EPC misses target

“It’s very tempting to think that by simply lowering a figure you can control the energy aspects of newly built housing,” says Professor Henk Visscher (OTB), who lectures on housing quality and process innovation. The reality however is that there are other factors in play, such as building quality and differences between households (which can vary up to a factor of 2).

The much-talked about EPC (energy performance coefficient) reflects the primary, annual energy consumption of a building, divided by a weighed total of floor and wall surfaces. In 1995, the EPC stood at 1.4, but was tightened to 1.2 in 1998. It now stands at 0.8, with a further reduction down to 0.6 coming into effect as of January 2011.

Consequently, one might think that between 1995 and today the energy consumption of buildings has been more than halved, but Dr Olivia Guerra Santín’s research proved otherwise.

Her research was partially based on data derived from two Ministry of Environment (VROM) databases, which taken together produce the Dutch housing stock’s official and representative quality measure. Moreover, she added a questionnaire, which focussed on the residents’ lifestyles.
The results were shocking: according to statistical analysis, only 20 percent of energy consumption variations could be explained by differences in EPC-values, while a whopping 80 percent of energy use variation had nothing at all to do with the EPC. Part of this variation could be explained by taking the various households into account; however, for nearly half the energy variation, there was only one explanation: faulty installation work.
“The government shouldn’t set an EPC value without surveying the outcome,” Prof. Visscher concludes. “Nowadays, the quality of insulation and air-tightness can be easily checked.”

Olivia Guerra Santín, Actual energy consumption in dwellings, 19 October 2010, PhD supervisor Professor Henk Visscher.

Link to article in Delta