I have been informed that if you are purchasing your property with a view to making it a rental business then you can claim 70% of the IVA back. I don't know all the details as it doesnt apply to ourselves but it may be something that interests others.
Seems this is based on the fact that IVA is the equivalent of VAT. In this sense if yiu are renting out and paying due tax to the Spanish I.R. then you are equally eligible to claimback your IVA. It also applies to any IVA (VAT) you pay in Spain for anything associated with the lettings etc Electricity.
Don't have anymore details.
Christine