Changing the furnace fan speed can have an impact on both the temperature and moisture content of the air in forced air heating systems. Here's how it can affect each of these factors:
Temperature: The fan speed plays a role in distributing the heated air throughout the space. When the fan speed is increased, more air is circulated, which can result in more even temperature distribution throughout the area. However, increasing the fan speed alone does not directly affect the temperature of the air being heated by the furnace.
Moisture Content: The moisture content of the air is influenced by the relative humidity. In a heating system, the air is typically drier than the desired comfort level. The operation of the furnace fan can affect the humidity in the following ways:
Higher Fan Speed: Increasing the fan speed can lead to enhanced air circulation, resulting in increased evaporation of moisture from surfaces and occupants. This increased evaporation can make the air feel drier, potentially reducing the relative humidity.
Lower Fan Speed: Conversely, reducing the fan speed decreases the air movement, which reduces the evaporation rate. As a result, the air may feel slightly more humid, and the relative humidity may increase.
It's important to note that while the fan speed can indirectly influence the moisture content by affecting the evaporation rate, the primary means of controlling humidity in forced air heating systems is through the use of a humidifier or dehumidifier, if necessary.
Ultimately, changing the fan speed alone will not significantly alter the temperature or moisture content of the air. The main purpose of adjusting the fan speed is to regulate the air circulation and improve overall comfort by achieving better temperature distribution within the space.