In this paper, we propose a method for assessing renovation packages drawn up with the goal of increasing energy efficiency. The method includes calculation of bought energy demand, life-cycle cost (LCC) analysis and assessment of the building according to the Swedish environmental rating tool Miljöbyggnad (MB). In this way the methodology assesses economic, indoor environmental quality (IEQ) and specifically environmental aspects associated with energy demand of such packages from a sustainability point-of-view. Through MB, energy efficiency packages are placed in context with other necessary measures required to improve environmental performance in buildings, providing a consistent and systematic basis other than simply financial performance by which to compare capital improvements. The method is further explained and analyzed by applying it in three case studies. In each case study a multi-family building representing a typologically significant class in the Swedish building stock is considered, and for each building a base case and two renovation packages with higher initial investment requirement and higher energy efficiency are defined. It is shown that higher efficiency packages can impact IEQ indicators both positively and negatively and that packages reducing energy demand by approx. 50% have somewhat higher LCC. Identified positive IEQ impacts point to added value for packages that may not otherwise be communicated, while negative impacts identify areas where packages need to be improved, or where MB indicators may be referred to as specifications in procurement procedures.

In this paper three different structural alternatives (wooden frame, solid wood and concrete) for multifamily buildings are compared in terms of global warming potential (GWP) due to material production and bought energy-in-use from a life-cycle perspective using the ENSLIC tool [1]. The work has been performed in the pre-programming phase of a real construction project, aiming at achieving passive house standard and certification with the Swedish environmental rating tool Miljöbyggnad (MB).

The results suggest that the wooden structural alternatives are better in terms of GWP (1.8 to 1.9 kg CO₂-e/m², year) compared to the concrete alternative (4.9 kg CO₂-e/m², year). Having said that, there is considerable uncertainty in key input parameters in the calculation. Firstly, construction contractors in question could not supply standardized data for GWP and lifetime for their structural elements, and a combination of generic data and assumptions were used. Secondly, GWP for different energy sources was not available in such a way that it could be analyzed for reliability.