How we could use data from meters to show sustainability where Energy Performance Certificates fail
So, we’ve started the third year of a crucial decade in the bid to mitigate the worst effects of climate change. As I write, the government has released its five yearly report outlining the risks posed by climate change. It puts the impact in terms politicians can understand: effect on GDP.
Though ministers say more must be done more quickly, politics does not allow for much long-term thinking. What government would not rather leave their successors to manage a 1% reduction in GDP? Though, of course, climate change is about much more than money.
According to the 2021 Committee on Climate Change report there has been almost none of the necessary progress in upgrading the building stock – second only to surface transport as the largest emitter of CO2 in the UK. In particular, weening our buildings of gas used for heating is a significant challenge, particularly when electricity is a significantly more expensive.
It is encouraging that in my role I have to speak to various organisations that have declared a target of net zero carbon in their estates by 2030. I am often dismayed that Energy Performance Certificates (EPCs) are proposed as a primary indicator of progress. As effectively an extension of the theoretical assessments that underpin the building regulations, EPCs are subject to the performance gap we see between design estimates of energy use and reality.
Research by the Better Buildings Partnership elegantly illustrates that EPCs can in no way be relied on as an indicator of energy bills. The actual performance of a building will be a product of how effective the fabric is, how efficient its systems are and how occupants behave. To make performance improvements, all three of these factors must be understood in real terms.
Atamate advocates a data-driven approach to net zero: basically, organisations need to know how much energy their estate uses in order to record improvements toward net zero. Beyond this, it is important to collect data on energy consumption, environmental conditions and occupancy patterns, the more granular in terms of spaces the better. Analysing these parameters can reveal whether the users are selecting appropriate temperatures, whether systems are performing effectively and, most importantly, whether they respond to occupancy.
The key is for sensor networks to be simple to deploy data to inform actionable insights. Since the update to Part L in 2006 included a requirement for energy sub-metering, many buildings have extensive networks of meters where the data is not being reviewed meaningfully. A starting point is surfacing it to a data platform for analysis.
Government buildings require Display Energy Certificates as well as an EPC. A DEC is based on actual energy usage and is easier to produce than an EPC, though the EPC remains compulsory in the private sector. The government is seeking to address this in large commercial buildings, however, consulting last year on a performance-based policy framework.
But the principle of data-driven decision making en route to net zero applies to buildings of all sizes. Around 60% of energy use in the non-residential sector occurs in buildings under 5,000m², and with extremely high energy prices. Don’t we need more data before deciding how to decarbonise the heating in our homes?
Dan Cash is a building services engineer and director of consulting at Atamate