Multifamily energy-efficiency retrofit programs: a Florida case study

Multifamily buildings are an important target for efficiency improvements because of their energy savings potential and housing market share. Yet few multifamily retrofit projects have been completed in hot-humid regions and even fewer studies have measured and verified savings from such projects. Addressing this gap, the purpose of our research is to assess the impacts of energy-efficiency upgrades to multifamily buildings in Orlando, FL. Specifically, we measure the first-year electricity savings from retrofits to 232 units in four apartment complexes. Annual savings per unit averaged 2094 kWh (22 %) and ranged from 1700 kWh (18 %) to 3811 kWh (29 %) across complexes. Monthly savings ranged from 48 kWh (9.4 %) in December to 340 kWh (31 %) in August. From these core findings, we estimate that tenants in treatment units saved an average of $272 on their electric bills. We also find evidence to support a strategy of targeting upgrades to improve overall savings and program cost-effectiveness. Results are being used to guide development of a utility demand-side management program for multifamily property owners. Progress in this market requires additional pilot projects, access to utility data, reliable measurement and verification of savings, and innovative financing structures.     

Disaggregating the causes of falling consumption of domestic heating energy in Germany

Consumption of domestic heating energy (space and water heating combined) in Germany has been falling in recent years. Official figures indicate it fell by 17 % in 2000–2011, from 669 to 564 TWh (temperature adjusted), while the population reduced by 2 % and the number of occupied dwellings increased by 3.4 %. German policy has strongly promoted deep thermal retrofits through regulation, information campaigns and subsidised loans. An important question is what portion of the reductions are due to progressive energy efficiency upgrade policy and what are due to other, non-technical factors such as demographic and behaviour change. We use national statistics and existing empirical studies to disaggregate the contribution of energy-efficiency improvements and nontechnical factors to the reduction in consumption. Our analysis suggests that around 20 % of the reductions are likely to be due to thermal retrofits of existing dwellings (insulation and new windows), 31 % due to boiler or heating system replacements, 1 % due to replacement of old dwellings with new, energy-efficient buildings, while some 45–50 % of the savings cannot be explained by these technical improvements. Most of these reductions appear to have occurred in non-upgraded, non-new dwellings. Although we do not know what caused these reductions, the finding is robust to very wide inaccuracies in figures for savings through technical improvements in buildings’ energy efficiency. More research is needed to explore the extent to which this implies increasing fuel poverty, increasing skills and motivation among non-poor households to heat more economically, or the effects of demographic and lifestyle changes. Highlights ? German home heating energy consumption fell by 105 TWh in 2000–2011 ? Approximately 31 % of this was due to boiler/heating system upgrades ? Approximately 20 % was due to window replacement and thermal envelope upgrade ? Less than 1 % was due to replacement of old with new stock ? Over 45 % cannot be explained by technical upgrade factors ? This could imply rising fuel poverty or more skilful heating behaviour     

Energy performance analysis of a dormitory building based on different orientations and seasonal variations of leaf area index

The aim of this research is to investigate the effectiveness of vertical vegetation in terms of energy savings for a residential facility situated at KAIST campus. The research has been established through analyzing different building orientations to find out the most suitable combination of vegetation and orientation for reduced heating and cooling energy consumption. A simulation model has been developed where leaf area index, one of the contributing plant physiological parameters for improving building thermal performance, has been incorporated as per seasonal variations. This allowed observing thermal performance patterns of green wall throughout the year. Approximately 60 % savings in heating energy and 31 % increase in overall energy efficiency were achieved with the non-insulated studied building case, and the results showed extreme weather conditions lead to greater energy savings in winter. In cooling season, plant layers were found to be less effective in terms of facade thermal performance especially during relatively higher temperature period, with an average of 17 % cooling energy savings. The North-oriented green wall was observed to be the most effective in increasing heating energy efficiency, while the East-oriented wall was observed to be greatest in cooling energy savings. A higher LAI value proved to be beneficial in improving both heating and cooling energy performance for the studied building.     

