just had a certificate done for our farm we are selling. cost 300 euros. The sq mtrs of the house, size of windows, if double glazed or not, how many doors you have, how high the ceilings are and if you have insulation are all taken into consideration to reach the rating. Who knows if anyone will care about the rating, but it is compulsory for all property if you want to sell a property, or rent it out. I think Spain have been dragging there heels on this as it has been law in Uk for quite a while. :D