Which of the following is a potential source of HVAC system inefficiency?

Dirty filters are a well-known source of HVAC system inefficiency because they restrict airflow through the system. When filters become clogged with dust, dirt, and debris, the HVAC system has to work harder to pull in air, which can lead to reduced airflow, decreased system performance, and increased energy consumption. This not only affects the comfort of the indoor environment but can also lead to premature wear and tear on the equipment. Regularly replacing or cleaning filters is essential to maintain optimal airflow and efficiency in an HVAC system.

In contrast, properly sealed ducts, regular maintenance, and programmable thermostats are all factors that contribute to system efficiency. Sealed ducts help to ensure that conditioned air reaches its intended destination without leaks that can waste energy. Regular maintenance ensures that all components of the system are functioning correctly and helps to identify and address any issues before they lead to inefficiencies. Programmable thermostats allow for better temperature control and can optimize heating and cooling schedules to reduce energy usage when the space is unoccupied.