I don't know what we can do. We already have a roll down sunscreen. Painting the house white is not something that will be accepted by the neighbours.

Though it depends on the particulars of your house and garden, there are ancient techniques -- "rediscovered" by modern permaculture -- that are effective here. Plant dense, deciduous shrubs and trees along the southern side of the house, especially in front of windows. The shade and the evaporative cooling provided by them should help to keep the house cooler in summer, whilst still allowing sun to heat the house during winter.

It's not as effective as air conditioning, but it's more sustainable, certainly.

Houses in Spain have stone floors, instead of carpet or wood that we often have in Netherlands. Maybe you can switch depending the season