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The environmental and economic evaluation of energy renovation in buildings plays a crucial role in achieving sustainability goals and the decarbonization of the built environment. This paper presents a case study of a student house in Athens, Greece, to assess the environmental and economic impacts of energy renovation and seismic reinforcement with a steel exoskeleton. This study utilizes a comprehensive approach that combines life cycle assessment (LCA) and life cycle costing (LCC) methodologies using One Click LCA. The LCA assesses the environmental impacts associated with energy consumption and greenhouse gas emissions, while the LCC evaluates the economic aspects, both analyses being conducted for a lifespan of 25 years from now. The results provide an evaluation of what would happen in terms of greenhouse emissions and costs in two scenarios: with and without interventions. ProGETonE strategy results in an environmental impact with a GWP of 26.78 kgCO2eq/m2y with a reduction of 30% of the pre-renovation state. Economically, the actualized energy use costs for 25 years are 50% less in the post-renovation state, but the high construction costs make the strategy seem inconvenient. In this context, it is important to consider the non-economic benefits of seismic reinforcement, such as enhanced safety and the potential lives saved, which are critical in high seismic zones. These advantages complement the strategy’s environmental and energy use impacts, underscoring the holistic value of integrated seismic and energy retrofitting approaches like ProGETonE. The study underscores the importance of LCA and LCC analyses when evaluating the feasibility of renovation projects and of an evidence-based decision-making process for policymakers, building owners, and stakeholders for energy-efficient retrofitting.

Energy retrofits have, so far, been studied from the perspective of economic benefits that undertaking energy retrofit brings. They have also been of interest in the pursuit of reducing carbon emissions. However, few have studied the perception of health co-benefits of energy retrofits. Therefore, this paper seeks to shed light on how the residents’ perception of their health affects their decision to undertake an energetic retrofit. The focus of this article is to determine how residents perceive their health and their willingness to undertake energy retrofits to improve their health in the municipality of Barcelona. The methods used were in-depth interviews with experts and face-to-face and surveys conducted online. The results were analysed using descriptive, segmental, and unconditional logistic regression. We also analysed if awareness of the health co-benefits of retrofits corresponded with the respondent’s housing conditions, socio-demographics, and willingness to energy retrofit their homes. A total of 127 participants were included, of which 6.3% listed health co-benefit improvements as an influencing factor in undertaking an energy retrofit. The survey findings show that the less educated households are less aware of the health co-benefits of energy retrofits. These findings reveal the need to re-evaluate the current energy and housing policies.

Buildings are responsible for significant energy consumption and carbon emissions. Green buildings, which incorporate advanced building technologies, offer a solution to reducing energy use. However, high costs associated with green building development present a barrier to widespread adoption. Retrofit projects, involving remodeling, renovation, and redevelopment of existing buildings, offer a viable solution. While prior studies have examined the cost analysis of green and non-green buildings, there is a lack of evidence comparing new and retrofit projects. This study aims to address this gap by providing empirical evidence for the cost decomposition and benefits of new and retrofit projects. Data on energy use, building technology, and costs from 235 certified green homes in the United States were collected, and cost benefits were evaluated. Results show that retrofit projects cost, on average, $1270.5/m2 ($118.0/ft2), which is 30% less than new projects. Land acquisition and development account for 35% of retrofit costs, six times greater than new projects. Excluding land costs, retrofit projects cost, on average, $733.88/m2 ($68.2/ft2), 49% less than new projects. Retrofit projects use similar building technologies as new projects and produce larger energy savings. The cost-benefit values generated by retrofit projects are 86% greater than new projects when considering land costs and 142% greater without considering land costs. These findings contribute to cost management for complex building projects and energy policy for sustainable development. Retrofitting offers great potential to promote the green building movement and suggests effective subsidy programs as a public policy implication.

As one of the biggest energy consumers, buildings are the focus of the energy conservation market, and the building envelope, which has the highest impact on heating and cooling loads, is one of the main targets in retrofit projects. Several materials, systems, methods, and simulation tools are used in these projects, and it is critical to understand the impact of these methods in different locations, their frequency of use, and the effectiveness of market-ready new solutions. In that context, it is necessary to review the energy conservation measures (ECMs) that are suitable for residential building envelope retrofitting, and that are commercially available or under research and development. This paper provides an overview of these ECMs. A literature review was conducted on different building envelope ECMs, including traditional and innovative energy retrofit methods, such as aerogel and phase change materials on opaque and transparent components of existing buildings. Results show that the most effective retrofit projects include bundles of ECMs, and the traditional ECMs can be as effective as more innovative solutions in terms of energy saving. Moreover, computer energy models were created for a typical residential building in the US for cold and warm climate zones to determine the impact of different retrofit approaches based on a sensitivity analysis. Results show that envelope ECMs have higher energy saving potentials in cold climate zones, of up to around 30%, and reducing the air infiltration has the highest impact in both cold and warm climate zones in a typical small residential building.

