Energy Efficiency Retrofit Research Articles

Energy poverty alleviation – a step for sustainable energy transition

The paper investigates the issue of fuel poverty and its presence in the Bulgarian context. The focus of the analysis is on the potential for alleviation and – in the long term – elimination of energy poverty through the implementation of measures for energy-efficient retrofit of residential multi-story apartment housing. An effective strategy tackling this topic at the local scale is a key prerequisite for the achievement of the UN Sustainable Development Goals (SDGs) with particular relevance for SDG 7 Affordable and Clean Energy and SDG 11 Sustainable Cities and Communities. Achieving the optimal ratio of saved energy versus financial resources is the key to renovating housing at scale sustainably and efficiently. Energy poverty as a phenomenon is linked to the combined effect of three main factors - low household income, high energy costs and low energy efficiency of housing. There is a broad scientific consensus that this phenomenon has a serious negative impact on the quality of life and citizens’ health and wellbeing. Furthermore, energy poverty contributes to a huge waste of energy and also affects the physical dimension of the sustainable development of the built environment. Therefore, energy poverty exacerbates deficits and discrepancies for territorial economies and communities. Eliminating the problem of “fuel poverty” is often considered to be impossible without the support of the affected households through subsidies. Subsidies invested in energy-efficient housing reconstruction result in immediate savings in housing heating costs, which in turn leads to a tangible reduction in the “fuel poverty” experienced by residents of reconstructed housing. Energy-efficient housing reconstruction (retrofit) is the fastest and most efficient (in terms of public resources) way to combat energy poverty. The financial resources required to enable these activities could also be obtained or complemented through financial engineering schemes with third-party involvement.

To build or not to build, that is the uncertainty: Fuzzy synthetic evaluation of risks for sustainable housing in developing economies

Sustainable housing development is essential for achieving the United Nation's Sustainable Development Goals. However, amid increasing housing deficits, investing in sustainable housing is widely perceived as a risky venture among policymakers and potential developers. This study explores the risk factors that hinder sustainable housing in developing economies using Ghana as a case study. Through a comprehensive literature review, a list of 30 risk factors was established and categorized into five thematic groups. These factors and groups were used to conduct a questionnaire survey among professionals in the Ghanaian housing market to assess progress on achieving sustainable development goals in housing and the risk factors that affect these. Fuzzy synthetic evaluation (FSE) analysis conducted on risk factors revealed that ‘financing-related’ is the most critical risk category followed by ‘procurement-related’, ‘design and construction’, ‘operation and maintenance’ and ‘political-related’ risk factors. By prioritizing the risk categories, the findings apprise policymakers and practitioners of the risk factors that require more attention to achieve sustainable housing development. Additionally, the study stipulates measures for mitigating critical risks and for promoting efficient eminent domain on land, energy efficient retrofitting, transparent procurement, effective contractual strategies and efficient co-production and co-designing for sustainable housing development.

Energy efficiency in the private rental sector in Victoria, Australia: When and why do small-scale private landlords retrofit?

Energy efficiency in private rental properties is lower than that of owner-occupied homes. As landlords are the primary decision-makers for improving rental properties, understanding their energy efficiency behaviour is critical to improving the uptake of energy efficiency retrofits in the private rental sector. However, little is known about how landlords make decisions about energy efficiency retrofits. The study aims to understand when and why landlords decide to retrofit and identify policy implications, using the private rental sector in Victoria as a case study. The results show that proactive retrofitting by landlords is rare and that the retrofits undertaken were generally low-cost, incremental energy efficiency improvements. Most retrofit activity was prompted by government subsidies, tenant requests, or appliance breakdown. Despite its significance for energy efficiency, retrofitting behaviour was not related to environmental values. Instead, landlords considered financial implications and tenants' needs. However, landlords who used property managers had little understanding of tenants' needs. Policymakers can use this understanding of landlords' behaviour by creating new retrofit prompts and highlighting the impacts of energy inefficiency on tenants' wellbeing. Transitioning the private rental sector to low-energy housing requires integrated policy to change the behaviour of landlords, tenants, and property managers.

