life cycle cost

The indoor climate system, which serves a building with a proper indoor air quality and thermal comfort, has been predominantly designed based on the initial cost. A life cycle approach could improve both the economic and environmental performance. For example, the energy use could decrease. There has been a lack of knowledge, models and simulation tools for determining the life cycle cost (LCC) for an indoor climate system. The objective of this paper is to present a model for calculating the LCC for indoor climate systems. Focus is on indoor climate systems for premises and dwellings.

Assumptions of productivity costs related to the outdoor supply airflow rate and indoor temperature canbe made based on a number of recent studies. A life cycle cost (LCC) computer program for indoorclimate systems based on Swedish conditions was developed and used to compare and optimizedifferent indoor climate systems. A productivity cost related to the outdoor supply airflow rate and theindoor temperature according to the recent studies was assumed.

In Sweden, the activity on building new residences has been decreased for a number of years. The building stock as an average has therefore become older and in the future it will be subject for refurbishment. This paper deals with how to optimise retrofit measures, i.e. how to act in order to minimise the Life-Cycle Cost (LCC) of a building. Insulation measures are emphasised but also other retrofits are dealt with such as changing the heating system. It is shown that the heating system has a vital influence on the optimal amount of extra insulation which is to be applied.