Energy retrofitting of existing residential buildings has a great potential to achieve a sustainable future. One important way to reach this potential is to understand homeowners’ retrofit behaviors due to their crucial roles in retrofit adoption and retrofit effects. Despite many attempts, researchers and governments still know less about the holistic profile of homeowners’ retrofit behaviors, which brought little success in trigging renovation activities and achieving expected retrofit effects. This study tries to fill this research gap by a comprehensive review of the body of existing research. A keyword-based scientometric analysis was performed based on a set of 152 journal articles. By further refining keywords, main research domains pertaining to investment-decision-energy behaviors, policy instruments, retrofit types, construction & services, and methods & methodologies were mapped to show relevant research knowledge and research topics. Based on these research results, a further integrated framework was developed, which explains homeowners’ retrofit behaviors in a systematic way of cross-disciplinary knowledge interactions. Furthermore, implications for retrofit policies in existing buildings were provided. This study is useful for facilitating future research to deepen homeowners’ retrofit behaviors, and also provides valuable references for policy makers to successfully promote home energy retrofit.

Energy retrofitting of buildings shows great potential in reducing CO2 emissions. However, most retrofitting studies only focus on a single building type. This paper shows the relative potential in six Finnish building types, to identify possible focus areas for future retrofits in Finland. Data from previous optimization studies was used to provide optimal cases for comparison. Energy demand of the buildings was generated through dynamic simulation with the IDA-ICE software. The cases were compared according to emissions reduction, investment and life cycle cost. It was found that, in all buildings, it was possible to reduce emissions cost-neutrally by 20% to 70% in buildings with district heating and by 70% to 95% using heat pumps. Single-family homes with oil or wood boilers switching to heat pumps had the greatest emission reduction potential. More stringent requirements for energy efficiency could be mandated during building renovation.

The majority of Italian schools (70%) were built in the absence of any legislation related to energy efficiency, and therefore have very low energy performance due to aging or poor quality of construction. An energy retrofit of this building stock is needed to meet the current European goals on greenhouse gas emission reduction. The retrofit is also needed in order to guarantee adequate comfort levels in indoor spaces and good conditions for learning and educational activities, that are often not reached in poor quality constructions. This work presents the results of an interdisciplinary study related to the energy requalification of a school located in Ostia, near Rome in Italy, built in the 1960s with a steel structure and Eternit infill. The scope of the analysis is to verify the economic and environmental effectiveness of four proposed retrofit interventions concerning the replacement of fixtures and the installation of an insulating coat. The current thermal transmittance of the walls was evaluated through thermofluximetric measurements conducted in situ; dynamic simulations were performed to determine the current energy performance and the energy performances following the four proposed retrofit scenarios. Energy and carbon payback times were evaluated (by means of the life cycle analysis (LCA) approach) and the economic value was determined for each of the four proposed retrofits, using a probabilistic approach. The results show that the replacement of windows is the most convenient intervention from all points of view. The study provides evidence that an assessment of schools’ energy retrofits should include both economic and life cycle aspects.

New Zealand state housing includes a significant portion of problematic buildings constructed after the public housing scheme launched in 1936. Most of these houses are still uninsulated, thus, cold, draughty, mouldy, and progressively decaying; however, as they are fundamental elements of the country’s culture, society, and environment, and are built with good quality materials and sound construction, they are suitable candidates for effective energy upgrades. This paper presents findings of a study on problems and opportunities of retrofitting the state houses built between 1940 and 1960 in the Auckland region. It advocates strategic national policies and initiatives for retrofitting, based on more challenging performance thresholds. The research defines and virtually implements an incremental intervention strategy including different retrofit packages for a typical 1950s stand-alone house. Indoor and outdoor environmental parameters were monitored over a year, and data used to establish a base case for thermal simulation. The upgrade packages were then modelled to assess their impact on the house’s thermal performance, comparing heating requirements and comfort of various insulation and ventilation options. The paper reports on effective ways of preserving the integrity of such a house, while improving its thermal performance to the EnerPHit standard, and discusses the benefits of introducing this holistic approach into New Zealand retrofit practice.

This study examines the need in mild maritime climates, such as the southern areas of the UK, for mechanical ventilation with heat recovery (MVHR) as required by the German Passivhaus standard. It considers the comfort, air quality and energy impacts of MVHR versus natural ventilation and reviews the post-occupancy monitoring data of two flats in Cardiff designed to Passivhaus standards, one of which had been operated as a naturally ventilated building rather than with MVHR. The energy consumption of this free-running flat was significantly lower (36 kWh primary energy/m²a) than the Passivhaus Planning Package modeling had predicted (93 kWh primary energy/m²a) with no adverse effects on occupant comfort, air quality or excessive humidity, and advantages of lower capital cost and maintenance. The paper concludes that in climates with mild winters and cool summers the use of MVHR could be omitted without compromising comfort levels and achieving at least equivalent energy savings resulting from adopting the Passivhaus model and at a lower capital cost. This suggests the potential for a naturally ventilated, ultra-low energy model with lower capital investment requirements and lower disruption when applied to retrofit that would facilitate its mainstream adoption.