No general exemption applies simply because a landlord owns or lets only a small number of properties. RPZ rules depend on the dwelling and tenancy, although specific statutory exemptions may apply, such as where a property has not been let for a qualifying period or has undergone substantial change. The applicable rent-increase rules can also depend on when the tenancy began and later legislative changes. Check the current guidance on gov.ie or the RTB website, and consider speaking to a solicitor before relying on an exemption in a particular case.