Home Energy Use Research Articles

Design Challenges and Opportunities for Eco-Feedback in the Home

Domestic energy conservation is critical to reducing energy demand and greenhouse gas emissions. Personal visualization has a role to play in the design of appropriate feedback for encouraging more effective home energy use, but the unique nature of residential energy informatics introduces new design issues. This article reviews current approaches and discusses unaddressed challenges related to better conceptual models, context, enhanced communicative scope, and functional aesthetics. Based on a proposed theoretical framework, the author identifies important gaps in the current design space of residential energy visualizations related to richer data models, a broader concept of context, an enhanced communicative scope, and a better ecological fit in the home.

Energy efficiency and the misuse of programmable thermostats: The effectiveness of crowdsourcing for understanding household behavior

Programmable thermostats are generally sold as energy-saving devices controlling heating and cooling systems, but can lead to energy waste when not operated as designed by the manufacturers. We utilized Amazon Mechanical Turk, an online crowdsourcing service, to investigate thermostat settings and behavior in households. We posted a survey and paid respondents to upload pictures of their thermostats to verify self-reported data. About 40% of programmable thermostat owners did not use programming features and 33% had programming features overridden. Respondents demonstrated numerous misconceptions about how thermostats control home energy use. Moreover, we found that 57% of households were occupied nearly all the time, limiting the potential energy savings. The study revealed flaws in self-reported data, when collected solely from traditional surveys, which raises concerns about the validity of current thermostat-related research using such data. “Ground truth” temperature data could now be available in homes with Internet-connected thermostats. Online crowdsourcing platforms emerge as valuable tools for collecting information that would be difficult or expensive to obtain through other means. Advantages over traditional surveys include low-cost, rapid design–implementation–result cycle, access to diverse population, use of multimedia. Crowdsourcing is more effective than alternative online tools due to easier recruitment process and respondents’ reputation system.

Would an Energy Conservation Nudge in Hotels Encourage Hotel Guests to Conserve?

Utility companies achieved an average reduction of 2.5 percent in home energy use through an energy conservation nudge that provides feedback on energy consumption as compared with neighbors. This study investigated whether hotels can replicate this effect with their guests. A 2 (valence of electricity consumption) × 2 (comparison subject) experimental design with a control group was used with 1,000 respondents reporting their behavioral intentions in response to the energy conservation nudge in a scenario-based experiment. The results of a one-way analysis of variance (ANOVA) revealed that behavioral intentions toward electricity conservation were pronounced when the nudge was provided (regardless of the valence of electricity consumption and the comparison subject). The results of an analysis of covariance (ANCOVA) with an energy conscious level as a covariate confirmed the effectiveness of the nudge on electricity conservation. The results indicate that hotels can achieve guest-driven electricity efficiency when an appropriately designed nudge is supplied to guests. The implications of the study are also discussed.

Limited Attention and the Residential Energy Efficiency Gap

Inattention may be an important contributor to the energy efficiency gap and may be particularly acute in residential buildings where many different features will determine a home's energy use. Energy audits can provide information on how to reduce energy loss in a home, but the use of audits is rare. We use data from a national survey of 1700 homeowners to study the factors affecting a home owner's choice to have an audit. We create an index of energy inattention for our survey respondents. This index and two additional behavioral factors prove to be important determinants of the audit choice.

His, hers or both's? The role of male and female's attitudes in explaining their home energy use behaviours

Building energy research has historically overlooked the role of attitudes, instead focusing on building and socio-demographic influences. Even when attitudes are measured, usually, the attitudes of just one household member are measured even though household energy consumption is the result of actions of all household members. This research explored first whether attitudes could help explain heating usage and second whether the attitudes of a couple could explain more of the variability in heating behaviour than the attitudes of one partner. The attitudes towards home heating energy use (i.e. attitudes towards thermal comfort, economical with energy, industry and technology's role and individual's role) of 128 English couples were used in this study. Together with building and socio-demographics, attitudes were examined to explain heating temperatures and durations, which were derived from temperature sensors placed in the homes in 2007–2008. The results showed that attitudes helped explain heating temperatures and durations, even when building and socio-demographic variables were controlled. Economical with energy was the most highly identified influence on heating behaviours, with thermal comfort a close second. In households that included a couple, combined attitudes of both partners explained heating usage behaviours more accurately than the attitudes of either male or female only.

