Fuel poverty is the requirement to spend 10% or more of household income to maintain an adequate level or warmth. The energy efficiency of a house can be measured using the Standard Assessment Procedure (SAP). The procedure calculates a number between 1 and 100, low numbers generally indicates a house that has low levels of insulation and an inefficient heating system where as numbers closer to 100 indicate a very energy efficient house. SAP is the Government's recommended system for energy rating of dwellings. SAP is being used as a proxy for fuel poverty in households of people claiming income based benefits, given the link between income poverty and fuel poverty.