Novel Methodology toward Nearly Zero Energy Building (NZEB) Renovation: Cost-Effective Balance Approach as a Pre-Step to Cost-Optimal Life Cycle Cost Assessment

Abstract

Reaching environmental targets set by the European Union (EU) requires a constant renovation of the existing building stock to nearly Zero Energy Buildings (NZEB) in a cost-optimal manner. Studies show that the renovation rate of the existing building stock is more than two times less than what is necessary to reach the targets. Furthermore, the majority of performed renovations across the EU reach just a small amount of energy savings, whereas NZEB renovations are rarely achieved. This paper proposes a methodology for the evaluation of renovation measures, aiming to provide decision support related to the selection of what to renovate and to what extent. The proposed method is rooted in the well-established cost-optimal methodology, yet it suggests a pre-step to package evaluation. This is done by means of a simplified cost-effective parameter (CEP), linking cost, lifetime, and energy savings. The methodology is demonstrated using a case study building in Denmark. The results show that the CEP provides good grounds for the compilation of single actions to packages. Further developments could focus on the sensitivity of the model inputs and integration of additional evaluation parameters to cost, such as environmental, architectural, comfort, risk, etc.

Economic and Energy Performance of Heating and Ventilation Systems in Deep Retrofitted Norwegian Detached Houses

“…Most LCC analyses do not consider uncertainty regarding investment costs, e.g., [11][12][13][14][15][16]. In this study, however, uncertainty on costs was considered by collecting several prices from the current Norwegian market.…”

“…A number of studies have investigated life-cycle costs (LCC) and energy performance in renovation, and many found ambitious measures (e.g., deep-energy renovation) costefficient [11][12][13][14][15][16]. However, few of them addressed detached houses in cold climates, and many used a generic approach with simplified cases and models.…”

Method combining expert and analytical approaches towards economical energy renovation roadmaps and improved indoor comfort

“…This paper proposes a simple, cost-effective method for evaluating renovation measures based on an indicator that links implementation cost, primary energy savings, and lifespan. This approach is preliminary to more detailed cost-optimal life cycle cost analysis that requires more assumptions [5,6].…”

Renovating Building Groups in the Mediterranean Climate: Cost-Effectiveness of Renewable-Based Heating Alternatives in the Italian Context

“…Overall, the integration of RES covering a high share of domestic energy demands is seen as an essential step towards the mitigation of CO 2 emissions and the achievement of urban decarbonized scenarios. A study on a social housing complex from 1949 in Denmark, whose aim was to accelerate stock renovations towards NZEB standards, presents a decision-making methodology supporting the selection of retrofit interventions in buildings [22], based on a previously defined cost-effectiveness parameter (CEP) that couples primary energy savings, renovation costs, and a lifetime of each renovation measure. This study was replicated in Switzerland [23].…”