Multi-criteria assessment approach for a residential building retrofit in Norway

This paper presents a multi-criteria assessment approach for a wide range of energy efficient measures and their combinations applied for a residential building retrofit in Norway. A number of passive, active and renewable energy efficient measures (EEMs) have been selected and defined. Based on the level of energy saving potentials, these EEMs have been combined into 18 retrofit combination packages (COMBs) and grouped into various retrofit levels (Moderate Retrofit-I, II, III and Extensive Retrofit). The annual primary energy consumptions (heating, hot water and electricity) for the proposed combination packages were simulated in IESVE building energy simulation software. This is then followed by two levels of assessments: i) the comprehensive assessments of the key retrofit priorities including primary energy reduction, global costs, payback period and the carbon emission reduction and ii) social assessment with the aim to represent various stakeholders’ views on the selected COMBs using a metric of weighting factors. Based on this, a multi-criteria assessment approach featuring a novel ranking factor (EEES) taking into account of energy, economic, environmental and social aspects during retrofit process was adopted. This approach quantifies different stakeholders’ perspectives on the proposed COMBs, which could enable various stakeholders’ involvement in the retrofit decision making process. It was concluded that COMB 05 and 06, which include only 2–3 passive and active EEMs have been ranked and chosen as the most favourable retrofit solutions, with EEES value equalled to 25.6 from various stakeholders’ perspectives. The impacts of changing renewable energy prices and PV generated feed-in tariff rates on the global costs, carbon reductions and primary energy consumptions of the proposed COMBs, which have rarely been analysed in literature, are numerically investigated in this research. Such renewable EEMs which are greatly recommended by the European Commission, are expected to gain further support from national level government renewable incentives. Therefore, it is envisaged that in the long term, Extensive Retrofits incorporating mostly renewable EEMs could become more affordable and cost effective.