paradox...

The paradox of temperature: The greater the difference between the temp outside and the temp inside the more energy it takes to raise the temperature.

So...

The longer the period of time for setback the deeper the setback temperature.

BUT, the colder it is outside, the longer the time required to achieve true fuel savings.

The general accuracy of the temperature control affects the time paradox considerably while the level of insulation affects the temperature paradox considerably.