Why It’s Time to Think About Operational Carbon in Housebuilding
The carbon zero agenda for housing has three main elements: embodied carbon, operational carbon and avoidable carbon associated with waste. This is why the issue needs a holistic approach. Housebuilding must address all three aspects. And it all starts with the building fabric and construction methods.
At first sight, fabric-first and MMC-based approaches would seem to be targeted at embodied carbon. They certainly have a major impact in this area. Using structural timber with negative embodied carbon in place of cement and steel is bound to make a difference.
But the reality is that, as a nation, we’re still building too many homes that will emit significant levels of greenhouse gases during service. These emissions are likely to dwarf any savings in embodied carbon. There’s already a huge (and unquantified) task to bring our housing stock up to EPC level C, never mind carbon zero. It makes sense not to add to this upgrade mountain.
Who Bears The Cost?
Until recently, a big issue was one of timing and apportioning cost. The additional cost of energy efficiency could be incurred during construction or later on. And any added energy costs would be passed on to the occupier in the meantime.
That approach is redundant. Not only because it doesn’t get us anywhere but also because it’s not a choice that has to be made.
We know how to build energy-efficient homes using MMC. We also know that energy efficiency levels can be guaranteed so that zero operational carbon can be a reality deployed at scale.
Modern construction methods bring the opportunity to deliver cost savings through standardised products and repeatable processes. When combined with the ability to bring forward completion dates and rental or sales income, and reduced maintenance costs because of improved build quality, the business case becomes even more solid.
The need to address operational carbon during the design and construction phases is urgent. Apart from anything else it will help lift people out of fuel poverty. Hopefully the MMC Task Force announced in the budget will accelerate change.