No, you use Irish rules when calculating your rental income and expenses. If the property was available for let for the entire year then you should be able to claim a deduction for your all your variable expenses. If, for example, it was used by your family for July/August and available for rent for the rest of the year, then you should be able to claim 10/12 of the expenses. The key issue is that the property was available for rent and not necessarily rented out. There are restrictions for pre-letting expenses but I don't think you are asking about those.