Design options for an ageing New Zealand population: A life cycle energy (LCE) analysis

Many elderly New Zealanders live in houses larger than they need and some find it difficult to maintain them. Some struggle on while others prefer to move to retirement villages or similar options. This study takes a typical three bedroom house in New Zealand and shows it is possible to convert this into small units for the independent elderly to enable ageing in place. The aim was to see the resource use impacts of each housing option. Two schemes are shown, one with separate units and a shared entrance and one with separate en-suite bedsits with shared living spaces. The conversions meet the New Zealand Lifemark standards for such housing and provide the type of accommodation found in retirement village units. Seven scenarios were created for households in both the original and converted house. A life-cycle energy assessment of each scenario of the house before and after conversion, including its operating energy and the energy embodied in the building and furniture, appliances, and tools shows that occupancy and design are key factors in whether resources can be saved using this approach. Over 50 years the conversion with 4 occupants showed a 27% saving in life-cycle energy (per person). However, 2 people living in the original house used less energy per person over 50 years than either 2 or 3 people living in the same house converted into two separate units. This is because of the duplication of appliances and furniture and more use of hot water in the two bathrooms. The resources going into converting the house were minimal.