Which of the following is a common symptom of inadequate insulation?

Inadequate insulation is often indicated by increased energy bills. When insulation is insufficient, heat can escape during the colder months, and unwanted heat can enter during warmer months, leading to the HVAC system working harder to maintain the desired indoor temperature. This increased workload directly translates to higher energy consumption, which is reflected in the energy bills.

In contrast, high air quality, improved indoor comfort, and consistent temperature distribution are typically associated with adequate insulation. Adequate insulation helps regulate indoor temperatures effectively, enhances energy efficiency, and can minimize drafts and fluctuations, all contributing to a more comfortable living environment and potentially better air quality. Therefore, improved insulation would not lead to increased energy bills; rather, it would help decrease them.