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Member Briefing: Government consults on small sites exemption for zero carbon homes

Date: 18/11/14

Government consults on small sites exemption for zero carbon homes

In July 2014, in its response to a consultation on ‘Allowable Solutions: Next Steps to Zero Carbon Homes’, the Government announced that it planned to consult on an exemption for smaller residential sites in England.

The consultation published today provides a justification and explores options for the structure of the exemption which is primarily targeted at reducing the regulatory burden for small house builders.

Defining the exemption in terms of development size or developer size

Whilst recognising that not all developments on small sites are undertaken by smaller developers (particularly in rural areas), the Government proposes that the exemption be defined in terms of the size of site, with a threshold of 10 units or fewer proposed as the trigger for the exemption. The paper does, however, maintain that the exact site size is still to be determined and further evidence to inform future decision on the level is sought.

It is argued that the site size exemption is more easily checkable by Building Control bodies and provides an easily understandable definition for national application. To further target the exemption the Government is considering imposing a total development floor space condition with a figure of 1,000 square metres for a 10 unit scheme (or 100 metres per dwelling) referenced in the paper.

The Government also sets out a possible alternative based on company size. Using the Government’s standard definition of a small company, i.e. one which has fewer than 50 employees. This would prevent larger companies developing small sites from benefiting from the exemption but recognition is given to the fact that the impact of sub-contracting or the role of subsidiaries would be difficult to account for whilst also imposing an additional burden on Building Control bodies.

A third option involving some combination of both site size and developer size could be considered.

Scope of the exemption

The zero carbon standard will comprise two elements: the on-site energy efficiency requirement and the allowable solutions element. Allowable solutions can be off-site carbon abatement, further on-site carbon abatement or a combination thereof.

Smaller sites or developers could be exempted from any requirement to contribute to allowable solutions meaning that while all developments in England would be required to build to a minimum requirement set in Part L of Building Regulations, smaller sites/developers would not have to carry out further abatement measures.

Whilst this approach would mean that all new homes meet the highest levels of energy efficiency, the cost savings for smaller developers would be smaller and could harm the ability of SMEs to compete.

This approach, to exempt small sites from the allowable solutions component only, is the Government’s preferred approach.

The second option is to introduce a two-tier approach to Part L, either through separate regulations or a longer transitional period.  This would result in the creation of dual standards of housing in England in relation to energy efficiency. The Government notes that supply chains would thus have to offer a wider range of products to builders. 

Time frame

The Government intended to review the exemption after a period of five years leaving open the possibility that ‘we may want to consider whether the full requirements of zero carbon homes should be achieved by all homes irrespective of site or developer size’. This is also intended to align with new European requirements which come into effect at the end of 2020. 


Based on 2013 data, the Government estimate that an exemption based on site size would capture just over 20% of new homes granted planning permission in England.

The paper can be read HERE. The consultation closes on 7th January 2015. HBF will be submitting a response and will be seeking members’ input.


David O’Leary

Deputy Director of External Affairs