Principal reasons for underoccupation are where children have grown and left the family home, or where a spouse has died or left. Underoccupation is a complex issue, with often good social reasons for not moving to a smaller property. Older people in particular tend to rely on strong local community networks, and these links can have real health and other benefits. This issue is discussed further in Annex A . The likelihood of ill health is increased by cold homes, with illnesses such as influenza, heart disease and strokes all exacerbated by the cold.
Cold homes can also promote the growth of fungi and numbers of house dust mites.
The latter have been linked to conditions such as asthma. Ill health can lead to enforced absences from work, and certain types of illness such as respiratory disease, may restrict choices of employment for those people without work. The need to spend a large portion of income on fuel means that fuel poor households have to make difficult decisions about other household essentials. People in these higher risk groups are found in more than half of UK households. They are also likely to be at home for more of the day, possibly all of the time, so that heating is needed for more of the time than in other households.