Sustainable Buildings’ Energy-Efficient Retrofitting: A Study of Large Office Buildings in Beijing

Energy-efficient retrofitting has emerged as a primary strategy for reducing the energy consumption of buildings. Buildings in China account for about 40% of total national energy consumption. Large office buildings account for the most. Less than 5% of the building area of existing office buildings is energy efficient. Energy-efficient retrofitting for sustainable buildings is a complicated system that involves various sustainable dimensions and operational technical schemes. Making multi-criteria decisions becomes a challenging problem for stakeholders. Based on the theory of sustainability, this paper establishes a sustainable analysis framework to guide stakeholders to select an optimal technical combination of energy-efficient retrofit measures for large office buildings. Based on empirical data collected in Beijing, a number of energy efficiency measures are selected, tailored and applied to a virtual model of a typical large office building. Technical features and the energy performance are simulated accordingly. The energy consumption, energy-saving ratio and lifecycle costs are derived to identify the optimal configuration. The outcome of this research offers a feasible technical plan for stakeholders relating to technical design and design making. The study finds that an LED lighting system and frequency conversion device for the cooling water chiller cannot only sufficiently reduce the building’s energy consumption but also perform economically. Different thermal insulation materials for reconstructing the building envelope have no obvious effect on the thermal performance in comprehensive simulations of technology combinations. The sustainable analysis framework offers theoretical and practical support and can be used as a reference for the other types of buildings in future research.

Optimization and BIM-based lifecycle assessment integration for energy efficiency retrofit of buildings

A retrofit plan for improving the energy efficiency of an existing building can contribute to a sustainable built environment. This study presents a novel framework for integrating mathematical optimization, 6D-Building Information Modeling (BIM), and Life Cycle Assessment to enhance existing buildings' energy efficiency through applying energy retrofit measures. This framework aims to (1) integrate life cycle cost, and environmental impacts analysis (2) identify energy-efficient alternatives for buildings' energy retrofit (3) make the decision-making process straightforward for decision-makers and investors (4) discover the primary energy efficiency agents that impose the most energy waste on existing buildings. This study contributes to the body of knowledge by applying effective retrofit measures and alternative material choice and empowers decision-making by analyzing life cycle cost and environmental impacts of building envelopes by combining mathematical optimization, BIM, and LCA. The BIM energy model compares the cooling and heating loads of the building's components before and after applying retrofitting measures. The results show that inefficient buildings' envelopes and evaporative coolers play a significant role in energy consumption. A developed mathematical optimization model estimates the economic benefits of energy efficiency upgrades to minimize the total lifecycle cost of a building during its lifetime. Moreover, it provides an optimum energy retrofitting scenario that leads to reductions of 24%–58.2% in energy consumption. In conclusion, the Life Cycle Assessment Comparison between the building before and after retrofitted measures demonstrates that over 45% of global warming impacts could be reduced in the well-established building.

Retrofitting Existing Buildings to Improve Energy Performance

Energy-efficient retrofits embrace enhancement of the building envelope through climate control strategies, employment of building-integrated renewable energy technologies, and insulation for a sustainable city. Building envelope improvements with insulation is a common approach, yet decision-making plays an important role in determining the most appropriate envelope retrofit strategy. In this paper, the main objective is to evaluate different retrofit strategies (RS) through a calibrated simulation approach. Based on an energy performance audit and monitoring, an existing building is evaluated on performance levels and improvement potentials with basic energy conservation measures. The considered building is experimentally monitored for a full year, and monitoring data are used in calibrating the simulation model. The validation of the base model is done by comparing the simulation analysis with the experimental investigation, and good agreement is found. Three different retrofit strategies based on Intervention of minor (RS1), Moderate (RS2), and Major (RS3) are analyzed and juxtaposed with the base model to identify the optimal strategy of minimizing energy consumption. The result shows that total energy intensity in terms of the percentage reduction index is about 16.7% for RS1, 19.87 for RS2, and 24.12% for RS3. Hence, RS3 is considered the optimal retrofit strategy and is further simulated for a reduction in carbon dioxide (CO2) emissions and payback investigation. It was found that the annual reduction in CO2 emissions of the building was 18.56%, and the payback period for the investment was 10.6 years.

