In this 21st century the comfort has been essence in the modern life. To live in comfort we need  favorable conditions like fresh air circulating inside the building, good average temperature irrespective of the weather etc. New laws on consummation of energy oblige us to make maximum utilization of energy provided  i.e. we may not be able to buy as much energy as we wan, it is costly on the other hand.

Now we started building low energy consuming housing which is only possible by proper insulation of building and using solar panels.  Insulating in general sense means to make a structure water-proof. We must know solar energy released by sun in a day is quite enough for the world for entire year.To gain a title like of high environmental quality structure we should pay very a careful attention to such subjects which demands a careful study on related topics.

In addition to insulate a structure  we need to cover a structure by a materials which has a good thermal resistance. In market we can have so many materials. However in limited budget we can’t do whatever we like because it demands a good calculation behind. If we use less insulation, condensation can take place inside the structure (which means there is big difference of temperature between two surfaces) as we can see in the classical buildings. A proper choice demands a calculation. However the commonly used insulation materials are rock wool( laine de roche in french), glass wool (laine de verre in french) ,extruded polystyrene (fr: polystyrène extrudé) etc.  Below is one example of rock wool used in building insulation.