Conventional new buildings in OECD countries with a history of building codes save about 50 % of energy compared to average buildings in the building stock. This improvement, however, is not enough to create a building standard with low lifetime costs nor to reach long-term climate protection targets. Much higher energy savings can already be achieved through proven high-efficiency building concepts bringing net economic benefits among other advantages.
A strategic approach to integrated building design is the key to achieving these high-energy savings at low or no extra cost in residential buildings. In our paper we describe the "Easy Efficiency Approach", which can reduce primary energy consumption by 40 to 60 % compared to conventional new building standards, or by 70% to 80% when compared to the primary energy consumption of the existing building stock, and should be regarded as the minimum. This strategy focuses on low-cost options, mainly passive options. Although it can already significantly reduce energy consumption, this first step will not be sufficient to reach long-term climate protection goals. It is thus necessary to implement and support what we call an "Advanced Efficiency Approach", with savings up to 90% , as compared to new building standards, as soon as possible to avoid lock-in effects. Further improvements, especially through the active use of renewable energies, reduce the net primary energy demand to 0 % and beyond.
According to the chosen strategy clearly defined energy performance ranges, with reference to possible savings, for different climate zones worldwide are given. In verifying this approach simulations with BAT (Best Available Technologies) buildings of different types (single family, multi family, high rise) were carried out in close cooperation with project partners. This data has also been verified through an empirical database of built examples both for energy consumption as well their economic soundness.
The efficiency strategy to exploit the potential for energy savings in buildings still is applied rather slowly in most countries. In addition, there are indications that energy savings are partly compensated particularly by wealth but also rebound effects, the "empty nest" (persistence of elderly people and couples in family homes), and cohort effects (e.g. vintages of people or buildings). In Germany, as in other European countries, the existing trend in housing is a continuously growing floor space per capita. Over the last decades it expanded from about 20 m2 in 1960 to currently 45 m2 per person. Forecasts expect a further increase to more than 50 m2 per person. Obviously, more floor space needs more energy for space heating and cooling, ventilation, and lighting, but it also allows the household to operate more and or bigger appliances, all of which increase energy consumption.
On the other hand, housing projects emerge offering relatively small private living spaces in combination with various shared spaces to use. Many of them are based on private initiatives. But what is the motivation behind it? And is there a higher need for new living concepts in the future?
The proposed paper presents main drivers of increasing floor space per capita in Germany and discusses the question if more space is necessary for higher comfort. It presents different examples of housing concepts that strive to achieve good living with less space and suggests a "building typology of sufficiency".
Finally, the paper discusses qualitatively to which extent these housing concepts can lead to less energy use and emissions. In this way sufficiency could be best friend with efficiency and tackle wealth, rebound, and other effects that counter-act efficiency progress. But therefore, as the paper concludes, politics and policies should recognise sufficiency as a field of action instead of referring to individual decisions and lifestyles.
What are the best policies and measures to stimulate energy efficiency in buildings? The debate around this is at least as diverse as the markets and concepts for energy efficiency in buildings, and often quite controversial. However, no magic formula seems to have been found so far. It is, therefore, time to address the question in a new way - by combining both theoretical evidence on what policy support markets need, and empirical evidence on which combinations or packages of policies have worked.
In the context of its new four-year project bigEE - "Bridging the Information Gap on Energy Efficiency in Buildings", the Wuppertal Institute is implementing this new approach. The bigEE project aims at developing an international internet-based knowledge platform for energy efficiency in buildings. Hence, it must provide evidence-based information. On the theoretical side, the analysis starts with value chains in the building sector and the barriers but also actor-inherent incentives that the different types of market participants face. This enables to identify, which policies and measures need to be combined to jointly overcome the barriers and strengthen the incentives. On the empirical side, model examples of good practice are collected and compared. The search for these is guided by the results of the theoretical analysis, international expert opinion, and existing databases and platforms. In order to identify what is "good practice", the project uses a newly developed multi-criteria assessment scheme. Finally, the impacts achieved with the model examples, lessons learned, and their transferability will be used to validate the model policy package identified in the theoretical analysis.
The public launch of the bigEE platform is planned for autumn of 2011; eceee Summer Study participants will get a first glance at its content through this paper. The paper presents the methods and tools used and showcases their application for the case of new buildings