Cost reduction of the new NZEB Wooden building – case study of the kindergarten in Estonia

Tallinn University of Technology, Nearly Zero Energy Buildings Research Group, Ehitajate tee 5, 19086 Tallinn, Estonia

^* Corresponding author: endrik.arumagi@ttu.ee

Abstract

In this study the cost changes caused by the implementation of the nZEB solutions are calculated. The energy demand of a building was calculated according to the methodology for calculating the energy efficiency of buildings, using dynamic energy simulations. The financial calculations are based on the methodology described in Delegated Regulation (EU) No 244/2012 of the European Commission. The simulations and calculations for assessing the cost-effectiveness of technical solutions are based on the selected sample building. The energy efficiency solutions are derived by increasing/decreasing the insulation value of the building envelope in subsequent steps. Financial calculations were based on the investment needed to achieve the nearly zero-energy levels. The results for different combinations vary to a large degree. According to regulations new building must fulfill the low energy building (EPI class “B”) requirement without local production. The EPI value to fulfill the requirement in the cost-even range is reached in case of the GSHP and efficient DH. In case of the GSHP and efficient DH also the cost-optimal point is in the EPI class “B”. Overall the minimum ΔNPV values stay below the zero line in all the cases offering a range of opportunities to choose combinations to reach lover EPI compared to base case. The results of cost-effectiveness calculations for selected building with different combinations of structural solutions and heat sources show the possible different scenarios to reach nZEB level and the possible cost reduction.