Prioritizing investment in residential energy efficiency and renewable energy—A case study for the U.S. Midwest

Residential building energy use is an important contributor to greenhouse gas emissions and in the United States represents about 20% of total energy consumption. A number of previous macro-scale studies of residential energy consumption and energy-efficiency improvements are mainly concerned with national or international aggregate potential savings. In this paper we look into the details of how a collection of specific homes in one region might reduce energy consumption and carbon emissions, with particular attention given to some practical limits to what can be achieved by upgrading the existing residential building stock. Using a simple model of residential, single-family home construction characteristics, estimates are made for the efficacy of (i) changes to behavioral patterns that do not involve building shell modifications; (ii) straightforward air-infiltration mitigation measures, and (iii) insulation measures. We derive estimates of net lifetime savings resulting from these measures, in terms of energy, carbon emissions and dollars. This study points out explicitly the importance of local and regional patterns in decision-making about what fraction of necessary regional or national emissions reduction might be accomplished through energy-efficiency measures and how much might need to concentrate more heavily on renewable or other carbon-free sources of energy.     

Efficiency improvement opportunities for televisions in India: implications for market transformation programs

Televisions (TVs) account for a significant portion of residential appliance electricity consumption in India, and TV shipments in India are expected to continue to increase. We assess the market trends in the energy efficiency of TVs that are likely to occur without any additional policy intervention and estimate that TV efficiency will likely improve with saving potential of 6 terawatt-hours (TWh) per year in 2020, compared to today’s technology. We discuss various energy-efficiency improvement options and evaluate the cost-effectiveness of three of them, at least one of which improves efficiency by at least 20 % cost-effectively beyond these ongoing market trends. We provide insights for policies and programs that can be used to accelerate the adoption of efficient technologies to capture the cost-effective energy savings potential from TVs which we estimate to be 3.4 TWh per year in 2020.     

Refurbishment of public housing villas in the United Arab Emirates (UAE): energy and economic impact

This study aims at assessing the technical and economic benefits of refurbishing existing public housing villas in the UAE. Four representative federal public housing villas built between 1980s and 2010s were modeled and analyzed. The Integrated Environmental Solutions-Virtual Environment (IES-VE) energy modeling software was used to estimate the energy consumption and savings due to different refurbishment configurations applied to the villas. The refurbishment technical configurations were based on the UAE’s Estidama green buildings sustainability assessment system. The refurbishment configurations include upgrading three elements: the wall and roof insulation as well as replacing the glazing. The annual electricity savings results indicated that the most cost-efficient refurbishment strategy is upgrading of wall insulation (savings up to 20.8 %) followed by upgrading the roof’s insulation (savings up to 11.6 %) and lastly replacing the glazing (savings up to 3.2 %). When all three elements were refurbished simultaneously, savings up to 36.7 % were achieved (villa model 670). The savings translated to CO₂ emission reduction of 22.6 t/year. The simple and discounted payback periods for the different configurations tested ranged between 8 and 28 and 10 and 50 years, respectively.     

Energy savings potential from improved building controls for the US commercial building sector

The US Department of Energy (DOE) sponsored a study to determine the national savings achievable in the commercial buildings through widespread deployment of controls, elimination of faults, and use of better sensing. The study estimated savings from 34 measures in 9 building types and across 16 climates. These buildings are responsible for almost 57% of the US commercial building sector energy consumption. In addition to the individual measures, three packages of measures were created to estimate savings: (1) efficient building, (2) typical building, and (3) inefficient building. The results showed significant potential for energy savings across all building types and climates. The total site potential savings by building type aggregated across all climates for each measure varied between 0 and 16%. The total site potential savings aggregated across all building types and climates for each measure varied between 0 and 11%. The national potential site energy savings across all building types studied is 29%. Across all building types, the savings represent approximately 1393 PJ (1.32 quads) of site energy savings or 2912 PJ (2.76 quads) of primary (or source) energy savings. Extrapolating the results for other building types not analyzed as part of this study, the primary energy savings could be in the range of 4220 to 5275 PJ. For comparison, the total US primary energy consumption across all sectors of energy use was 102,762 PJ (97.4 quads) in 2015. This makes commercial building control improvements strategically important to sustained reductions in national energy consumption. To realize most of this potential savings, many gaps can be addressed through research development and deployment (RD&D), as recommended in this paper.     

