R EFLEXIONES SOBRE EL USO DE LA LAPTOP XO

Most of the published trials involve standalone energy monitors connected to standard meters; as a result, most studies have involved electricity consumption, not gas. Few trials exist which used an energy monitor to display household gas consumption, although there are examples from North America, the Netherlands and Australia. Hutton et al. (1986) and Van Houwelingen and Van Raaij (1989) were pioneers in using in-home displays to provide daily feedback on residential gas consumption.

Hutton et al. (1986) developed a simplistic numerical in-home display called the Energy Cost Indicator (ECI). ECI displayed current, next hour, rolling day, monthly and previous day costs to 280 homes in California, Quebec and British Columbia. The rollout of the ECI was combined with provision for extensive written feedback and guidance, with which a further 263 homes were supplied; 241 properties acted as the control sites. The report concluded that there was a significant 5.1% electricity saving for the homes in Quebec. Incidentally these were electricity only properties, had the highest energy knowledge and were in the coldest of the three trial regions. Gas savings were significant at 5% in British Columbia, compared to a group who had energy efficiency information (if an outlier was excluded), and in California for income quartile Q3 (middle class, educated). A comparison group of 263 homes (75 using gas in addition to electricity) received advice only and did not make significant savings in either gas or electricity relative to the 241 control homes. None of the effects were persistent. However, the properties given an ECI were also given additional learning material, so it is impossible to distinguish which intervention yielded the results.

Around the same time as the ECI trials in North America, in the Netherlands Van Houwelingen and Van Raaij (1989) investigated a range of interventions aimed at influencing conservation behaviour, one of which was an energy monitor similar to the ECI used by Hutton et al. (1986), referred to as the ‘Indicator’, which

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displayed household gas consumption. The Indicator showed two bar graphs, one depicting actual gas use and one displaying the reference normative value, normalised using external air temperature. The participants were 285 renting households who volunteered for the trial. With daily feedback through the energy monitor, a 12.3% reduction in natural gas use was achieved, more than the stated 10% conservation goal.

Ueno et al. (2006) constructed and used an on-line Energy Consumption Information System, called the ECOIS II, which they used 10 households in Kyoto Japan. The ECOIS II gave the occupants a detailed breakdown and array of information on city-gas, electricity consumption and room temperature. The consumption data was collected from the 10 households in Kyoto, Japan and the data was transferred to and analysed in a laboratory-based computer before being sent to an information terminal (a B5 sized laptop computer) in each house by e-mail. Although the ECOIS II is not technically typical of the standalone in- home energy monitor as used by the other researchers discussed here, it is pertinent to include Ueno et al.’s (2006) findings, because they conducted one of the few modern trials that included giving feedback to occupants concerning their gas consumption.

Comparisons of energy consumption before the installation of ECOIS II (period 1) and after the installation (period 2) revealed that the power consumption of many appliances and energy consumption of the whole house was reduced. Total power consumption decreased by 18% and the total city-gas consumption decreased by 9%, averaged over the 10 houses, with the ECOIS II. However, the 9 control homes without the feedback laptop experienced a total electricity consumption decrease of 5% and the total city-gas consumption increased by 0.4%. Ueno et al. (2006) conclude that the installation of ECOIS II had a certain influence on the energy-saving awareness of the residents.

A smaller study by SenterNovem (UC Partners 2009) involved interviewing 18 volunteer Dutch households, providing them with energy advice and asking them to make weekly meter readings for three months in winter. These households reduced their electricity usage by 3% and gas by 2% (statistical significance was

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not tested). A further 18 households received the same intervention but also volunteered to set themselves a target for energy savings and accept a new design of energy monitor on trial (showing current, highest, lowest, monthly and yearly electricity and gas consumption and cost, plus the conservation target and savings). This group reduced electricity usage by 6% and gas by 12%. However, either the savings target or the energy monitor or the combination of the two might have been responsible. The report suggests that those with a real time display will deliver superior energy saving results compared with the other methods.

Black et al. (2009) used an energy monitor in a study of student properties in New South Wales, Australia. There were 18 intervention cottages and 14 control cottages, each with 8 students per cottage. An energy consumption monitor was used in phase one of a three phase electricity and gas consumption intervention project. The phases spanned 7, 8 and 11 weeks respectively and occurred at different times of the year. The results for the use of an energy monitor showed overall electricity savings of 24% compared to the 14 control cottages, but those cottages with more electrical appliances experienced only 4% savings. The figures for gas consumption increased by 10% in the energy monitor group. In phases two and three (when an energy monitor was accompanied by social marketing on energy reduction), savings improved to 13% and 19% reductions in gas consumption respectively for the display groups.

Black et al. (2009) suggest that this may be attributed to problems with the smart meters’ communication protocols. Further technical issues experienced during the trial resulted in a variable number of cottages providing useable data: those with energy monitor electricity data n=9, gas data n=7, controls with electricity data n=14, gas data n=12. Black et al. (2009) conclude that providing separate tools for real-time feedback display and social marketing support strategies has a significant influence on energy consumption behaviours, and enhances intrinsic motivations.

Trials like the one conducted by SenterNovem (UC Partners 2009) serve to support the current academic thinking that households will produce greater savings when they use an energy monitor rather than indirect methods of energy

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awareness. However, Black et al. (2009) supports the view that an energy monitor’s ability to reduce domestic energy consumption is increased when it is accompanied by written awareness documentation.