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Low energy retrofitting

Low Energy Retrofitting

Challenges/ Barriers facing


  • Retrofitting very old buildings
  • Assuring desired end results with regard to increased comfort and realized energy savings
  • Finding a good baseline energy consumption a priori and a good monitoring system a posteriori

Social & behavioural

  • Reallocation of tenants during the retrofitting works
  • Obtaining tenant’s approval for individual metering and post-renovation monitoring
  • Citizen engagement & social acceptance: lacking environmental awareness among homeowners; other priorities than retrofitting (because of age, social/economic vulnerability; etc.)
  • In private multi-owner residential buildings it is challenging to find an overall agreement on the building retrofitting, often caused by some owners lacking the financial capabilities to retrofit.

Finance & business model

  • Finding a good finance mix (tenant, public/private)
  • Discrepancy between owner paying the retrofitting investment and tenant paying the energy bills
  • Determining retrofitting measures that are eligible for subsidies
  • Coming up with solutions for small & medium sized cities, mainly due to economy of scale which is less applicable and lack of competencies/time within smaller communities

Competences & risks

  • Obtaining each tenant’s agreement when retrofitting multi-dwelling buildings
  • “Half empty” buildings are difficult to engage in retrofitting and may not be able to enjoy all the benefits
  • Availability of skilled staff (craftsmen; coordination & supervision of sub-contractors; availability of work permits)

Regulatory & juridical

  • Building permits; cultural heritage; etc.
  • Prohibition to transfer electricity between buildings (e.g. in Finland, Spain, Sweden)
  • Monitoring without breaking data protection law
  • 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)


  • Geographical differences limit easiness of replication

Incentives/ Policy recommendations/ Suggestions/ Best Practices

Policy recommendations

  • Adjust regulation to facilitate permitting for energy retrofitting
  • Promote energy exchange from a regulatory perspective
  • Apply regulations related to building properties on the building level, apply energy supply regulations on a community level

User incentives

  • Measure the increase in comfort
  • Intensify engagement with private owners, especially when working in a multi ownership context
  • Facilitate loans for the whole operation to cover investment costs and avoid tenants having to make the investment in one go themselves

Best practices & suggestions

  • Include energy performance in procurement & specify the expected energetic and comfort performance in tenders and contracts
  • Monitoring data is available – municipalities should use it to create good business models
  • Public service should be involved in district heating infrastructure to increase confidence with other stakeholders
  • Business model for retrofitting is best when building lifetime is ending
  • Increase ROI by incorporating PV installations or combining several forms of retrofitting (e.g. energy & structural retrofitting)
  • Consider financing by ESCO’s, collective funding, municipal funding or a combination (e.g. public private partnership). Avoid tenants having to make the complete investment.
  • Buildings owned by a single entity (e.g. company) are easier to target
  • Make use of demand response and weather forecast to manage energy performance of buildings
  • Apply smart metering
  • Implement individual thermal control and energy measurement
  • Implement energy measurement at building level
  • Make use of IOT devices and real data monitoring
  • Choose carefully the building you want to retrofit, taking into account several factors (building ownership, legal context, etc.) to increase the project’s chance of success
  • Apply a district thinking approach both for renovation and new construction. This could increase the applicability of the ESCO model. Targeting a mixed building portfolio (residential and tertiary) or big facilities could be beneficial for your business case (higher flexibility, economy of scale).
  • When focussing on similar buildings tailor-made solutions can be applied to them
  • Incorporate good communication from the early start of the project
  • Organise workshops (e.g. for housing corporations) to show the benefits of renovation

Plan for Implementation (Next Steps)

  • To reach national government, local authorities in Denmark are combining efforts to have a stronger voice and as such reach change and affect policies
  • Integrate other partners in retrofitting projects and aim for a single holistic project instead of several smaller ones
  • Create a strategy campaign to promote the benefits of retrofitting (energy savings, better quality of living, etc.) to convince and gain trust from tenants
  • Provide clarification on the ownership of the data resulting from monitoring
  • At city level more efforts will be put in advising private house/apartment owners
  • Scale up retrofitting in public office buildings
  • Spread knowledge
  • Take part in replication workshops with follower cities
  • Set up workshops to discuss the district approach and share results with other housing associations
  • Explore the possibilities of a revolving fund
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