>>2930600in spain is mostly EWI too, at least in the layman mind is the only well know option
in the old times it was mandatory or at least super common for the buildings to have cavity walls, so you can fill them like picrel
they drill holes in your wall to the cavity wall and blow insulation inside it, its a single afternoon job. if done from the outside you dont even have any mess on your house
depending on how the cavity is, how thick and many other parameters, you will get better or worse results, or may not be able to do it properly, but when possible is the cheapest, by far, like half of the price of interior insulation?
random video in english https://youtu.be/6EIXb9SSHqA
you can /diy/ with a cheapo ash vacuum machine, if it can be used to blow but it would be easy, but as far i know you dont save that much bc the material is not easy to source if you dont work on this
>>2930610both material and labor is cheaper on the inside, for one you dont need anything that needs to withstand the weather nor you need scaffolding, and there is the fact that you may be renovating the interior walls anyway. and if you need to do a new electrical installation the fact that you make a new drywall makes shit way cheaper too
as far i remember insulating in the interior was like 60% of the price of the equivalent ewi
Some of us live in places protected, yes, and i would prefer insulating on the outside, but you dont lose that much space, if you compare with the space you need for the heaters, storage for blankets etc, as i said you dont get many of the benefits unless you go all in
like in my case, going all in i dont need to care if my water lines freeze in winter when i am not there, bc they wont, but if i go only with the money optimal insulation i will need to care about that,and trust me is a recurrent problem where i have the house