Barriers to Low and Zero carbon homes
The following section highlights some of the key barriers to the diffusion of LZC new build and retrofit in the UK. Although many of the issues are fairly consistent between both new build and retrofit, where innovation and adoption faces simmilar barriers, there are a number of areas where the challenges diverge. These barrieres are associated with concerns over the economic benefits, technical challenges and shortfalls and the cultural and behaviour attitudes that may inhibit the transition to a predomiantly low energy building regime.
The following section will provide a brief summary of some of the key barriers and challenges that are associated with the diffusion and adoption of new low and zero carbon housing, with reference to the current policy landscape. Whilst many of the methods and technological solutions adopted are similar in both the new build and retrofit contexts, some of the modes and methods of delivery along with the associated incentive schemes and government interventions differ considerably.
Quality, skills and performance issues
A consistently identified barrier to the progress of innovations in the low carbon housing industry is the lack of skills and knowledge in relation to novel technologies and methods (Heffernan et al., 2015, Osmani and O’Reilly, 2009, ZCH, 2013, ZCH, 2014), However Osmani and O’Reilly (2009) describe how in comparison to other barriers, house builders do not see the technical and design challenges themselves as significant barriers to the delivery of zero carbon homes.
An important and related dimension is the performance. Although performance gap issues are typically considered to be more prevalent in a retrofit scenario; given that these interventions tend to be more challenging, it is also considered to be a major issue in new buildings. The Zero Carbon Hub, have commissioned several reports on the issue (ZCH, 2014, ZCH, 2013), the reports cite several key areas for improvement and ‘upskilling’ within the industry:
Improving Quality Output (installation quality)
Demonstrating Performance (real world monitoring/testing)
National Compliance Method and Regime (SAP)
Continued Evidence Gathering
A number of technologies that are seen as key features in a low carbon housing system, such as MVHR and heat pump systems, have in recent times suffered from both perceived and real problems with their operation.
Osmani and O’Reilly (2009) describe how the home warranty provider NHBC when interviewed described being “concerned about micro-renewables being bolted on following several instances where damage has occurred after their installation”.
Air tight construction is a key component of energy conservation, and increasing airtightness to the levels needed to meet both the ZC and Passivhaus standards, is necessitating the use of active ventilation and MVHR systems. Without these systems, internal air quality may suffer from humidity, CO2 and odour issues, and thus not allow for sufficient air changes to meet Part F of building regulations.
However Tweed (2009) describes how anecdotal evidence suggests occupants do not always accept or understand MVHR technology; which is designed to run 24/7 and remove the need for window opening for ventilation .“Occupants have been known to switch off ‘unnecessary’ fans and block air vents’’. These issues are often considered to be systematic of a poor handover and communication of the technology between the builder, client and or tenant. These issues may lead into a situation where adopters of these technologies wrongly perceive them to be unreliable;
‘‘One of the primary issues with the construction of zero carbon homes is the integration of renewable technologies into small scale developments, as it is widely perceived that such technologies are currently unreliable’’ (Osmani and O’Reilly, 2009)
HEFFERNAN, E., PAN, W., LIANG, X. & DE WILDE, P. 2015. Zero carbon homes: Perceptions from the UK construction industry. Energy Policy, 79, 23-36.
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.
TWEED, C. 2009. Occupant interactions with low energy architecture: exploring usability issues. BRE Centre for Sustainable Design of the Built Environment (SuDoBE).
ZCH 2013. Closing the gap between design and as-built performance, New Homes, Interim Progress Report. London: Zero Carbn Hub.
ZCH 2014. Summary: The performance gap – end of term report. Closing the Gap between Design and As-Built Performance. London: Zero Carbn Hub.