In Ireland, a tenant who believes a rent review is invalid can generally refer the dispute to the RTB within 28 days of receiving the rent-increase notice, so check the RTB’s current guidance promptly. The RTB will ask for evidence such as the notice, tenancy agreement, correspondence and comparable rental information, and may offer mediation or proceed to adjudication. A valid notice must also meet the applicable rent-control rules and notice period, which is generally 90 days. An adjudication decision may be appealed to an RTB tribunal within the specified deadline; the outcome depends on the facts of the tenancy.