Richard Harral of the Chartered Association of Building Engineers (CABE) discusses how the ongoing Part L consultation is the clear way forward to genuine carbon reductions, including closing the performance gap.
For all those of us who believe that we are indeed in an emerging climate crisis (and the evidence is compelling to say the least), news that Government has published proposals to improve the energy efficiency of new housing will be most welcome, if long overdue. Improving Energy efficiency for new homes is critical and the new consultation makes it clear that this is still priority number one.
The consultation sets out two key options for introduction in 2020 as a stepping stone to achieving the ‘Future Homes Standard’ by 2025, which will deliver a 75-80 per cent reduction in carbon emissions compared to a Part L 2013-compliant home.
The first option involves a 21 per cent improvement focusing on fabric improvement, and the second a 31 per cent improvement including fabric improvement, PV panels and a switch to low temperature heat (typically heat pumps), with Government setting a clear preference for the latter option. Both are intended to futureproof new homes so that they are capable of easily meeting the full future standard without the need for significant upgrades.
For some this won’t be enough – the debate about the true meaning of zero carbon will no doubt continue (net zero carbon or full zero carbon and whether to include embodied energy expended in construction and across the lifecycle), and the fact that the interim step and the Future Homes Standard both fall short of meeting a full zero carbon metric will be a disappointment.
But these are still significant improvements – the Government’s preferred option from 2020 of a 31 per cent improvement on Part L 2013 (equivalent to around a 40 per cent improvement on Part L 2010) takes all new homes further in energy performance terms than the previous Zero Carbon Standard agreed by the 2010-15 coalition Government (which in broad terms would have seen a 25 per cent improvement on Part L 2013). The Future Homes Standard would then deliver a final step in performance in 2025.
Critically though, restarting the journey to zero carbon needs to be placed in the context of hard-learned lessons from previous pushes on sustainability and take into account the implications of a significant acceleration in renewable generative capacity that is rapidly decarbonising the grid.
We must not forget just how difficult the industry as a whole found the practical journey to achieving genuine Code Level 3 and 4 performance. The Zero Carbon Hub, amongst others, undertook extensive evaluation of the gap between design and actual performance and there is compelling evidence that the shortfall could be much greater than the theoretical benefits delivered by pushing efficiency much harder.
In other words, focusing on industry’s ability to deliver performance is at least as important as setting higher standards. To do so, the consultation suggests more wideranging and important changes than on energy efficiency alone.
One of the main, but often overlooked reasons for such poor performance was that the industry wasn’t just attempting to build new homes to a higher standard, but was in real terms trying to meet six or seven different standards on different sites at the same time. The same sub-contractors would jump from a Part L 2006 site to a Code 6 site, from a Code 3 site to Part L 2010 site, to Part L 2013 and then back to a Code 4 site. In London and elsewhere, further additional uplifts above the applicable Part L standard could be applied through planning policies.
Pushing for higher standards was important and well intentioned, and arguably justified in the absence of central Government pulling out the stops to do more on climate change. But we must learn from the negative impact of the previous fragmented application of standards if we are to achieve the right outcomes in the shortest possible period of time.