It is for a house in Portugal (where temperatures during the day roughly vary from 15 degrees celsius to 40 degrees celsius), where the walls of the house are 30 cm of concrete, with no insulation at all.
I am going to repaint one room, and I am wondering whether I should make the effort of insulating the outside-facing walls (from the inside) of this room.
30 cm of concrete feels quite big to me. While the walls are slightly cold to the touch right now (winter), I am wondering whether it is worth insulating for the summer. Will that make a noticeable difference?
Best Answer
Just an addendum to the comment. In these screenshots the difference between inside and outside insulation is visualized. Just ignore the red bar for greenhouse contribution.
Everything is the same, only layers no. 2 and 5 were swapped by drag and drop. Layer no. 3 is "glueing mortar" and should be swapped , too, but wasn't.
The R- value is the same, of course, since series R values add independent of the order of layers.
But the important condensate mass and drying time are extremely different. Exactly that is the problem with inside insulation.
To be seen by the blue water drops.
And also the heat storage capacity is better in case of the external insulation.
Whenever possible, avoid inside insulation.
Above is the standard outside insulation with white polystyrene boards.
Beneath is the inside insulation, which can produce mold and health problems.