Current Revenue guidance says a self-contained unit can qualify only if it is within the home, such as a basement flat or converted garage. It also says that if the unit is not attached to the property, it cannot qualify for the relief.
That means detached units do not currently qualify under the published Revenue guidance. The April 2026 government announcement says the Minister for Finance will consider tax arrangements for auxiliary dwellings and Rent-a-Room interaction through the normal Budget and Finance Bill process.
Until that text is published and in force, homeowners should not budget on detached garden-unit income being relieved in the same way as a room inside the main home.
Short-term leisure letting is also outside Rent-a-Room relief under current Revenue conditions. This site does not promote short-term guest accommodation as a tax-relief strategy.