An Assessment of the Key Performance Indicators (KPIs) of Energy Efficient Retrofits to Existing Residential Buildings

Quantifying the wider benefits of energy efficient building retrofits is crucial to incentivise householder retrofit investments. This research recognises the value of key performance indicators (KPIs) for assessing and demonstrating retrofitting benefits and provides an assessment of KPIs for evaluating retrofits. An integrated framework for evaluating retrofits using a set of economic, social, and environmental KPIs is proposed. This KPI framework is then applied in a pre- and post-retrofit assessment of five case study dwellings located in Ireland, revealing its usefulness in demonstrating the wider benefits of retrofitting to householders, with a view to driving retrofit investment. Three of these case study dwellings had state-of-the-art retrofit technologies installed as part of the works, including heat pumps and solar PV systems. In addition to demonstrating the wider benefits of retrofitting, the framework allowed for the identification of potential causes for differences in performance of these technologies across households, as well as patterns of underperformance. Such insights are useful for the future design of these technologies and retrofit packages, as well as policy measures, which support householders in the adoption and use of these measures. The results demonstrate that householders experience various benefits from retrofitting. Showcasing the different benefits that householders receive from retrofitting, and their satisfaction with the retrofit works, can serve to de-risk retrofit investments, and inspire others to seek similar benefits through retrofitting. Applying the developed framework to a larger, comparable sample size, can distinguish the retrofit packages, which perform best across the KPIs and various household profiles. Furthermore, the application of the developed framework can serve as an evidence base for retrofit designers, contractors, and policy makers in the design of retrofit packages and policy measures that will maximise the benefit for householders.

Building glass retrofitting strategies in hot and dry climates: Cost savings on cooling, diurnal lighting, color rendering, and payback timeframes

Building glazing is a weak thermal envelope that admits too much solar heat, resulting in increased air conditioning expenditures. An optimal glazing system must be chosen to promote the thermal and visual comfort of building interiors. The current study examines how different glass retrofits affect the air-conditioning cost savings of an office building in a hot and dry region of India. To assess the thermal performance of the building, the apertures of the office building were retrofitted with brick glass, stained, tinted, reflective, laminated, polymer dispersed liquid crystal film glazing, and double-glazed window systems. The spectral characteristics of the studied retrofit glazing systems were measured experimentally, and a mathematical model was developed to estimate the heat gain, cooling cost demand, and energy savings for air-conditioning. The polymer dispersed liquid crystal film glazing retrofit provided the highest average air-conditioning cost savings (5.11 $/m2), while the air-filled double-glazing configuration showed the lowest (0.30 $/m2), relative to the original glazing installation among the other retrofits tested. The examined retrofit glazing systems have a colour rendering index of more than 80, indicating appropriate lighting quality. The findings of this study are critical in determining the most energy-efficient retrofit glazing solutions for energy-conscious building design.

Financial model adaptation for building energy efficiency retrofits in Turkey

Financial model adaptation for building energy efficiency retrofits in Turkey

Machine Learning Techniques Focusing on the Energy Performance of Buildings: A Dimensions and Methods Analysis

The problem of energy consumption and the importance of improving existing buildings’ energy performance are notorious. This work aims to contribute to this improvement by identifying the latest and most appropriate machine learning or statistical techniques, which analyze this problem by looking at large quantities of building energy performance certification data and other data sources. PRISMA, a well-established systematic literature review and meta-analysis method, was used to detect specific factors that influence the energy performance of buildings, resulting in an analysis of 35 papers published between 2016 and April 2021, creating a baseline for further inquiry. Through this systematic literature review and bibliometric analysis, machine learning and statistical approaches primarily based on building energy certification data were identified and analyzed in two groups: (1) automatic evaluation of buildings’ energy performance and, (2) prediction of energy-efficient retrofit measures. The main contribution of our study is a conceptual and theoretical framework applicable in the analysis of the energy performance of buildings with intelligent computational methods. With our framework, the reader can understand which approaches are most used and more appropriate for analyzing the energy performance of different types of buildings, discussing the dimensions that are better used in such approaches.

