An EPC certificate consists of an assessment of the energy efficiency of the property. The property is attributed a rating which varies from A to G - the most efficient is A and the least efficient is G. The EPC inspection takes into account the building's age, type of fabric, thickness of the walls, levels of insulation, type of windows, lighting, heating system and its controls. The EPC survey does not take into account your appliances, such as washing machines, microwaves or any heater that is not fixed. The energy performance certificate lasts for 10 years, and all properties on the market for sale or rent do require a valid EPC.  You can check whether your EPC certificate has expired on the government EPC register: https://www.gov.uk/find-energy-certificate