One of the main points that are observed in the heating and cooling needs is thermal conductivity of the structural elements of the building. The most modern way to increase heating and cooling efficiency in buildings is preferably to use "insulated material”. PVC is one of these materials. Coefficient of thermal conductivity of PVC is 0:13 kcal / m² h ° C. In the table it is still clearly seen that metals are materials with high conductivity. Therefore, according to the Decree of the Ministry of Public Works of October 30, 1981 the use of metal in joinery in Turkey was banned.

With the use of PVC:

• the heat loss from the window reduces up to 30-35% as compared to wood and 25-39% as compared to regular aluminum.

• In the heating plant especially the radiator area and group is reduced, the boiler is narrowed and the heat and plant material is reduced. The double-glazed maximum insulation values of other materials can be read in the table.

• When used in Penextra Thermopane window system, the insulation value of 2.5 W / m² K is a value that far exceeds the standard value that is acceptable in Europe.

• The heat savings with the Penextra Window System is 46%