In her speech last month setting out the government's proposed legislative programme for the year ahead, the Queen confirmed that we will be building zero-carbon homes in 2016. Surprisingly, she also revealed a loophole that could let developers bypass carbon reduction schemes on small sites.
The Zero Carbon Hub (ZCH) has been working with industry and government since 2008 to develop a realistic solution for procuring zero-carbon homes by 2016. In its original incarnation, a zero-carbon home meant exactly that, a home with no net carbon emissions. The definition has since been diluted several times. Currently a zero-carbon home means one with a carbon footprint of about 10kgCO2/m2/a, roughly 1 tonne a year - with the carbon offset using 'allowable solutions' to arrive at the 'zero' rating.
The ZCH describes 'allowable solutions' as 'a cost effective and flexible means to achieve zero carbon, after complying with a set level of on-site requirements'. The easiest method is to pay into a carbon fund which procures carbon offsetting schemes 'selected locally or from a national list of projects'. The drawback is that developers can build homes to a lesser energy standard and compensate with carbon offsetting elsewhere.
Building truly zero-carbon homes, or directly managing investment in a carbon reduction programme within the development, delivers the same net carbon reductions as 'allowable solutions', but with better social and environmental outcomes. This route would deliver a better standard of energy-efficient home, yet the allowable solutions route offers funding for community projects such as district heating, social housing retrofit and local renewable energy, all of which benefit wider society.
The success of allowable solutions lies in the detail. If implemented properly, it could lead to the construction of decent, low-energy homes, plus a new funding mechanism for community energy schemes.
Focusing on the challenges of small schemes, the Queen’s announcement reads: 'Small sites, which are most commonly developed by small-scale housebuilders, will be exempt. The definition of a small site will be consulted on shortly and set out in regulation.' The size of small developments is yet to be defined, but it could be as high as 50 dwellings. This would constitute a significant shift in policy. RIBA president Stephen Hodder is one of many industry critics of the proposal. He suggests it will lead to developers parcelling developments in order to avoid the carbon tax, causing needless delay in production and excessive bureaucracy, as well as a potential two-tier Part L, with different standards for small and large sites.
This exemption of small sites is not necessarily bad. Housebuilders still have to meet carbon compliance, which is currently a reasonable target set just above Code for Sustainable Homes Level4. Full zero carbon is not always technically or financially possible for smaller housebuilders. But, in order to achieve its aims, the government needs to balance this concession to smaller sites with greater standards of fabric efficiency and as-built performance in its next Building Regulations review.
The government is starting to take notice of the need to concentrate on as-built performance. The detail of this new policy must incentivise developers to build genuine low-carbon homes, which perform as designed. One such policy has been adopted in Belgium, where Passivhaus standards will be mandatory in new build and retrofit from January 2015. Belgium started in 2007 with incentives, paying €100/m2 to those building to Passivhaus standard and monitoring as-built performance. This is exactly the sort of policy we need in the UK. We need a radical change in procurement and regulations, resulting in an approach that prioritises tested performance, with or without 'allowable solutions'.