There are two methods, stop the heat getting in, or absorb the heat which gets in, thick walls can help, I know in the 80's when I lived in Algeria we tried all sorts with our workshop, the accommodation had AC's but not our workshop, bricks to allow an air gap, and tin sheets helped, best was to try and grow grass on the roof, until some one worked out how much water we were using.
But as we move to warmer countries there is a tendency to use flat roofs with access, so solar panels can be maintained, and the peppers dried out. (That was Turkey) In the main there was not much free space on the roof, solar panels heated the domestic hot water.
But what is more important is what are the Spanish rules? They seem to have a different method of charging for electric, more like our commercial method, here in UK we have 60, 80, or 100 amp supply, and standing charge same for all, but in some countries it is charged on the peak use, it was limited with a fuse, so going over for a short time was OK, but with the advent of "Smart Meters" going over for a very short time can either get fines or disconnection.
I know this happens in France, not sure about Spain, so a UK forum is really not the place to ask, as there system is so different, here we do have split phase supplies to remote farms, but not village homes, but it is common in other countries, we see imported cooker hobs designed for split phase.
