Estimating a threshold price for CO2 emissions of buildings to improve their energy performance level. Case study of a new Spanish home

Energy consumption in homes produces CO2. In many countries, building regulations are being set to enable energy efficiency performance levels to be issued. In Spain, there is a regulated procedure to certify the energy performance of buildings according to their CO2 emissions. Consequently, some software tools have been design to simulate buildings and to obtain their energy consumption and CO2 emissions. In this paper the investment, maintenance and energy consumption costs are calculated for different energy performance levels and for various climatic zones, in a single-family home. According to the results, more energy efficient buildings imply higher construction and maintenance costs, which are not compensated by lower energy costs. Therefore, under current conditions, economic criteria do not support the improvement of the energy efficiency of a dwelling. Among the possible measures to promote energy efficiency, a price on CO2 emissions is to be suggested, including the social cost in the analysis. For this purpose, the cost-optimal methodology is used. In different scenarios for the discount rate y energy prices, various prices for CO2 are obtained, depending on the climatic zone and energy performance level.