Residential HVAC Installation Practice Exam

An oversized duct system can cause the air to slow down as it flows through the ducts, which can lead to issues with proper air distribution and comfort levels. This can also result in increased energy costs and reduced energy efficiency. While reduced noise levels may be a potential benefit of oversized duct systems, it is not the common issue that arises. Similarly, increased airflow speed may seem like a desirable outcome, but it can lead to uncomfortable drafts and uneven heating or cooling in a space. The most common issue with oversized duct systems is the slowing down of air, making D the correct answer.