The effect of occupancy and building characteristics on energy use for space and water heating in Dutch residential stock

Abstract

As a consequence of the improved quality of thermal properties of buildings due to energy regulations, overall energy use associated with building characteristics is decreasing, making the role of the occupant more important. Studies have shown that occupant behaviour might play a prominent role in the variation in energy consumption in different households but the extent of such influence is unknown. The impact of the building's thermal characteristics on space heating demand has been well studied. There is however, little work done that incorporates the impact of consumer behaviour. This study aims to gain greater insight into the effect of occupant behaviour on energy consumption for space heating by determining its effect on the variation of energy consumption in dwellings while controlling for building characteristics. The KWR database from the Ministry of Housing in the Netherlands was used. This study showed that occupant characteristics and behaviour significantly affect energy use (4.2%), but building characteristics still determine a large part of the energy use in a dwelling (42%). Further analysis showed that some occupant behaviour is determined by the type of dwelling or HVAC systems and, therefore, the effect of occupant characteristics might be larger than expected, since these determine the type of dwelling.

Introduction

Diverse factors have caused an increase in energy use throughout the world. Globalisation has spread the lifestyle of the most developed Western countries worldwide, changing the expectations about the quality of life in many societies to a point where sustainability is no longer possible on a large scale. One of the aspects of lifestyle that causes a high environmental burden in developed countries is the use of energy in buildings. Worldwide, the building industry and the built environment are some of the largest contributors to energy and material use. In the northern part of the European Union, 41% of total final energy consumption comes from buildings, with 30% being used in residential buildings [1]. According to EuroAce [2] (57)% of the energy consumed in buildings is used for space heating, 25% for hot water, 11% for lighting and electrical appliances, and 7% for cooking.

Due to the importance of a good quality of the indoor environment and the problems caused by high energy consumption, governments have enacted a series of policies and regulations aimed at increasing the energy efficiency of dwellings and ensuring a good indoor environment. An example of such initiatives is the EPBD, which from 2003 obliged all European member states to implement performance-based energy regulations aimed at decreasing energy consumption in buildings in relation to heating, cooling, ventilation, lighting and domestic hot water. In addition, efforts to construct low energy buildings can be observed in several projects and studies worldwide. Nevertheless, energy savings due to energy conservation measures are suspected to be lower in reality than predicted [3], [4], [5].

The importance of building characteristics has been determined in diverse studies. Leth-Petersen and Togeby [6] studied the influence of building regulations on energy use, finding that they have been important in reducing energy consumption in new buildings. As a consequence, overall energy use associated with building characteristics is decreasing, making the role of the occupant even more important [4], [7], [8]. In the Netherlands, Beerepoot and Beerepoot [9] found that energy performance regulations have been successful in conserving energy. Nevertheless, the variation in energy consumption is still large for dwellings with the same characteristics.

Studies have shown that occupant behaviour might play a prominent role in the variation in energy consumption in different households [3], [10], but the extent of such influence is still unknown. The impact of the building's thermal characteristics on space heating demand has been well studied, quantified and validated from the viewpoint of individual buildings and building simulation, and can now be found in various handbooks (for example, [11], [12], [13], [14]). There has, however, been little work done on the impact of the thermal characteristics of building stock from a statistical perspective. There is also little work that incorporates the impact of consumer behaviour [4]. In addition, there is little information on the effect of occupant behaviour taking into account building and household characteristics.

This study aims to gain greater insight into the effect of occupant behaviour on energy consumption for space heating by determining its effect on the variation of energy consumption in dwellings while controlling for building characteristics. In addition, this study aims to determine the respective effect of building and occupant attributes on energy use, and the relationship between them. The research questions of the study are:

• What are the most important characteristics of the building and occupancy (defined as household characteristics and occupant behaviour) that affect energy use for space heating?

• How much of the variation in energy use can be explained with a model combining both types of variables?

• What is the relationship between building and occupancy characteristics?

Section 2 will provide a literature survey which will determine the parameters used in the model, while Section 3 will present the analysis methods and data used. Section 4 will present the results of the statistical analyses, firstly introducing the differences in energy use for different types of dwellings with different levels of insulation, and secondly introducing the results of the regression analysis and its comparison with a model containing only occupant-related variables. Section 5 will provide the conclusions of the study and make recommendations for further research.