Implementing Home Energy Rating Systems

We evaluate the implementation of home energy rating and labelling programs (HERS) that are being conducted around the country. We examine the nature of different implementation problems and the kinds of strategies that have been used to deal with them to ensure the effective penetration of HERS to all HERS users. Based on our evaluation of 34 home energy rating and labelling programs, HERS that were actively marketed, had a comprehensive appreciation of the market, were adaptive to the needs of particular users, and included user participation in the operation and revision of the program were more successful in terms of penetration rates and in improving the energy efficiency of the older housing stock. Where successful, HERS have penetrated an estimated 40% of the new construction market and 20% of existing construction, and energy savings have ranged from 10 to 50%.     

A study of energy performance and audit of commercial mall in hot-summer/warm-winter climate zone in China

The building energy performance improvement of large-scale public buildings is very important to release China’s energy shortage pressure. The aim of the study is to find out the building energy saving potentials of large-scale public and commercial buildings by energy audit. In this paper, the energy consumption, energy performance, and audit were carried out for a typical commercial mall, the so-called largest mall in Asia, located in a hot-summer and warm-winter climate zone. The total annual energy consumption reaches 210.01 kWh/m², of which lighting energy consumption accounts for 30.03 kWh/m² and the lift and elevator energy consumption accounts for 40.46 kWh/m². It is by far higher than that of the average building energy consumption in the same category. However, the annual heating, ventilation, and air-conditioning (HVAC) energy consumption is only 87.19 kWh/m² even though they run 24/7. It proves that the energy performance of the HVAC system is good. Therefore, the building energy savings potential mainly relies on reducing the excessive usage of lighting, lifts, and elevators.     

Energy-efficiency supervision systems for energy management in large public buildings: Necessary choice for China

Buildings are important contributors to total energy consumption accounting for around 30% of all energy consumed in China. Of this, around two-fifths are consumed within urban homes, one-fifth within public buildings, and two-fifths within rural area. Government office buildings and large-scale public buildings are the dominant energy consumers in cities but their consumption can be largely cut back through improving efficiency. At present, energy management in the large public sector is a particular priority in China. Firstly, this paper discusses how the large public building is defined, and then energy performance in large public buildings is studied. The paper also describes barriers to improving energy efficiency of large public buildings in China and examines the energy-efficiency policies and programs adopted in United States and European Union. The energy-efficiency supervision (EES) systems developed to improve operation and maintenance practices and promote energy efficiency in large public sector are described. The benefits of the EES systems are finally summarized.     

Engaging residents in affordable housing—resident engagement pilot at Denver Housing Authority Westridge apartments

Denver Housing Authority (DHA) has invested considerably into designing, building, and maintaining a resource efficient portfolio and this effort is becoming increasingly comprehensive as they continuously refine and build upon their approach. One of the more recent strategies was to incorporate resident engagement efforts focused on energy and water efficiency into their programming as a way not only to maximize realized energy savings from these investments but to also to engage with building occupants around sustainability initiatives and develop a holistic approach to reducing their resource consumption. In 2014, DHA hired Energy Outreach Colorado and Group14 Engineering (the Team) to develop and implement a voluntary program designed to encourage positive environmental and social actions around energy and water use. The Team developed a comprehensive resident engagement and outreach program involving on-site staff, resident leaders, and residents. The program plan identified both low/no-cost solutions and more extensive outreach efforts targeted at the DHA Westridge community. Upon completion of the pilot, the program achieved 24,864 kWh (4.5%) savings in electricity consumption. Valued at the 2014 effective blended rate for Westridge, this equals $3493 dollars in annual savings and a program payback of 11 years. The project’s participation goal was exceeded, with 60% of the neighborhood households participating in the program. The team concluded that achieving savings through resident engagement is possible but also the level of effort put forth in the project is important to consider.     

