'HVAC Contractor Practice Exam 2025 – The Complete All-in-One Guide to Exam Success!'

The primary purpose of duct insulation in an HVAC system is to prevent condensation and energy loss. Insulation plays a crucial role in maintaining the temperature of the air traveling through the ducts. When air travels through uninsulated or poorly insulated ducts, it can lose heat in the winter or gain heat in the summer, leading to energy inefficiencies and increased utility costs.

Additionally, when warm air passes through cold ducts, it can cause condensation to form on the exterior of the ducts. This can lead to moisture problems such as mold growth or corrosion, which can further impact the HVAC system’s performance. Insulated ducts help keep the air at the desired temperature, thereby minimizing energy loss and avoiding condensation issues, which ultimately contributes to a more efficient and effective HVAC system.

The other options focus on different aspects that are not the primary purpose of duct insulation. Increasing air pressure, filtering particles, and decreasing humidity are important to overall HVAC performance but are not directly related to the main function of duct insulation.