Cost-related analysis of implementing energy-efficient retrofit measures in the residential building sector of a middle-income country – A case study of Bosnia and Herzegovina

This study presents an in-depth analysis of the cost structure when planning EE retrofit measures in the residential sector in Bosnia and Herzegovina. The analysis showed that implementing EE retrofit measures would result in substantial energy savings in single-family houses, however, the specific cost of implementing EE retrofit measures per resident for single-family houses is on average 2.8 times higher than for the other three categories; multi-family houses, apartment buildings, and high-rise buildings. When considering the ratio between the investment costs and GDP per capita showed that the citizens in Bosnia and Herzegovina have four times lower ability to finance EE retrofit measures compared to three other representatives EU members and therefore government subsidy schemes may be inevitable for successfully implementing EE retrofit strategies. The general conclusion based on the cost-effective analysis is that EE retrofit investments, may not be financially viable in single-family houses, multi-family houses, and apartment buildings even if supported by government subsidies due to the very low prices of energy sources (coal and wood) used in these specific building prototypes. On contrary, high-rise buildings, that are mainly driven by natural gas and light distillate fuel oil, show a great EE retrofit-driven profitability in. Looking at the financial assessment outcomes, the most significant benefits are mainly related to retrofit scenario that accounts for improvement in the external wall insulation, window glazing, and improving the heating station efficiency. Looking at the carbon emission outcomes, the most significant benefits in reducing the relative and averaged CO2 emission are strongly related to replacing the existing partly coal-burned furnaces (80% firewood + 20 % coal) in single-family houses with exclusive firewood fueled heating systems. This measure may have an enormous impact on reducing the CO2 emission from single-family houses (minimum 83.1 %), which cover 93.1 % of the total residential building stock in Bosnia and Herzegovina. This study may benefit low and middle-income governments in their aim to translate potential EE retrofit measures in the residential sector to a nationwide economic energy-saving policy.

Ortho-photogrammetry for prefabricated energy-efficiency retrofits

Panel-based prefabricated retrofits of existing building envelopes are considered a promising strategy for improving energy performance and reducing greenhouse gas emissions. These projects typically require some form of 3D model of the as-is building geometry, in order to construct the panels offsite, and, currently they tend to use laser scanning for this purpose, because of their accuracy requirements. However, laser scanners must be operated from a tripod, and producing drawings from scans is a largely manual process involving unwieldy amounts of data. We propose a line-photogrammetric approach that requires a small number of photographs (typically 8), that we call ‘Ortho-Photogrammetry’. Ortho-Photogrammetry is parametrised by axis-aligned planes and produces rectified geometry suitable for panel construction. It does not require a calibrated camera or targets. We demonstrate that it is sufficiently accurate to support prefabricated retrofits, even when used with photos from a consumer UAV.

Impact of demand response on occupants\u2019 thermal comfort in a leisure center

Many assets that are normally installed during an energy-efficient building retrofit can also be used to provide flexible services to the electricity grid. By turning off or turning down some mechanical systems during peak times, it is possible for a building to reduce its load on the electricity network. A field demand response event was simulated at a leisure center in Ireland to evaluate the suitability of the site to participate in the Irish demand response market, to assess how much flexibility it can provide, how much the indoor conditions changed during the test, and to examine whether these remained within satisfactory limits. A survey was conducted to determine whether the occupants perceived any changes to their thermal comfort. The simulation was achieved by identifying non-critical mechanical equipment and turning them off for 2 h. A processing station for demand response and energy monitoring delivered the demand response signal to the site’s building management system. The results show that this site had a flexibility potential of 45 kW, which is considered too low to participate in the demand response market, as Irish aggregators favor sites that can offer over 250-kW flexibility. However, the indoor thermal conditions remained within reasonable ranges and the occupants did not notice the impact of the demand response event. This shows that theoretically, if smaller sites were allowed to sell their flexibility to the electricity market, such leisure centers could participate in demand response services without impacting occupants’ comfort.

