A market rent review is based on what similar properties in the same area are currently achieving, rather than simply on the landlord’s costs or mortgage. Relevant comparisons may include location, size, condition, furnishings, parking, heating and other facilities. The RTB Rent Register can provide evidence of comparable rents, and a rent review notice may need to include specific comparable properties and prescribed information. Whether the proposed rent is lawful depends on the tenancy, applicable rent rules and the evidence available; an RTB dispute process or solicitor can assess the individual facts.