The floor insulation plays an important role in saving energy of the whole building. One way to insulate floor is using underfloor heating together with Synergy XPS insulation boards. In this method, Synergy XPS boards are installed on subfloor which is usually made of concrete. Then the heating systems and its different layers is installed on top. This way the heat produced by the heating system is traped inside the room and is not wasted. Finally the final layer which can be any material such as wooden floor tiles and stone tiles is applied. This system can also be installed in old buildings that need renovation. In this case the floor must first be cracks isolated and evened out.