BOLIG+, measurements, evaluation and dissemination

The concept of BOLIG+ (Living+) was created during Energy Camp 2005 where large parts of the Danish energy and building industry was gathered to discuss energy solutions for the future.

Initially, BOLIG+ was based on five dogmas:

1. Energy neutral in the sense that the building produces the same amount of primary energy as it consumes on annual basis, including the resident’s consumption for light, cooking, entertainment etc.
2. The dwelling must have a good and healthy indoor climate
3. The dwelling must be flexible over time and for different locations
4. The dwelling must be intelligent and user friendly
5. The building must fit into the local energy infrastructure and architecture Following Energy Camp 2005, the BOLIG+ dogmas were refined and a contest for a multifamily house with 70 flats was conducted.

During the development of the rules for the contest, a sixth dogma emerged:

• The building should be constructed on normal economic market conditions. 

The economic crises, starting in 2008, did unfortunately put a hold to the construction of the winning BOLIG+ proposal. It took several year before a BOLIG+ multifamily house was constructed at Søborg in the suburbs of Copenhagen. The building is in a smaller scale, with only 10 flats each having a heated gross floor area between 90 and 140 m².

BOLIG+ at Søborg was the first attempt to construct a multi-family block of flats that complies with a set of criteria and dogmas that defines the concept. Building multi-family houses that are energy neutral on annual basis, is much more difficult than for a single-family house. One of the reasons for this is the small amount of roof area available (per. dwelling) for local electricity production compared to the roof area of a single-family house.

Did the building meet the BOLIG+ dogmas?

The building would almost have been energy neutral, given the photovoltaic system had produced the planned amount of electricity and the residents had used a little less electricity, in accordance with the BOLIG+ requirement of 1725 kWh/dwelling per year.

The building meets the Building class 2020 energy performance requirement as defined in the Danish Building regulations 2010/2015 without contribution from local renewable electricity production. This highlights that the building itself has a very good energy performance, created by utilizing simple and well-known measures. However, the evaluation also highlights that without the resident’s involvement in correct use of the building, it is not possible to meet the target. During winter, there is a good indoor climate in the building in terms of indoor temperature and CO2 level. However, some residents complain about dry air during the heating season, which unfortunately is a natural consequence of having an adequate air-change. During summer, the moisture and CO2 level are satisfactory, but overheating occurs in several of the rooms. The rooms most exposed to overheating are the ones that faces east and thus get a large amount of morning sun. It is expected that the overheating issue could have been reduced by introduction of external solar shading – especially as the natural ventilation proved insufficient to reduce the problem. 

It is possible for the residents to control several systems in their flats; however, an insufficient information level has been an issue for some systems. Especially, information on the ventilation system was insufficient resulting in often-wrong use of the systems. As a contrast, information about the intelligent power outlets and control of these has been sufficient and several residents have customised the programming of the system. The building fits the local energy infrastructure as it is heated by district heating. The building can in the future provide service to the surrounding electricity grid, as it is equipped with a battery (connected to the PV system) that can be charged and discharged according to the amount of electricity from renewables in the grid. Weather the building, with its black and white sections on the facade, fits into the local architecture dominated by red masonry houses is of course a matter of taste, however, it is undiscussable that the building is a landmark at the top of the hill where the building is situated. By utilizing simple and well-known technologies, it has been possible to construct BOLIG+ at Søborg on ordinary economic market conditions.