Energy savings versus costs of implementation for demand side management strategies within an energy-efficient tropical residence

As renewable energy sources and net-zero energy homes become increasingly pervasive within the residential building industry, further reductions in consumption patterns will occur through demand side management (DSM). DSM can include measures such as energy-efficient system design, automated control and energy management systems, or policies and monitoring systems intended to alter user behavior. For an energy-efficient modern residence designed within a tropical context, several DSM strategies are considered for reductions in operational-phase energy consumption: a lightweight, thermally high-performing building envelope, installation of light dimmers to enhance user control of lighting, and comparison of a solar hot water system versus a point-of-use electric water heater to produce hot water for bathing demands. The energy-consumption savings associated with the three DSM strategies are simulated and normalized to an energy savings per cost of implementation basis in kWh per 1000 Thai Baht (THB) for comparison. The results show that financial investments in low-energy hot water heaters (i.e., solar water heating systems) result in relatively higher energy savings per unit financial investment than the other two strategies. Conversely, the installation of a lightweight, well-insulated envelope is highly expensive relative to its associated energy savings over a 25-year time frame. The savings associated with the insulated envelope, light dimmers, and hot water production strategies are evaluated at 80, 609 and 657 kWh/1000 THB investment, respectively.     

Assessment of China's energy-saving and emission-reduction accomplishments and opportunities during the 11th Five Year Plan

From 1980 to 2002, China experienced a 5% average annual reduction in energy consumption per unit of gross domestic product (GDP). With a dramatic reversal of this historic relationship, energy intensity increased 5% per year during 2002–2005. China's 11th Five Year Plan (FYP) set a target of reducing energy intensity by 20% by 2010. This paper assesses selected policies and programs that China has instituted to fulfill the national goal, finding that China made substantial progress and many of the energy-efficiency programs appear to be on track to meet – or in some cases exceed – their energy-saving targets. Most of the Ten Key Projects, the Top-1000 Program, and the Small Plant Closure Program will meet or surpass the 11th FYP savings goals. China's appliance standards and labeling program has become very robust. China has greatly enhanced its enforcement of new building energy standards but energy-efficiency programs for buildings retrofits, as well as the goal of adjusting China's economic structure, are failing. It is important to maintain and strengthen the existing energy-saving policies and programs that are successful while revising programs or adding new policy mechanisms to improve the programs that are not on track to achieve the stated goals.     

Quantification of energy savings from Ireland’s Home Energy Saving scheme: an ex post billing analysis

