The residential sector was accountable for the consumption of 143 TWh in 2007, comprising35 % of Sweden’s total final energy use. The City of Stockholm has high ambitions in the environmental area. Miljöhuset is a web based energy calculation tool that helps to manage energy use, choose energy and cost efficient measures as well as present the environmental impacts of a building. This study had the aim to analyze the energy calculation tool from a scientific − and userperspective and to suggest potential further improvement of the tool. This was done in two maindirections: The first was to examine issues related to the tool itself such as user-friendliness,environmental impacts presentation, results transparency etc. The second direction was to explore potential future development possibilities for Miljöhuset and the possibility of using it asa support in energy declarations. The educational aspect of the tool was examined too, by attempting to identify whether there is a possibility for Miljöhuset to be utilized for this purpose too. In order to examine the aforementioned issues, a Stakeholders Opinion Assessment (SOA)method was used: 18 persons representing 18 different stakeholders answered a questionnaire and gave an interview. Through this procedure, it was possible to identify strengths and weaknesses of Miljöhuset and analyse stakeholders’ opinions on the same. The findings of this study are that Miljöhuset has a good user interface and a holistic approach towards the operation of a house by integrating economic, environmental and energy aspects into one tool. Furthermore, the participants’ perception is that Miljöhuset is understandable and itsvalues/parameters relevant. However, improvements will be necessary in order to increase itsacceptance. Such improvements include both user friendliness and accuracy of the results. A number of stakeholders that are interested in the tool have been identified and further discussions were suggested in order to specify the type of interest these stakeholders expressed. A morethorough discussion and analysis of suitable future target groups would be valuable since future development should be tailored to them. Such an analysis could also more clearly define the potential of Miljöhuset as an educational tool or as a support in energy declarations. The possibility of whether or not the introduction of a fee for Miljöhuset would be beneficial hasbeen studied. The results did not allow drawing firm conclusions about this aspect, however, and further research is suggested. Finally since there are other tools that fulfil similar functions as Miljöhuset, further study about the competition in the web based energy calculation environment is also suggested. / <p>www.ima.kth.se</p>