A Feasibility Study on Occupants' Behaviour and Energy Usage Patterns and Its Potential Integration with Building Information Modelling

Understanding how occupants manage their energy use in homes and how their behaviour influence household energy consumption in domestic environments has been challenging. There seems to be several major factors contributing towards achieving optimal performance in designing, constructing and maintaining a sustainable home using Building Information Modelling (BIM) based approaches. This study focuses on investigating the relationship between user behaviour and energy consumption through the in-depth analysis of energy usage patterns collected from a selected affordable terraced house in Prestwick, Scotland, as an initial attempt towards the future integration with BIM systems. For the purpose of this feasibility study, indoor temperature, relative humidity and CO2 sensors, as well as a gas-electricity-water utility monitor were installed in the selected home occupied by a working class nuclear household. The study encompasses the analyses of energy usage patterns in their daily life. It is confirmed that domestic energy consumption is affected by the occupants' presence and behaviour. Moreover, this paper discusses a possibility that the energy prediction approach taken in this study could work alongside BIM systems applied for housing suppliers' design decision-making on the delivery of energy efficient homes of the future.

Retrofitting social housing in the UK: Home energy use and performance in a pre-Community Energy Saving Programme (CESP)

Improving household energy efficiency is regarded as key to significantly curtailing domestic greenhouse gas emissions. Various policy instruments have been introduced to retrofit the existing domestic building stock in the UK; however, many fail to acknowledge the significant role that occupants’ lifestyle play in energy use. The research discusses the results of a survey questionnaire administered to the residents of one of the pilot CESP schemes in Aspley, Nottingham. Factors affecting domestic energy consumption are explored, some of which relate to the building design, while others are under the direct control of the occupants. Significant findings related to home performance, home energy use, and tenants’ lifestyle are investigated in the first phase of the research. The total number of responses to the survey represents 10% of around 900 properties eligible for the CESP scheme that have not been approached for the scheme uptake. It is evident from the survey results that the majority of the sample is aware of the basic energy-saving actions in everyday life but are not likely to take up the more difficult actions. In summary, retrofit programmes will reduce carbon emissions to some degree, whereas the bigger challenge is addressing habitual household energy consumption.

Exploring perceived control in domestic electricity demand-side response

Research into consumer acceptance of domestic electricity demand-side response (DSR) highlights loss of personal control as a key concern. This UK focus group study explored people's perceived control in relation to home energy use and DSR. Three DSR offerings were discussed: fixed and dynamic time of use (TOU) pricing and direct load control. Participants' main motivations for control were costs, comfort, time/flexibility and autonomy. The majority viewed a fixed TOU tariff as increasing personal control, particularly over costs. Dynamic TOU pricing divided opinion, with some perceiving more control over costs, while others were concerned about ease of use, requirement for automation, predictability and flexibility. Almost everyone saw direct load control as reducing their control, although some framed this only in terms of control over appliances, while others were concerned about their overall autonomy. Implications for future research and the design, targeting and communication of DSR products are discussed.

Progress on Ambitious Goals of Vision 2020: Tree Planting Conserves Home Energy Use: SFI® Invests in Forest Conservation Research: Ban on Log Exports May Cripple Industry; Export Quotas May Help: U.K. Forester Recognized by the Canadian Institute of Forestry: CIFOR Scientists Contribute to Global Climate Policy Research

Progress on Ambitious Goals of Vision 2020: Tree Planting Conserves Home Energy Use: SFI^® Invests in Forest Conservation Research: Ban on Log Exports May Cripple Industry; Export Quotas May Help: U.K. Forester Recognized by the Canadian Institute of Forestry: CIFOR Scientists Contribute to Global Climate Policy Research

Effect of thermostat and window opening occupant behavior models on energy use in homes

Existing dynamic energy simulation tools exceed the static dimension of the simplified methods through a better and more accurate prediction of energy use; however, their ability to predict real energy consumption is undermined by a weak representation of human interactions with the control of the indoor environment. The traditional approach to building dynamic simulation considers energy consumption as fully deterministic, taking into account standardized input parameters and using fixed and unrealistic schedules (lighting level, occupancy, ventilation rate, thermostat set-point). In contrast, in everyday practice occupants interact with the building plant system and building envelope in order to achieve desired indoor environmental conditions. In this study, occupant behavior in residential building was modelled accordingly to a probabilistic approach. A new methodology was developed to combine probabilistic user profiles for both window opening and thermostat set-point adjustments into one building energy model implemented in the dynamic simulation tool IDA Ice. The aim of the study was to compare mean values of the probabilistic distribution of the obtained results with a singular heating energy consumption value obtained by means of standard deterministic simulations. Major findings of this research demonstrated the weakness of standardized occupant behavior profile in energy simulation tools and the strengths of energy models based on measurements in fields and probabilistic modelling providing scenarios of occupant behavior in buildings.

