Which of the following statements is true regarding HVAC systems?

HVAC systems, which stand for heating, ventilation, and air conditioning, play a crucial role in maintaining indoor comfort. One of their key functions is indeed to manage humidity levels, along with temperature control and air quality. This capability is essential for creating a comfortable and healthy indoor environment, as high humidity can lead to issues like mold growth and discomfort, while low humidity can cause dryness and respiratory problems.

Managing humidity involves controlling the moisture level in the air, which is particularly important in varying climates or seasons. HVAC systems typically include components like humidifiers and dehumidifiers to help maintain the desired humidity levels, making them versatile beyond mere temperature regulation.

In terms of other choices, HVAC systems do more than just control temperature, they can operate on multiple power sources (such as gas, electric, or other fuels), and they require regular maintenance to ensure efficiency and longevity. Proper maintenance includes tasks like changing filters, cleaning coils, and checking refrigerant levels, highlighting the systems' complexity and the need for upkeep. Thus, being able to manage humidity is a fundamental characteristic of HVAC systems, reinforcing the choice as the correct answer.