Actual energy savings of more than 1000 renovated buildings in Geneva

This study quantifies the annual energy-related retrofit rate of the Geneva building stock (1.7%), based on data concerning the delivered construction permits over the 2010 – 2018 period. By cross-cutting with final energy demand before and after retrofit, we derive an energy-efficient retrofit rate (0.6% for an improvement of 1 class at least, 0.2% for 2 classes at least). Results are analysed as a function of the construction period, as well as of the energy demand before retrofit.

Financing energy efficiency retrofits in Chilean households: The role of financial instruments, savings and uncertainty in energy transition

High firewood consumption for heating produces high levels of pollution in cities in central and southern Chile, with serious consequences for health and quality of life. Energy efficiency measures (EEMs) have been identified as the best strategy to reduce air pollution and maximize social benefits. However, their adoption has been slow. The objective of this article is to investigate household preferences for financial incentives needed to promote private investments in EEMs in Central-Southern Chilean households and study the role of energy savings and the uncertainty about potential savings in the investment decision, with the aim of finding solutions to increase the adoption of these technologies. We use a choice experiment to explore the trade-off between the investment costs, financial instruments, energy savings, and the uncertainty about achieving the theoretical savings provided by engineering and architectural models. The results show that financial instruments play the most important role in this decision, followed by the savings achieved by the retrofit. Householders prefer to finance their investments with a mix of their personal resources and medium-term credits, trying to avoid long-term commitments. Although uncertainty was found to be a significant variable, it seems to play a small role in the investment decision.

Engaging UK repair–maintain–improve practitioners in improved building performance

PurposeTo improve building performance and meet statutory carbon reduction targets, a radical transformation of existing UK building stock is needed. Much previous research on building performance has focussed on large-scale construction. However, retrofit of existing housing stock – which will contribute the majority of the requisite efficiency improvement – is carried out by practitioners in the repair–maintain–improve (RMI) subsector. These practitioners are the sole traders and micro-firms who constitute two-fifths of employment in the construction sector. The study aims to examine the factors influencing these practitioners in RMI work to understand how better to engage them with improved building performance.Design/methodology/approachA total of 31 semi-structured interviews were conducted with RMI professionals from around the UK and analysed using template analysis.FindingsThe analysis identified capabilities of the practitioners who influence building performance, including knowledge and co-ordination of people and resources; opportunities including state action and customer demand; and motivations including pride in work, customer care and satisfaction, maintaining a viable business and working relationships.Research limitations/implicationsThe participants were a small, mixed group in terms of firm size and specialisation. The qualitative approach adopted provided detailed insights but does not make claims for statistical generalisability or representativeness of the findings. Future work could look to extend the findings with a statistically representative survey.Practical implicationsFor a successful transition to high standards of building performance, modelling is not enough. Initiatives are needed to address the multiple factors which determine engagement in energy-efficient retrofit: capacities, opportunities and motivations. The desire of RMI practitioners to meet customer expectations could be used to develop pragmatic building performance evaluation, guided by householder satisfaction criteria.Originality/valueThe study examined the attitudes and experiences of an under-researched sector who are essential to the delivery of improved building performance. This study makes a novel contribution by applying an established psychological model of behaviour change, the capability, opportunity, motivation – behaviour model, for the first time in this domain.

An examination of energy efficiency retrofit scheme applications by low-income households in Ireland

This paper studies the determinants of why low-income households in Ireland abandon energy efficiency retrofit applications using administrative data from a targeted energy efficiency grant. By applying for the scheme, the applicants overcome any financial barriers for undertaking retrofits and demonstrate their willingness to improve the energy efficiency of their dwellings. Hence this study contributes to the scarce literature on non-financial barriers preventing low-income households from undertaking energy efficiency retrofits. Contrary to previous findings, we find that the higher the number of retrofits to be implemented, the lower the probability of households abandoning their applications. We also find that planning to undertake retrofits such as ventilation, which can significantly improve the health and safety standards of the dwelling, is associated with a higher probability of abandonment. Both findings indicate the presence of key behavioural and informational barriers which prevent low-income households from fully comprehending the purpose or benefits of proposed energy efficient retrofits. Our findings also suggest that higher grant expenditure on dwellings with poor pre-works energy efficiency rating and on retrofits such as attic insulation and heating system upgrades may have the highest energy efficiency improvements per unit of expenditure. Within the constraints of limited budgets for retrofit grant supports, this research can inform the redesign of grant schemes to achieve the greatest aggregate improvements in residential building energy efficiency.