A Novel Current Sensor for Home Energy Use Monitoring

This paper presents a novel magnetic sensor array based technique for measuring currents in a group of enclosed conductors. It is designed specifically for monitoring the real-time power consumptions of North American homes. The technique consists of three key components: magnetic field sensors deployed in close proximity of the power conductors to be measured; algorithms to compute the conductor currents based on the magnetic fields measured; a simple, integrated sensor calibration and communication scheme. Prototype devices have been developed based on the technique. Extensive lab and field tests have demonstrated that the technique can provide adequate current measurements for residential homes. Combining with the non-intrusive load monitoring methods, the proposed measurement technique represents an attractive platform to create a complete home energy use tracking system.

Smart home energy management system including renewable energy based on ZigBee and PLC

As home energy use is increasing and renewable energy systems are deployed, home energy management system (HEMS) needs to consider both energy consumption and generation simultaneously to minimize the energy cost. This paper proposes a smart HEMS architecture that considers both energy consumption and generation simultaneously. ZigBee-based energy measurement modules are used to monitor the energy consumption of home appliances and lights. A PLC-based renewable energy gateway is used to monitor the energy generation of renewable energies. The home server gathers the energy consumption and generation data, analyzes them for energy estimation, and controls the home energy use schedule to minimize the energy cost. The remote energy management server aggregates the energy data from numerous home servers, compares them, and creates useful statistical analysis information. By considering both energy consumption and generation, the proposed HEMS architecture is expected to optimize home energy use and result in home energy cost saving.

Life-cycle energy implications of different residential settings: Recognizing buildings, travel, and public infrastructure

The built environment can be used to influence travel demand, but very few studies consider the relative energy savings of such policies in context of a complex urban system. This analysis quantifies the day-to-day and embodied energy consumption of four different neighborhoods in Austin, Texas, to examine how built environment variations influence various sources of urban energy consumption. A microsimulation combines models for petroleum use (from driving) and residential and commercial power and natural gas use with rigorously measured building stock and infrastructure materials quantities (to arrive at embodied energy). Results indicate that the more suburban neighborhoods, with mostly detached single-family homes, consume up to 320% more embodied energy, 150% more operational energy, and about 160% more total life-cycle energy (per capita) than a densely developed neighborhood with mostly low-rise-apartments and duplexes. Across all neighborhoods, operational energy use comprised 83 to 92% of total energy use, and transportation sources (including personal vehicles and transit, plus street, parking structure, and sidewalk infrastructure) made up 44 to 47% of the life-cycle energy demands tallied. Energy elasticity calculations across the neighborhoods suggest that increased population density and reduced residential unit size offer greatest life-cycle energy savings per capita, by reducing both operational demands from driving and home energy use, and from less embodied energy from construction. These results provide measurable metrics for comparing different neighborhood styles and develop a framework to anticipate energy-savings from changes in the built environment versus household energy efficiency.

Privacy-Enhanced Data Aggregation Scheme Against Internal Attackers in Smart Grid

According to related research, energy consumption can be effectively reduced by using energy management information of smart grids. In smart grid architecture, electricity suppliers can monitor, predicate, and control energy generation/consumption in real time. Users can know the current price of electrical energy and obtain energy management information from smart meters. It helps users reduce home's energy use. However, electricity consumptions of users may divulge the privacy information of users. Therefore, privacy of users and communication security of the smart grid become crucial security issues. This paper presents a secure power-usage data aggregation scheme for smart grid. Electricity suppliers can learn about the current power usage of each neighborhood to arrange energy supply and distribution without knowing the individual electricity consumption of each user. This is the first scheme against internal attackers, and it provides secure batch verification. Additionally, the security of the proposed scheme is demonstrated by formal proofs.

Influencing Carbon Behaviours: What Psychological and Demographic Factors Contribute to Individual Differences in Home Energy Use Reduction and Transportation Mode Decisions?

As pressure mounts on countries to reduce carbon emissions, there is increasing interest in understanding what drives “carbon behaviours”, in order to inform behavioural change policies. This study examined the impact of psychological and demographic variables, on “carbon behaviours”. Secondary data analysis was carried out to investigate the antecedents of residential energy use reduction behaviours and choice of transportation mode for commuting and grocery shopping. Models explained 18.2% and 25.2% of variance in energy use and transport behaviours respectively. Being concerned about climate change and having an environmental identity increased household energy reduction behaviour but did not significantly affect travel mode choices. The antecedents of travel mode decisions were attitudes towards the travel mode itself, and demographic and structural variables such as income and distance travelled. Findings suggest that using “green” messaging will help encourage behavioural change in energy use, but contribute little to encouraging change in travel mode decisions.

