What is the feature of active solar air heating systems?

Active solar air heating systems utilize mechanical components, such as fans and pumps, to distribute the collected solar energy. These systems can indeed be integrated with conventional forced air systems, allowing solar-heated air to augment the heating needs of a building. This integration enhances efficiency by using existing infrastructure while utilizing renewable energy from the sun, making it an effective method for reducing reliance on non-renewable energy sources.

In contrast, the other options highlight features that do not accurately describe active solar air heating systems. The absence of additional components is not true as active systems depend on components for circulation and distribution. Working only at night is incorrect because these systems are designed to harness solar energy during the day when sunlight is available. Lastly, the necessity of ducting does not apply since active systems often require ductwork to effectively distribute heated air throughout a building.