Why is insulation important in a building's energy performance?

Insulation plays a crucial role in a building's energy performance primarily because it minimizes energy loss. By acting as a barrier to heat flow, insulation helps maintain a consistent indoor temperature, regardless of external weather conditions. When insulation is properly installed, it keeps warm air inside during colder months and prevents heat from entering during warmer months. This efficiency leads to reduced reliance on heating and cooling systems, which in turn lowers energy consumption and utility bills.

In comparison, while the size of the building or its architectural design may have some implications for energy performance, they are not the primary functions of insulation. Insulation specifically targets energy retention and efficiency, making its role essential for achieving optimal energy performance in any building.