In properties with two or more floors, you should bleed downstairs radiators first.
Begin with the radiator situated furthest away from your boiler or central heating system. (Also start with this radiator in single-storey homes or bungalows).
You should bleed hot water radiators on at least an annual basis. There’s more tips and advice on how to do so safely in our full Advice Centre blog, How to Bleed a Radiator.