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Low energy retrofitting

On this page you will find lessons learnt that are distilled from various workshops that the SCIS team attended. The most important points are summarised, giving a quick overview of the challenges / barriers but also solutions with regard to each topic.
Low Energy Retrofitting
Lesson identified at: 


Low energy retrofitting is one of the main undertakings of smart city projects. However, to retrofit old buildings, to assure the desired end results in regard to increased comfort and realized energy savings as well as to find a good baseline energy consumption a priori and a good monitoring system a posteriori, can be challenging. Since retrofitting works go hand in hand with rent impairments, various social and behavioural barriers do also have to be tackled. Tenants need to be reallocated, and their approvals for individual metering and post-renovation monitoring have to be obtained. People in charge should seek for citizen engagement and social acceptance: They might come across a lack of environmental awareness or other priorities than retrofitting (e.g. due to age or social/economic vulnerability) among homeowners. In private multi-owner residential buildings, it is also challenging to find an overall agreement on the building which is often caused by some owners lacking financial capabilities. Finding a good finance mix between tenants and public/private and determining retrofitting measures that are eligible for subsidies can also be quite difficult. Moreover, there might be a discrepancy between owners paying the retrofitting investment and tenants paying the energy bills. Another challenge is to come up with solutions for small and medium sized cities, mainly due to their economy scale which is less applicable and their lack of competencies and time. When retrofitting multi-dwelling buildings, it can also be difficult to obtain each tenant’s agreement and to get skilled staff (craftsmen; coordination and supervision of sub-contractors; availability of work permits). Furthermore, “half empty” buildings are not easy to engage in retrofitting and may not be able to enjoy all the benefits. Regulatory wise, building permits as well as cultural heritage, the prohibition to transfer electricity between buildings (e.g. in Finland, Spain, Sweden), monitoring without breaking the data protection law, and the fact that cities cannot have more ambitious demands for buildings than opposed by national legislation (unless the city owns the land or makes use of an exploitation contract) might be causing problems. This does also apply to geographical differences that may limit the easiness of replication.        


The adjustment of regulations to facilitate permitting for energy retrofitting, the promotion of energy exchange from a regulatory perspective as well as the application of regulations related to building properties on the building level and applying energy supply regulations on a community level are distinct policy recommendations. To measure the increase in comfort, to intensify the engagement with private owners, especially when working in a multi ownership context, and to facilitate loans for the whole operation to cover investment costs and to avoid tenants having to make the investment are considered as user incentives. Best practices and suggestions are multitudinously: To include the energy performance in procurement and to specify the expected energetic and comfort performance in tenders and contracts, to assure that monitoring data is available (municipalities should use it to create good business models) as well as to involve public services in district heating infrastructure to increase confidence with other stakeholders are among them. It should also be kept in mind that the business model for retrofitting is best when the building’s lifetime is ending.  It is also recommended to increase ROI by incorporating PV installations or combining several forms of retrofitting (e.g. energy and structural retrofitting). One should also consider financing by ESCO’s, collective funding or a combination (e.g. public private partnership). Tenants should not have to make the complete investment. It is also a matter of fact that buildings owned by a single entity (e.g. company) are easier to target. It is furthermore advisable to make use of demand response and weather forecast to manage energy performance of buildings and apply smart metering. Moreover, individual thermal control and energy measurement (at building level) should be implemented. It is also highly recommended to make use of IOT devices and real data monitoring as well as choosing the building one wants to retrofit carefully, considering several factors (building ownership, legal context, etc.) to increase the project’s chance of success. Applying a district thinking approach for renovation and new construction can also be beneficial. This could increase the applicability of the ESCO model. Targeting a mixed building portfolio (residential and tertiary) or big facilities could also be beneficial for the business case (higher flexibility, economy of scale). When focussing on similar buildings, tailor-made solutions can be applied to them. It is also beneficial to incorporate good communication from the early start of the project. Finally, the organisation of workshops (e.g. for housing corporations) to show the benefits of renovations is useful.

Plan for Implementation 

To reach the national government, local authorities in Denmark are combining efforts to have a stronger voice and as such reach change and affect policies. Persons in charge can integrate other partners in retrofitting projects and aim for a single holistic project instead of several smaller ones. They can also create a strategy campaign to promote the benefits of retrofitting (energy savings, better quality of living, etc.) to convince and gain trusts from tenants. It can also be considered as mandatory to provide clarification on the ownership of the data resulting from monitoring. At a city level, more efforts can be put in advising private house/apartment owners and in spreading knowledge. Scaling up the retrofitting in public office buildings and exploring the possibilities of a revolving fund can also be considered as next steps. Last but not least, taking part in replication workshops with follower cities as well as discussing the district approach and sharing results with other housing associations can be reasonable.