Which tax relief is this?
What is Tax Relief for Mortgage Interest on a Home Loan?
Tax relief for mortgage interest on a home loan is tax relief given to mortgage holders based on the interest paid on a qualifying mortgage on your home i.e. a new mortgage for a home, a top up loan used for the purposes of developing or improving your home, a separate home improvement loan, a re-mortgage or a consolidation of existing qualifying loans [i.e. loans used for the purchase, repair or improvement of your home], secured on the deeds of the home.
http://www.revenue.ie/en/tax/it/leaflets/tax-relief-source-mortgage-interest-relief.html#section1