When buying a home, it is good practice to check its utility bills and energy label. In 2010, energy performance of a home was however not yet a strong determinant of price except possibly in some extreme cases.
This made sense since a typical purchase price of a home today may be 250 times its annual energy bill. That’s why our mortgage payments are so much higher than our utility bills.
This situation changed over the past years . Nowadays, few buyers will omit to ask for past utility bills, and a poor energy performance will reflect badly on the value of a property.
The term ‘zero energy’ sounds contradictory. We need energy to produce materials, then construct, operate and renovate or demolish buildings. Once a building is occupied, we need energy for heating, cooling, hot water, cooking, and we use electricity for a myriad of other energy services. And there is a temporal dimension – to produce energy at the time when it is needed.
‘Zero energy’ in its current use does not mean ‘compensating all energy uses related to the building, over its entire lifecycle, at the time when energy is needed’.
The term works well as a commercial label. For regulation, it lacks precision.
LEED and other certification have been driven a shift towards more energy efficient buildings. Yet, most buildings don’t perform as well as was anticipated at the design stage – deviations of 2 to 5 times the predicted energy use are reported. Poorly controlled installations and ‘bad’ user behaviour are to be blamed. Certification based on tracked actual building performance is what we need not to fall short in reducing emissions. The good news: regulations increasingly adopt incentives for smart metering, automation and control functionalities, while establishing legal frameworks to help the general public embrace digitization and (big) data evolutions.