Mould and Winter Indoor Relative Humidity in Low Income Households in England

This paper examines the extent to which variation in heating-season, indoor relative humidity (RH) and mould occurrence in English households is explained by dwelling and household characteristics. It is based on analysis of data from a national study of England's Home Energy Efficiency scheme ( Warm Front) which provides grants for energy efficiency improvements to vulnerable households. Surveys were undertaken of dwellings and households participating in the scheme in five urban areas. Half-hourly living room and main bedroom temperatures and RH measurements were recorded for two to four weeks in a subset of dwellings (no.=1604) over the winters of 2001–02 and 2002-03. For each dwelling, regression of indoor vapour pressure excess on outdoor temperature was used to obtain estimates of daily living room and bedroom indoor vapour pressure under standardised conditions (outdoor temperature of 5°C and 80% RH), from which standardised values of indoor relative humidity were derived. We present evidence on the relationship between mould severity and standardised relative humidity, and between both these parameters and household and dwelling characteristics, including Warm Frontimprovements.