Improvements do not automatically give a landlord the right to increase the rent. In a Rent Pressure Zone, a landlord may be able to rely on an exception where substantial works have significantly changed the nature of the accommodation, but routine repairs, decorating or replacing worn items would not usually qualify. The landlord must still follow the applicable rent-setting rules and serve a valid written notice within the required timeframe. If you believe the increase is unlawful, check the current guidance on gov.ie or the RTB website, and consider seeking advice from a solicitor; any dispute would ultimately be decided under the RTB process.