How to design a smart home to increase energy savings?

Design the system primarily around heating, HVAC, and occupancy control, while treating standby-power switching and automatic lighting as secondary measures; good insulation and ventilation/heat recovery should come first [#12007423][#12050002] Use schedules and presence detection to lower temperatures when occupants are away or asleep, zone rooms that are temporarily unused, stop heating when windows are open, and coordinate heating, blinds, and mechanical ventilation [#11994495][#11997190][#12019210] Avoid disconnecting general socket circuits because many chargers consume only about 0.03–0.3 W, while contactors and the always-on controller may consume comparable power; reserve switched circuits for clearly defined loads [#11993388][#12007423] Measure the automation system’s own consumption before calculating savings: one measured KNX installation averaged about 9.2 W, while a Sterbox example used 1.8 W [#12000258][#11994495] Treat marketing claims such as 23–30% savings cautiously, since results depend heavily on the building, heating system, climate, and occupants; one seven-month test reduced heating costs from PLN 3860 to PLN 3300, with PLN 2305 in components and an estimated 51-month payback before installation labor [#12022258] Keep conventional switches and local control available if the controller fails, and consider rainwater collection for garden irrigation as the only water-saving measure specifically mentioned in the thread [#12007423][#12049718]