Answer by
LeheckaG (1826)
To save energy/money:
Caulk/Insulate wherever cold/heat is leaking (like around doors/windows);
Set your HVAC-system's-thermostat to OFF or to minimal-levels (to keep pipes from freezing)
when your-building is unoccupied for long-periods-of-time;
Get an-indoor/outdoor-thermometer and an-electric-fan,
and Take advantage of outside-weather
(ventilate when it uses less-energy).
Upgrade to a multiple-thermostat/"zoned" HVAC-system;