How much does floor construction affect the case for a whole-system setback?

A slab’s slower response would make me cautious about deep setbacks: it may take a long time to recover, so a smaller change - or none - could feel more predictable. A lighter assembly may make setbacks easier to live with because it can respond sooner, though the result still depends on the system. With one shared boiler target, changing it affects every calling zone, so I’d favor letting thermostats manage room schedules and adjust the common target only if it suits the zones together.

If one zone needs heat again much earlier than the others, would you keep the shared boiler target steady and let that zone’s thermostat call as needed? I’d be more inclined to change the common target when the zones’ schedules broadly line up, and leave it alone when one zone’s comfort or timing would make the change inconvenient for the rest.

I’d weigh comfort and predictable recovery more heavily than a possible saving if a setback leaves a slow floor taking too long to feel comfortable again. Modest setbacks seem like a better compromise when they’re comfortable; deeper ones would only be worth considering if the savings were meaningful enough to justify the wait.