By David Graff, AAU Kommunikation and Public Affairs

The requirements in Denmark and the EU for the energy efficiency of the building stock are tightening more and more, and with good reason – energy consumption for heating, cooling, ventilation, and lighting in our buildings accounts for approx. 20 percent of society's total emissions of greenhouse gasses. However, staying within the requirements seems shorter than one might think for preservation-worthy apartment buildings.

Gentle interventions are usually sufficient

70 percent of the preservation-worthy multi-story dwelling properties – i.e. properties considered preservation-worthy according to the so-called SAVE register – already have energy label D or better. This is fully on par with apartment buildings in general, points out senior researcher Ole Michael Jensen.

"Blocks of flats generally perform surprisingly well, and this is due to three things: They have a large volume in relation to their surface, they stand "shoulder to shoulder", and they are typically located in district heating areas, which often use renewable energy sources," he elaborates

For the remaining 30 percent, re-insulation of the roof and ceiling, replacement of windows and heating systems, or insulation in floor separations will in the by far largest amount of cases be sufficient, explains Ole Michael Jensen:

"It is quite normal that in building cases concerning preservation-worthy buildings, you doubt whether the renovation might harm the conservation value and the architectural expression. But now we clearly show that classic renovation methods go a long way without doing harm," he says.

Exterior renovation can make sense

BUILD's study thus concludes that good energy labels can typically be achieved without external re-insulation. Because as senior researcher Jesper Ole Jensen from BUILD explains:

"There is no reason to believe that the preservation-worthy buildings must be wrapped in insulation material to become energy efficient. It is usually enough with relatively simple measures that do not cost the world or destroy the preservation value of the buildings."

However, energy solutions can also be used that affect the exterior of a building, but which still make sense when an older multi-story residential property needs to be improved to a higher energy class.

These solutions remedy obvious shortcomings or contribute to bringing out a building's architectural qualities in the cityscape. An example can be seen in Mejlgade in Aarhus, where an older apartment building in conservation class 2 has been optimized by putting a completely new upper part on the property. The new upper part highlights the building's distinctive character and harmonizes well architecturally with its surroundings.

The example from Mejlgade can be seen in the film: How can you energy-renovate buildings worthy of preservation? [LINK]

See also: Why energy renovate buildings worthy of preservation? [LINK]