If insulation gets wet, what effect does it have on the insulating character of the insulation?

When insulation gets wet, it tends to decrease its insulating character. This is primarily due to the fact that moisture in insulation material can significantly increase heat transfer. Insulation works by trapping air within its fibers or cells; air is a poor conductor of heat, which is what makes the insulation effective.

When insulation absorbs moisture, the trapped air is displaced by water, which is a much better conductor of heat. As a result, wet insulation cannot effectively resist heat flow, leading to an increase in energy loss and a reduction in the effectiveness of the insulation. In certain situations, prolonged exposure to moisture can lead to additional issues such as mold growth and degradation of the insulation material, further compounding the loss of insulating performance.

Thus, the decrease in insulating character due to wet insulation is a critical concept to understand in HVAC systems, emphasizing the importance of maintaining dry conditions for effective thermal performance.