The Double Wall Insulation System

Dear readers, after having talked you about the Scandinavian houses last week, I would like to think with you about how important is the insulation system of our house.

Starting from the fact that some air exchange is inevitable, the aim of insulating is reducing the airflow, maintaining your house the warmest possible in winter and the coolest possible in summer.

To let you understand with numbers, the inevitable air volume exchange varies roughly from 0,2% to 0,4%: this means that a 3.000 sqm house with a 9 foot ceiling and therefore a volume of 27.000 cubic feet, will exchange from 7.700 to 15.400 cubic feet of air in 24 hours.

Insulating your house is essential also to maintain in perfect conditions your walls: indeed, without insulation, the continuous exchange of cold/warm air would lead the wall to mold or creating mushrooms and other parasitics bad for your health.

mold

Imagine all those nasty bacterias living around you and making your house smelling so bad :(!

The most efficient way to insulate your house is the “Cavity Walls”: it consists in two skins separated by a hollow space (cavity). This method has been introduced in Europe in 19th century, and is used up there to insulate houses, even in the Norhern Countries.

The material used to insulated are generally absorbing materials like mineral wool, granules or foamed insulants: they absorb the cold coming from outside and passing through the first layer of wall, in the way that the more internal layer of the wall remains warm. The opposite is for the summer, when the Double Wall system helps to maintain the house fresh.

Hence, insulating is really important for the summer too! How good is the feeling of stepping into our fresh house while outside is +40? And all this without even spending in air conditioned, if the insulation is done well! Think how much your energy bill would be lower, during summer and winter ;)!

Obviously, the absorbing material, becomes wet because of the  trapped humidity, and is fundamental that the wall is aerated, so it can dry and not mold.

The perfect insulation aims to reduce Thermal Bridges, which are the points where a penetration of the insulation layer by a highly conductive or non insulating material takes place between the interior (or conditioned space) and the exterior environment of a building assembly.

cavity_wall_diagram
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Insulation around a bridge is of little help in preventing heat loss or gain due to thermal bridging; the bridging has to be eliminated, or even better, not created :)

Dear readers, if you are about to build your own house, think seriously about the insulation aspect, because is what makes the difference :)!

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