A landlord’s rising costs or the general cost of living do not, by themselves, allow any rent increase they choose. The increase must comply with the rent-setting rules that apply to your tenancy, including limits, timing and notice requirements, which can depend on the property and when the tenancy began. Check the current guidance on gov.ie and the RTB website, and ask the RTB or a solicitor if you are unsure whether a notice is valid. If you dispute the increase, the RTB’s dispute resolution process will consider the individual facts.