Which characteristic describes All-air systems?

All-air systems are specifically designed to provide both heating and cooling by delivering conditioned air throughout a building's space. This type of HVAC system draws air from the environment, processes it to achieve the desired temperature and humidity levels, and then circulates it internally via ductwork. The conditioned air ensures that the indoor environment remains comfortable regardless of external weather conditions.

The delivery of conditioned air allows for better control over indoor climate, providing a single solution for temperature regulation, which is essential in both residential and commercial settings. This characteristic sets all-air systems apart from systems that rely solely on water for heating or cooling, or those that combine different mediums like air and water, or utilize electric resistance for heating. Such distinctions clarify the functional scope and methods of operation for all-air systems in the context of HVAC technology.