Windows can lose a lot of heat in buildings, but thermal shutters can help reduce this. Using Vacuum Insulation Panels (VIP) in shutters can make them much more energy efficient. A study compared VIP insulation to regular insulation in window shutters and found that VIP greatly reduced heat loss. The biggest factor affecting shutter performance was thermal bridging, which can be improved by reducing heat loss through the frame and walls. VIP insulated shutters performed about nine times better than those with regular insulation.