Towards an integrated moisture-safe retrofit process for traditional buildings in policy and industry

Improving the energy efficiency of traditional buildings, which represent a large proportion of the building stock in the UK, is necessary to meet national targets on greenhouse gas emissions and alleviate fuel poverty. Traditional dwellings in the UK are defined as hard-to-treat homes because insulating them is not cost-effective or might lead to moisture-related issues. This has led to efforts from policy-makers and organisations towards minimizing moisture risk in the energy-efficient retrofit of traditional buildings. This paper presents an overview of the work done towards a moisture-safe retrofit in the UK in the past ten years, focusing on the Government’s policies and the work and legacy of the late Neil May, one of the pioneers in sustainable traditional buildings in the UK.

Energy Savings Results from Small Commercial Building Retrofits in the US

Small commercial buildings, or those comprising less than 50,000 square feet of floor area, represent 94% of U.S commercial buildings by count and consume approximately 8% of the nation’s primary energy; as such, they represent a largely unexploited opportunity for energy savings. Small commercial buildings also represent a large economic market—the National Institute of Building Sciences (NIBS) estimated the small commercial retrofit market at USD 35.6 billion. Despite the prominence of small commercial buildings and the economic opportunity for energy retrofits, many energy efficiency programs focus on large commercial buildings, and create efficiency solutions that do not meet the needs of the small commercial market. This paper presents an analysis of 34 small commercial case study projects that implemented energy efficiency retrofits. This paper contributes to the existing building retrofit body of knowledge in the following ways: (1) it identifies the decision criteria used by small commercial building stakeholders that decided to complete an energy retrofit; (2) it identifies the most commonly implemented efficiency measures in small commercial buildings, and discusses why this is the case; and (3) it provides empirical evidence about the efficacy of installing single energy efficiency measures (EEMs) compared to packages of EEMs in small commercial buildings by reporting verified energy savings. To the authors’ knowledge, this paper is the first to catalog decision criteria and energy savings for the existing small commercial buildings market, and this research illustrates that small commercial building decision-makers seem most motivated to retrofit their spaces by energy cost savings and operational concerns. Furthermore, small commercial building decision-makers opted to implement single-system retrofits in fifteen (15) of the thirty-four cases studied. Finally, this research documents the improved savings, in the small commercial buildings market, associated with a more integrated package of EEMs compared to a single-system approach, achieving approximately 10% energy savings for a single-system approach and more than 20% energy savings for integrated approaches. These savings translate to CO2 savings of 1,324,000 kgCO2/year to 2,647,000 kgCO2/year, respectively, assuming small commercial buildings are retrofit at a rate of 0.95% of the stock annually.

Economic and regional spillovers of energy efficiency investments in buildings

This paper explores whether the policy of mitigating climate change through energy-efficient retrofitting supports more balanced development or increases regional disparities. The issue is explored through the estimation of the socioeconomic effects of energy-efficient renovation across Croatian regions. The regional input–output model is applied to identify direct, indirect, and induced effects of building retrofit investments on gross value added and employment. In the Croatian case, over three-quarters of the total economic effects of energy-efficient retrofitting is distributed to the more developed region of Continental Croatia. Economic activity in the Adriatic region is strongly dependent on tourism with insufficient local production of the manufacturing products required in energy renovation projects, and a certain proportion of spillover effect of the investment is transferred to Continental Croatia. The positive economic effects induced by retrofit investments are most present in construction, manufacturing, trade, and transport. Results suggest that climatic conditions and regional economic specialisation have an impact on the dispersion of the economic effects of retrofit measures in different regions.