The answer to 'what does zone control system do' is a zone control system allows you to independently control the temperature and airflow in different areas or 'zones' of your home. This gives you greater control over your home's comfort and energy efficiency, as you can heat or cool only the rooms or areas that are in use.
Zone control systems use multiple thermostats and motorized dampers in the ductwork to regulate airflow to each zone. This allows you to set different temperatures for different areas of your home, such as keeping the bedrooms cooler at night and the main living areas warmer during the day. This can lead to significant energy savings compared to a single thermostat controlling the entire home.