Mixed air is a combination of which two types of air?

Mixed air refers to the air that is created by combining return air, which is the air that has already circulated through a building and is being drawn back to the HVAC system, with outside air, which is fresh air that comes from the outdoors. This process is vital for maintaining indoor air quality and temperature control in various spaces.

By mixing return air and outside air, the system can effectively balance the indoor air quality while utilizing some of the conditioned air, thereby enhancing energy efficiency. This blend helps maintain proper ventilation rates and temperature, ensuring a comfortable environment for occupants.

The other options describe different air combinations but do not accurately reflect the standard definition of mixed air in HVAC systems. For instance, stale air refers to air that has been sitting in a space without circulation, while fresh and exhaust air implies a focus on air outflows rather than the reintroduction of air back into the system. Conditioned air relates to air that has been treated for temperature and humidity, whereas ambient air indicates the surrounding atmospheric conditions. Each of these combinations serves different purposes in climate control systems but are not what is typically referred to as mixed air within the context of HVAC practices.