Lighting Scheduling for Energy Saving in Smart House Based on Life Log Data

Efficient energy consumption in homes is one of key elements of sustainable healthy residential living. This thesis deals with decision-making method and procedure for home energy use scheduling designed to boost energy efficiency. Home energy use scheduling is a complex task that combines various data for decision-making. To carry out the task, this study used the idea of utilizing ‘life log data,’ which is recording and storing daily routines. Life log data is recorded and stored in a metrics developed through a literature study and it contains 5W1H data (Who, When, Where, What, Why, How). Through the 5W1H data, lifestyle of residents can be analysed to determine the right services for them. The processes are as follows; House environments, Service determined, Similarity analysis, Data filtering, Smart service. As the life log data is developed by human's experience, this system makes it possible for one to one personalized service. And it can be possible personal energy savings at home. One of the key merits in relation to the utilization of the life-log data is that it can provide a customized one-on-one service reflecting the behavioural patterns and the lifestyles of a resident.

Promoting low-carbon home adaptations and behavioural change in the older community

The Government has set an ambitious target to cut the UK's carbon emissions by 80% by year 2050. To meet these targets, action is needed in the residential sector with 27% of the UK's CO2 emissions coming from energy use in homes. While working towards zero-carbon new homes, refurbishment of the existing housing stock to advanced, low-carbon standards is essential. In this process the involvement of all stakeholders and behavioural change of occupants to low-carbon life styles are primary factors. This paper presents the findings of an Engineering and Physical Sciences Research Council Public Engagement project (2009–2010) carried out to promote low-carbon home adaptations and behaviour change among the elderly. A number of engagement events were held to increase the awareness of environmental upgrading of homes, energy-efficiency measures, financial support available and low-carbon life styles. A feedback process collected information on sustainable actions taken by the attendees 3–6 months after the initial events. A coding method was designed to analyse the questionnaire responses. The results illustrated that many had made changes in their lives since attending the events, are planning to change or have encouraged someone else they know to make a change in their lives to be more sustainable.

Children, parents and home energy use: Exploring motivations and limits to energy demand reduction

While almost 30% of UK households include children, little research has attempted to present children's perspectives on home energy use. This study used focus groups with children and parents at two primary (elementary) schools in London, UK, to explore home energy use and energy feedback. Energy was found to be a little-discussed subject at home. Children derived more motivation to save energy from responsibility conferred by school activities than other (e.g. environmental) concerns, and some connected energy saving with dangers of using electricity (e.g. fire). Material and social constraints (e.g. access to outside space, parents' environmental attitudes) meant that it was sometimes difficult for children to save energy even when motivated. However, parents showed greater inclination to pay attention to energy saving when framed as supporting their child's learning than as a financial or environmental concern. Children were disinclined to reduce energy-consuming activities such as watching television, and while parents complained about children's energy use most saw it as a low priority issue. Policy implications of these findings are considered, and the approach employed is argued to be an effective way of investigating children's perceptions around energy use.

Heating patterns in English homes: Comparing results from a national survey against common model assumptions

Heating patterns and temperatures are among the most important determinants of English home energy use. Consequently, building stock models, widely used for informing UK energy policy, are highly sensitive to the assumptions they make on how occupants heat their homes. This study examined heating patterns in English living rooms and compared them to model assumptions. A time-series of winter spot temperature measurements was translated into statements of the heating system being on or off during weekdays and weekend days, and the heating demand temperature estimated. The analysis showed that weekdays and weekend days are far more similar than commonly assumed. Contrary to model assumptions, homes were frequently heated outside assumed heating hours and not all homes were heated at the same time or followed the same pattern. The estimated demand temperature was about 20.6 °C, and the average temperature during heating periods was about 19.5 °C, both lower than the commonly assumed 21 °C used in models. Significantly, variability between homes in demand temperature and hours of heating was substantial. The results indicate the need to revisit some assumptions made in building stock models, and to take account of variability between homes when aiming at predicting space heating demand for an individual home.

People and Energy: A design‐led approach to understanding everyday energy use behaviour

Reducing home energy use is a major societal challenge, involving behaviour change alongside infrastructure improvements. However, many approaches lump ‘energy demand’ together as something homogeneous, addressable primarily through quantitative feedback, rather than basing interventions on an understanding of why people use energy as they do. Our contention is that people don't set out to ‘use energy’: its use is a side effect of solving everyday problems, meeting needs for comfort, light, cooking, cleaning, entertainment, and so on.Design researchers at the Royal College of Art have been carrying out ethnographic research with a diverse range of householders, investigating nuances of daily interactions with heating and lighting, meters and appliances—alongside people's understanding of energy and how their actions affect its use. Insights, integrated with household monitoring data, will inform the co‐design of prototype products and services to help people reduce their energy use while meeting needs.