Method for planning extensive energy renovation of detached single-family houses

Abstract

It has long been a political aim to reduce the emissions caused by energy consumption, and in Denmark politicians aim to make Denmark a society independent of fossil fuels by 2050. To achieve this, it is necessary to increase sustainable energy production and reduce energy consumption. This will take time, so both areas must be considered already now, but it will be beneficial to work on reducing the consumption before the sustainable energy supply is fully developed, so that we can avoid expensive over-production. Some 30% of the total energy consumption in Denmark takes place in households, and 22% occurs in single-family houses, making this the largest single contributor to the total consumption after road transport (DEA, 2015a). There is a large potential for achieving energy savings in this sector, especially among the large number of single-family houses built in the 1960s and 1970s. Many of these were built before the introduction of actual regulations for energy consumption in buildings, and many will soon need considerable renovation due to their age. However, despite the potential for achieving savings and updating these houses built about 40-60 years ago, the renovation of the building stock is proceeding very slowly. This is partly due to problems with the process, in which the initiative rests very much with the house owners, and partly due to barriers to renovation that are currently unaddressed by policy makers. One of the problems addressed in this thesis is the process. In the hope that this could be improved, the use of a One-Stop-Shop (OSS) was investigated and tested. With an OSS, one contact person guides the house owners through all five phases of renovation: initial planning, thorough analysis, deciding on specific solutions, implementation, and verification through measurements. Although the case study suffered from a very high dropout rate, one renovation was successfully completed, and a second followed the project until the start of the fourth phase. While the study did not find evidence that the use of an OSS concept would motivate people to renovate, it did find that the use of this approach produced a better renovation with a larger energy saving. The initial evaluation helped the house owners identify a maintenance backlog, and the use of an independent advisor helped ensure quality throughout the process. Renovations are too often carried out for just one purpose: maintenance, to update functions or to reduce energy consumption. But a lot can be gained by combining these efforts, which can reduce expenses for planning and execution and avoid doing things twice. Research for this thesis demonstrated this approach by carrying out a renovation based on maintenance, but including the owners’ wishes for functional improvements and better than mandatory energy improvements. The renovation resulted in increased comfort, a reduction of 53% for heating, and an increase in the value of the house corresponding to 77% of the investment. There are a lot of barriers that discourage people from embarking on a renovation, and one way to deal with these barriers is through targeted policy. The research created an overview of current policy in this field in Denmark and compared it with the known barriers and motivations, which were collected in a framework to make it possible to identify the areas where current policy falls short. Four points in need of improvement and attention were identified: focus, finance, plans and regulation. The focus must be moved to improving comfort instead of energy renovation as an investment, because this is doing the field a serious disservice. There is a need for more financial support in the form of cheap loans and non-symbolic subsidies, which can overcome the barrier of lack of finance and motivate more extensive renovations. House owners should receive long-term renovation plans for their house, which inform them of their maintenance backlog and inspire energy improvements. And finally, it will be necessary to use regulation to reach those who are not planning to renovate. This could be done for example by setting a maximum allowed energy consumption per m2 in houses, though this would have to be backed up by subsidies to avoid creating major social imbalance.