Questionnaire

The aim of the survey was to capture the most important influences on residential energy consumption. Towards this aim, a questionnaire that is suitable for a self-administered mail survey but captures the most important influences on residential energy consumption as well as lifestyle dimensions and attitudes towards energy consumption had to be designed.

The electrical consumption of a household is determined by the kind and num-ber of the electrical appliances and the usage of these devices. In contrast to direct questions about energy consumption, where previous studies report a large portion of missing values, adult members of an household can be expected to know about most devices to be found in their household and about daily routines regarding appliance usage and household tasks. Therefore the most energy relevant house-hold tasks and appliances have been identified and interviewees were asked directly about their habits regarding these tasks and the kind and quantity of appliances inside their household (see Chapter 2).

When excluding electric space heating and electric water heating the largest share of residential electricity consumption is due to refrigerators, followed by lighting, washing and drying, cooking, and entertainment (see Chapter 2). The questionnaire therefore concentrated on these areas and asked for the number of refrigerators, television-sets, personal computers, dish-washers, washing-machines and tumble dryers present in the household. For some devices we also asked for their age and their classification in the EU energy efficiency label or for their size (e.g. height for refrigerators or diagonal of television screen) in order to gather further information about the energy consumption.

The amount and kind of electronic equipment that can be found in a household

seems to be explained better by lifestyle factors than only by income and other so-ciodemographics. That is one of the reasons why lifestyle typologies are prominent in the field of marketing and consumer research (e.g. Sinus-Sociovision). Unfor-tunately, these companies tend not to give away their data for free, so we have to refer to secondary analysis for a first estimate of the variation of household appli-ances in regard to lifestyle groups. According to Bundesministerium für Umwelt, Naturschutz und Reaktorsicherheit (2008), who conducted a study on environmen-tal awareness in cooperation with Sinus-Sociovision 52 % of the respondents toenvironmen-tally agree when asked if energy efficiency plays a role in the purchase of household ap-pliances, 36 % agree. This shows a strong respondents effect of social desirability towards agreement; nevertheless, there seems to be a significant variation between lifestyle milieus in the response to this question: While 84 percent of the conser-vative¹ totally agree, only 33 % of the materialistic and no more than 21 percent of the hedonists share this view. These groups also tend to watch less for dura-bility when buying new equipment. At the same time, there is a largely discussed gap between environmental awareness and behavior suggesting a stronger focus on actual behavior for the survey, so we ask for the knowledge of specific energy efficiency labels and for the energy efficiency of several household items in use.

Further, the questionnaire asked for weekly use rates of stoves and ovens, dish-washers, washing-machines and tumble dryers and for the average daily use of television-sets, personal computers, stoves, ovens, and hifi-systems. To capture differences in lighting, a question about the percentage of energy efficient lamps in the household was included. Since it was intended to use the data to model load-curves, information about daily routines had to be collected that enable to identify times of absence and inactivity, where no devices will be switched by the household members. So it was asked when the last person in the household usually will go to sleep and at what time the first person to get up will usually do so. We also asked for how much time during the day somebody is present at home. To get information about cooking habits, the questionnaire contains questions for the average number of meals prepared at home, if lunch and dinner is usually prepared at home and if it is rather a cold meal or a warm meal, as well as if there is a specific

1These terms refer to the Sinus-Milieus^®

5.1. Survey time when dinner and lunch are usually taken.To estimate the energy demand for warm water consumption the average amount of showers and baths taken per week was asked.

To get information about the energy demand for space heating, questions about the building type and building age were included and it was asked for the living area, type of heating system and ventilation habits as well as thermostat settings.

The questionnaire of course also contained information about sociodemographic variables, lifestyle items, and attitude scales and asked directly for the residential energy consumption for space heating and consumption of electricity in terms of physical units and monetary costs, in order to see if and how much the chosen approach is really able to reduce the missing values that result from direct questions about energy consumptions.

Since thermostat settings and ventilation are the most prominent user influences on the energy consumption for space heating (Koch et al., 2008), useful indicators for these behaviors that can be and collected using a standardized questionnaire are needed. The results of psychological Mack (2007) and sociological Hinding (2002) research indicates, that a big part of energy relevant behavior is subject to habituation and not necessarily consistent in different areas, i.e. someone might keep his room at a modest temperature, but also use to open the windows very often and might thus use more energy for space heating than someone who is keeping his flat at a rather high temperature, but has energy saving ventilation habits. The questionnaire therefore contains simple questions about ventilation habits and thermostat settings that can be expected to have significant impact on the energy consumption and can be collected with a mail survey.

Besides ventilation habits and thermostat settings, the building structure, of course, strongly determines the energy consumption for space heating and can be influenced by the user by retrofitting measures. In France and Germany there are different support schemes and governmental subsidies for retrofitting; the most important are the KfW-Förderprogramme in Germany and the Certificats d’économies d’énergie in France. In order to get information about differences between sociodemographic and lifestyle groups in regard to retrofitting activities and the usage of financial aids, questions about performed retrofitting measures

and usage of subsidies have been included in the questionnaire.