Outlook for low carbon homes

Policy context

Having set very ambitious targets for zero carbon new homes in 2006, the UK government and the ZCH hub have periodically reduced the scope of the requirements. It seems that to some extent the original definition; which included unregulated emissions, was technically unachievable for many projects (ZCH, 2011) . However it can be argued, that that anticipation of the standard, had been driving significant innovation within the industry. Indeed estimates of a £36,000 additional build cost (Osmani and O’Reilly, 2009), had reduced to under £5,000 per property, by the time of the requirement coming in, in 2016 (ZCH, 2014).

Although various academic surveys with key industry stakeholders, have identified concerns of a capacity and skills gap (Osmani and O’Reilly, 2009, Heffernan et al., 2015), chief among concerns has been an uncertain policy landscape. This makes the recent decision to scrap the ZC standard all the more beguiling. It would seem that many of the technical challenges had been to a large extent overcome, with many key regime actors having invested significant research and development funding, into improving the thermal and carbon performance of mass built, mainstream housing. In this respect, the actions of the ZCH would have seemed to be successful as providing a key intermediation role between industry and government; a key point source for information and expertise in development of the policy.

The current policy landscape is now extremely uncertain for zero carbon new build. The demand drivers from consumers are likely to be limited; given the typically speculative nature of property development in the UK. Furthermore, developers are unable to capture the cost benefits, of reduced energy consumption and microgeneration.

However, self-build models may be a more effective means of overcoming these split incentives. An important area for future research may be to identify the differing drivers and barriers identified by self-build projects, and how this informs the energy and carbon performance design of these homes.

In contrast to new buildings, there have been no major overreaching targets for low and zero carbon retrofit. This is not to say there has been a dearth of policy interventions in this area, with the latest incarnation of the energy efficiency supplier obligation schemes; ECO having delivered measures to over 1,232,068 properties (DECC, 2015a). By contrast the Green Deal; aimed at the able to pay market, has been a spectacular failure, delivering only 9,999 finance plans as of August 2015.

However, neither of these schemes are likely to have delivered significant numbers of what is termed ‘deep’ or ‘whole house’ retrofit. ECO interventions have tended to deliver piecemeal, lowest cost interventions with a large component of cavity wall (532,573) and loft insulation measures (353,244) (DECC, 2015b). Previous schemes such as CERT had also involved subsidised uptake of energy efficient light bulbs, although the CERT initiative will see a lifetime 296.9 Mt of CO2 mitigated (Ofgem, 2013).

It seems fairly clear that given the imperative for lowest cost emissions reductions, in the past SOs, is likely to have had limited impact on solid wall and hard to treat properties. Based on the HEED dataset, it is likely that the remaining solid walls that represent approximately 27% of the existing stock are mostly untreated. These measures represent the single biggest potential for CO2 mitigation from existing buildings, with approx. 9.38Mt CO2 a year available (EST, 2013). It is also estimated that up to 57.4% of houses in the UK still have single glazed windows (HEED, 2015).

The local policy landscape however, paints a more progressive picture of requirements for new, and to a lesser extent existing buildings. Many LAs across the country have requirements for improved CO2 and energy performance, above and beyond what is expected by building regulations. In London, residential buildings have been required to demonstrate a 25% Improvement on 2010 Building Regulations between 2010-2013, and a 40% improvement between 2013-2016 .

This has typically included requirements for meeting CfSH level 3 and subsequently 4 during these periods. It is estimated approximately 55% of LAs in England have required developments to meet standards in the Code for Sustainable Homes and/or BREEAM in their LDF and local plans (BRE, 2015). This has included a significant number, requiring adherence to the BDR framework, mandating an ‘Excellent’ score from 2013 onwards; equivalent to a minimum EPC score of C or above.

However, these standards only become required when property is undergoing ‘major refurbishment’, typically requiring a conversion of 5 or more dwellings or 500m2 of any floor space (Camden, 2015). It would seem then that these policies alone may have limited impact on the domestic stock as a whole; which remains dominated by the small scale private owner occupied and private rented sector.

It seems clear that the past mix of policy measures has indeed promoted a move to the improvement of both the existing and new building stock. However, the majority of interventions for existing building thus far have tended to result in a limited uptake of lowest cost measures, having done little to promote or incentivise holistic, innovative and disruptive solutions. The lack of progress with solid wall insulation and innovative heating systems; such as heat pumps, can be seen as symptomatic of this problem. Indeed, it can be argued that the range of financial instruments and supplier obligations, may have done little to adjust the underlying cause of the poor thermal quality of the UK housing stock. These problems, are characterised by an industry locked in to traditional working practices, a poorly informed and immobile consumer; who often has little agency when making housing choices, and uncertain returns from efficiency investment. It can be argued that significant progress had been made towards zero carbon new build, yet the recent policy announcements, have further contributed, to a widespread perception of an erratic, uncertain and opaque policy landscape.


BRE. 2015. BREEAM: Planning Policy: BREEAM and Code for Sustainable Homes in local plans [Online]. Available: http://www.breeam.org/page.jsp?id=333 [Accessed 10/08/15].

CAMDEN 2015. Camden Planning Guidance 3 Sustainabilty. In: CAMDEN, L. B. O. (ed.). London.

DECC 2015a. Domestic Green Deal and Energy Company Obligation in Great Britain, Monthly report – 20 August 2015. In: CHANGE, D. O. E. A. C. (ed.). London: National Statistics.

DECC 2015b. Domestic Green Deal and Energy Company Obligation in Great Britain, Monthly report: August 2015. London: National Statisitcs.

HEED 2015. Homes Energy Efficiency Database – HEED Online 3 – Installations Summary. Energy Saving Trust.

HEFFERNAN, E., PAN, W., LIANG, X. & DE WILDE, P. 2015. Zero carbon homes: Perceptions from the UK construction industry. Energy Policy, 79, 23-36.

OFGEM 2013. The final report of the Carbon Emissions Reduction Target (CERT) 2008-2012. In: OFGEM (ed.). London.

OSMANI, M. & O’REILLY, A. 2009. Feasibility of zero carbon homes in England by 2016: A house builder’s perspective. Building and Environment, 44, 1917-1924.

ZCH 2011. Carbon compliance: Setting an appropriate limit for zero carbon new homes – Findings and Recommendations. London: Zero Carbon Hub.

ZCH 2014. Cost Analysis – Meeting the Zero Carbon Standard. Zero Carbon Hub.