The Impact of Insulating Domestic Houses on the Health of Occupants: an Intervention Study

Damp, cold indoor environments are bad for the health of people who live in them, particularly if they have respiratory problems or are vulnerable, such as the young or the very old. This is a community based study designed to test the hypothesis that insulating domestic houses will make them warmer and that this increase in indoor temperature will improve their health and wellbeing.

Following two pilot studies, the first among older people in city council flats and the second among home owners in Waitara. We have followed the "Waitara model" where community networks will be mobilised to identify households in each community where there is someone with a on going respiratory problem. Seven communities have been selected to help test these hypotheses and have agreed to participate Otara, Gisborne, Mahia/Nuhaka, Taranaki, Porirua, West Coast and Christchurch. Low income areas with high Maori populations have been deliberately selected to maximise the potential health gains.

Two hundred houses in each community will be insulated free of charge to the occupants. The workers who will insulate the homes will be local people employed through the Department of Work and Income (WINZ).

Once the houesholds are selected they will be randomly assigned to intervention or control groups. During the first winter, all 1400 households will be monitored for temperature and humidity and their comfort, health and healthcare utilization will be recorded. Half the households, assigned to the intervention group, will be fully insulated during the spring. The following winter, all the initial measurements taken from both the intervention and control group will be repeated. At the end of the study period, all control houses will be insulated.

This study has developed from a natural intervention being carried out by the Energy Efficiency Conservation Authority (EECA) to insulate domestic houses in New Zealand and is a major collaborative effort, which will shed light on the effectiveness of insulation in improving health and wellbeing. The impact of housing refurbishment on health has not previously been examined. There is considerable government and policy interest in promoting healthy housing and there is strong community interest in ensuring the housing stock is improved in order to lower health risks.