This paper quantifies the energy savings realised by a sample of participants in the Sustainable Energy Authority of Ireland’s Home Energy Saving (HES) residential retrofit scheme (currently branded as the Better Energy Homes scheme), through an ex post billing analysis. The billing data are used to evaluate: (1) the reduction in gas consumption of the sample between pre- (2008) and post- (2010) scheme participation when compared to the gas consumption of a control group, (2) an estimate of the shortfall when this result is compared to engineering-type ex ante savings estimates and (3) the degree to which these results may apply to the wider population. All dwellings in the study underwent energy efficiency improvements, including insulation upgrades (wall and/or roof), installation of high-efficiency boilers and/or improved heating controls, as part of the HES scheme. Metered gas use data for the 210 households were obtained from meter operators for a number of years preceding dwelling upgrades and for a post-intervention period of 1 year. Dwelling characteristics and some household behavioural data were obtained through a survey of the sample. The gas network operator provided anonymised data on gas usage for 640,000 customers collected over the same period as the HES sample. Dwelling type data provided with the population dataset enabled matching with the HES sample to increase the internal validity of the comparison between the control (matched population data) and the treatment (HES sample). Using a difference-in-difference methodology, the change in demand of the sample was compared with that of the matched population subset of gas-using customers in Ireland over the same time period. The mean reduction in gas demand as a result of energy efficiency upgrades for the HES sample is estimated as 21 % or 3,664?±?603 kWh between 2008 and 2010. An ex ante estimate of average energy savings, based on engineering calculations (u value reductions and improved boiler efficiency and use through heating controls), suggests a technical reduction potential of 5,676 kWh per dwelling. Equating this with the gas reduction in the sample suggests a shortfall of approximately 36?±?8 % between technical potential and measured savings. This shortfall includes the effects of direct and indirect rebound effects, variations in ex ante assumptions and achieved u values and efficiencies for upgraded dwellings. The profile of household characteristics in the HES sample is influenced by the self-selected nature of scheme participants. Self-selection bias and other possible biases in the sample data impact on the validity of the comparison. Data limitations for individual households across explanatory variables in the control and treatment groups precluded corrections for these biases in the sample; however, the profiles of separate comparable data sets were used where possible to quantify the differences in the explanatory variables and how these might impact on the measured energy saving with reference to the relevant effects identified in the literature.     

Taming the energy use of gaming computers

One billion people around the world engage in some form of digital gaming. Gaming is the most energy-intensive use of personal computers, and the high-performance “racecar” systems built expressly for gaming are the fastest growing type of gaming platform. Large performance-normalized variations in nameplate power ratings for gaming computer components available on today’s market indicate significant potential for energy savings: central processing units vary by 4.3-fold, graphics processing units 5.8-fold, power supply units 1.3-fold, motherboards 5.0-fold, and random access memory (RAM) 139.2-fold. Measured performance of displays varies by 11.5-fold. However, underlying the importance of empirical data, we find that measured peak power requirements are considerably lower than nameplate for most components tested, and by about 50 % for complete systems. Based on actual measurements of five gaming PCs with progressively more efficient component configurations, we estimate the typical gaming computer (including display) to use approximately 1400 kWh/year, which is equivalent to the energy use of ten game consoles, six standard PCs, or three refrigerators. The more intensive user segments could easily consume double this central estimate. While gaming PCs represent only 2.5 % of the global installed PC equipment base, our initial scoping estimate suggests that gaming PCs consumed 75 TWh/year ($10 billion) of electricity globally in 2012 or approximately 20 % of total PC, notebook, and console energy usage. Based on projected changes in the installed base, we estimate that consumption will more than double by the year 2020 if the current rate of equipment sales is unabated and efficiencies are not improved. Although they will represent only 10 % of the installed base of gaming platforms in 2020, relatively high unit energy consumption and high hours of use will result in gaming computers being responsible for 40 % of gaming energy use. Savings of more than 75 % can be achieved via premium efficiency components applied at the time of manufacture or via retrofit, while improving reliability and performance (nearly a doubling of performance per unit of energy). This corresponds to a potential savings of approximately 120 TWh/year or $18 billion/year globally by 2020. A consumer decision-making environment largely devoid of energy information and incentives suggests a need for targeted energy efficiency programs and policies in capturing these benefits.     

Energy savings from the Minnesota low-income weatherization programme

The 26 local Community Action Agencies in Minnesota administer a federal programme to audit and retrofit homes occupied by low-income households. This programme aims to improve the thermal performance of these homes and so reduce the economic hardship faced by these households because of high and rising fuel prices. A key question concerns the actual energy savings that can be attributed to the programme. The work reported here involved collection and analysis of fuel consumption records from low-income households throughout Minnesota. Data were obtained from 59 households that had received weatherization services and from 37 households that were eligible for assistance but had not yet been weatherized. Comparisons of fuel consumption across the two groups for the 1976–1977 and 1977–1978 winters showed that the average saving due to weatherization was 13% of total household energy use. Based on fuel prices that prevailed in 1979, the cost of weatherization is likely to be repaid with lower fuel bills in 3–4 years.     

