Zero Carbon Definition for Homes – Carbon Compliance Levels Recommended

Thursday, December 16, 2010

A Task Group convened by the Zero Carbon Hub has delivered a report to the Minister for Housing and Local Government setting out its recommendations for carbon compliance levels for new homes from 2016. Carbon Compliance – that is, on-site reductions in emissions – form part of the Government’s overall plan for achieving zero carbon homes; the other part comprises off-site “allowable solutions.”

The Task Group has submitted recommendations to Government about how to make the next steps in achieving zero carbon as effective as possible whilst being compatible with delivery of the full range of housing required.

Separate compliance limits are recommended for detached houses, other houses and low rise apartments. The Task Group has found that the proposal from July 2009, to tighten the carbon compliance standard from 2016 by 70% (equivalent to 6 kg CO2(eq) /m2/year), may not be achievable in all cases.

The recommendations are that the “built performance” emissions from new homes should not exceed:

·         10 kg CO2 /m2/year for detached houses

·         11 kg CO2 /m2/year for other houses

·         14 kg CO2 /m2/year for low rise apartment blocks[1]

A key element of the Group’s recommendations is to ensure that the potential gap between “as designed” and “as built” standards is closed. For this reason the recommendations cannot be directly compared with current standards.

The recommendations are based on detailed modelling of technical feasibilities. They take account of cost and also reflect a wide range of other factors.

The Task Group also recommends an option for carbon compliance to be assessed across the whole of a development site, instead of the individual dwellings on the site.

In its report the Task Group notes areas for further work to be addressed in its final report, due early in the New Year. These include carbon compliance for high rise apartments, sensitivity to the price of allowable solutions, whether regional weather should be reflected in carbon compliance, and the implications for localism.

The Task Group drew its members from 25 groups in the house building and building supply industries, the professions, consumer and environmental groups, and a range of others. The report and its recommendations represent the consensus view of the Task Group (see note 6).

The Group was convened by the Zero Carbon Hub in response to an invitation by the Minister for Housing and Local Government in August 2010 to consider appropriate carbon compliance levels from 2016.

John Slaughter, Director, External Affairs, Home Builders Federation said:

"The Hub has undertaken a difficult and complex task very thoroughly - involving all the key parties in assembling the evidence base for its recommendations on performance standards. These will be challenging for the industry to implement, but we are confident that the Hub's ability to work through tough issues will provide a basis for the industry to resolve any concerns it may discover"

Colin Butfield, Head of Campaigns at WWF-UK, said:

“WWF supports the recommendations, as set out by the Task Group. Whilst we recognise the steps that housebuilders have already made, we feel these standards are the minimum that can still give us the chance of homes we can genuinely call zero carbon. The UK’s climate targets mean there is no slack in the system, and no other sector that can pick up the shortfall if we don’t get this right. It’s not enough just to have 'more efficient' homes, they need to be worthy of the title 'zero carbon'.”

“It's very good news that these standards will be based on how the houses actually perform rather than how they are theoretically designed. Often, in reality, energy efficiency measures do not perform as well as they appear on paper, so it’s to the Task Group's great credit that it hasn’t hidden behind the easy option and promised grand targets but based them on theoretical performance.”

David Adams, Director, Zero Carbon Hub and Task Group Chair said:

“It is critical that the industry has a workable definition for zero carbon homes as soon as possible and this proposal to the Minister is an important step forward. I am very pleased with how well the Task Group worked, there is genuine desire to get this right.”

The interim Task Group report is available from the Zero Carbon Hub website ­­­­


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Notes to Editors

1. The Carbon Compliance Standards apply to built performance where as the 2006 Regulations relate to designed performance. For this reason the recommendations cannot be directly compared with the current standards. However, in addition to any improvement achieved by moving from designed to built performance, the % improvements on the 2006 standard would be:

·         60% for detached houses

·         56% for other houses

·         44% for low rise apartment blocks

2. The Zero Carbon Hub Task Group on Carbon Compliance for Tomorrow’s New Homes found that setting carbon compliance standards as a percentage improvement over a previous standard is increasingly difficult to understand and at risk of causing perverse outcomes. This report, accordingly, refers to carbon compliance in terms of an absolute limit on the predicted emissions of carbon dioxide (or equivalents in other greenhouse gases) per square metre of internal floor space.

3. Carbon compliance represents the overall contribution to achieving zero carbon which can be attained on-site – combining good building fabric performance and use of on-site low and zero carbon energy solutions such as PV and connected heat (community heating networks) to reduce emissions.

4. Carbon compliance measures represent only part of the proposed regime to achieve zero carbon new homes. The Government has recognised that it is not practical to achieve a fully zero carbon new home through on-site measures alone, and has proposed a scheme of “allowable solutions” whereby developers contribute to the cost of off-site measures to mitigate carbon dioxide emissions. The parameters of this scheme have not yet been published.

5. The Task Group’s recommendations are based on a projection of the carbon emission factors that will apply for 2016. They are not the same as the factors used in the current version of SAP, which would give different results. The recommended levels will need to be rebased in due course when the carbon compliance tool for 2016, using the correct 2016 carbon emission factors, is available.

6. The Home Builders Federation (HBF), whose members represent approximately 80% of Housing output, support the recommendations of the Task Group. The House Builders Association (HBA) also on the Task Group, who represents 600 small and medium sized housebuilders, has subsequently stated that it cannot support the level recommended for attached and detached houses.

[1] The unit of measurement is kilograms of carbon dioxide (or equivalent greenhouse gases) per square metre of internal floor space per year.