InterNACHI Home Inspector Practice Exam 2025 - Free Home Inspector Practice Questions and Study Guide

The addition of more insulation in areas where insulation already exists, such as in the attic, typically helps to reduce energy bills. This is because insulation serves to slow down the transfer of heat between the interior and exterior of a building. By increasing the insulation thickness or density, the building becomes more energy-efficient, meaning it can retain heat in the winter and keep cool in the summer more effectively.

As a result, homeowners will rely less on heating and cooling systems to maintain comfortable indoor temperatures. This reduction in reliance on HVAC systems leads directly to lower energy consumption, which in turn results in decreased energy bills. It is important to ensure that the insulation is installed properly and the R-value (a measure of insulation’s thermal resistance) is sufficiently increased to reflect meaningful improvements in energy efficiency.

Other options, such as increasing energy bills, having no effect, or eliminating them entirely, do not reflect the general principle of how insulation works. Thus, the best understanding is that adding insulation directly contributes to cost savings on energy bills.