Anti-Insulation can make buildings use more cooling energy after adding insulation. This can be a big problem in the building industry. The study looked at why this issue is often ignored. They found that not calculating internal heating loads properly is a key reason. By testing different insulation materials in a cold climate, they found that internal insulation saves more heating energy, while external insulation saves more cooling energy. Polyurethane insulation is best for heating, while Glass-wool is best for cooling.