Energy efficiency as a preferred resource: evidence from utility resource plans in the Western US and Canada

This article examines the future role of energy efficiency as a resource in the Western US and Canada, as envisioned in the most recent resource plans issued by 16 utilities, representing about 60% of the region’s load. Utility and third-party-administered energy-efficiency programs proposed by 15 utilities over a 10-year horizon would save almost 19,000 GWh annually, about 5.2% of forecast load. There are clear regional trends in the aggressiveness of proposed energy savings. California’s investor-owned utilities (IOUs) had the most aggressive savings targets, followed by IOUs in the Pacific Northwest, and the lowest savings were proposed by utilities in Inland West states and by two public utilities on the West Coast. The adoption of multiple, aggressive policies targeting energy efficiency and climate change appears to produce sizeable energy-efficiency commitments. Certain specific policies, such as mandated energy savings goals for California’s IOUs and energy-efficiency provisions in Nevada’s Renewable Portfolio Standard, had a direct impact on the level of energy savings included in the resource plans. Other policies, such as revenue decoupling and shareholder incentives and voluntary or legislatively mandated greenhouse gas emission reduction policies, may have also impacted utilities’ energy-efficiency commitments, though the effects of these policies are not easily measured. Despite progress among the utilities in our sample, more aggressive energy-efficiency strategies that include high-efficiency standards for additional appliances and equipment, tighter building codes for new construction and renovation, as well as more comprehensive ratepayer-funded energy-efficiency programs are likely to be necessary to achieve a region-wide goal of meeting 20% of electricity demand with efficiency in 2020.

Energy assessment of the Portuguese meat industry

The meat product industries play a major role in many global economies. In several countries, it is the industry with a higher economic weight within the food industries. As refrigeration systems are indispensable within the production processes, it is important to improve the overall energy efficiency in order to reduce the electricity consumption in these industries. The electrical energy consumption of the Portuguese meat industries is evaluated in this paper. The field study shows that electrical energy accounts for 66.5 % of the overall energy consumption in slaughterhouses, 85 % in sausage houses and 92.5 % in ham industries. Relatively to the refrigeration systems of these industries, results show that the average compressor nominal power per unit of cold room volume is comprised between 0.072 and 0.043 kW/m³. The average value of the specific electrical energy consumption for the slaughterhouses was 149 kWh/ton_HSCW, 660 kWh/ton_RM for sausage houses and 1208 kWh/ton_RM for ham production industries. Finally, a potential reduction of the electricity consumption based on simple energy efficiency measures was estimated in 24 % for the slaughterhouses, 13 % for the sausage houses and 8 % for the ham industry.     

A MEPS is a MEPS is a MEPS: comparing Ecodesign and Top Runner schemes for setting product efficiency standards

Both Top Runner in Japan and Ecodesign in the European Union are schemes to set requirements on the energy efficiency (minimum efficiency performance standards, MEPS) of a variety of products. This article provides an overview of the main characteristics and results of both schemes and gives recommendations for improving them. Both schemes contribute significantly to the energy efficiency targets set by the European Commission and the Japanese government. Although it is difficult to compare the absolute levels of the requirements, comparison of the relative improvements and of the savings on household electricity consumption (11 % in Japan, 16 % in the EU) suggest they are in the same range. Furthermore, the time needed to set or review requirements is in both schemes considerable (between 5 and 6 years on average) and the manageability increasingly will become a challenge. The appeal of the Top Runner approach is that the most efficient product (Top Runner) sets the standard for all products at the next target year. Although the Ecodesign scheme includes the elements for a Top Runner approach, it could exploit this principle more explicitly. On the other hand, the Top Runner scheme could benefit by using a real minimum efficiency performance standard instead of a fleet average. This would make the monitoring and enforcement more simple and transparent, and would open the scheme for products where the market situation is less clear.