The amount of the basic subsidies contemplated in the PREE Program for actions in buildings as a whole will be 35% of the eligible cost for all types of actions, except in the case of energy efficiency improvements in lighting installations, where the subsidy will be 15%.
In the case of the rehabilitation of dwellings or individual premises within buildings, this percentage will be 25% and 15%, respectively, with the possibility of different additional aid depending on the use of the building and whether energy efficiency criteria, social criteria or integrated performance criteria are met; as regards social criteria, the Royal Decree establishes that those actions carried out in residential buildings that have been definitively classified under a public name. Protection Regime and in residential buildings located in Urban or Rural Regeneration and Renovation Zones. will be entitled to additional support.
If you are carrying out a project in Spain, this is an interesting point to analyze.
In this link you can find more information.