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Clean Air Act and Renewable Heat Incentive

The Clean Air Act aims to reduce pollution from smoke, grit and dust.  The Renewable Heat Incentive encourages the use of boilers burning wood and other biomass fuels.

We are in the process of:

  • reviewing the whole of the Clean Air Act
  • streamlining the way appliances and fuels are approved for use in smoke control areas
  • specifying emission limits as a criterion for approval of boilers under the Renewable Heat Incentive.

Review of the Clean Air Act

The Clean Air Act is over 50 years old.  In April 2012 Defra began a comprehensive review of the Act in accordance with commitments under the Red Tape Challenge.


We are currently consulting with stakeholders over broad options for change and improvement and aim to commence the formal consultation process in summer 2013, followed by a second public consultation containing detailed proposals in 2014.

What changes can be expected?

Defra produced an initial scoping paper  in March 2012. Further information will be posted on this site as the review progresses.

Background – what the Clean Air Act does

The Clean Air Act 1993 has its origins in Acts of 1956 and 1968.  In particular, it

  • prohibits emissions of smoke within smoke control areas, unless using an exempted appliance or an authorised fuel  – see for details
  • prohibits emissions of dark smoke from any chimney, or from industrial or trade premises, subject to certain exemptions
  • requires approval of many commercial furnaces to ensure they don’t emit too much smoke, grit and dust
  • requires approval of many furnace chimneys to ensure they are high enough to disperse any residual emissions
  • prohibits cable burning except under an environmental permit.

Report commissioned by Defra to assess the impacts of changes to the Clean Air Act.   This report considers the consequences of repealing or amending the Clean Air Act 1993.   The report was commissioned by Defra under the Governments Red Tape Challenge review of legislation. 

Streamlining the procedures for exempting appliances and authorising fuels

We plan to revise the procedures for getting approval for exempt appliances and authorised fuels.  Our aim is to reduce the burdens on business, and to speed up the approval process.

Until any changes are made the existing procedures and legislation apply.  No changes will be made without consultation.

When will the changes take effect?

We originally planned to have the new system in place by April 2013 however in developing the policy we have identified some issues which require further consideration and we are working with stakeholders and specialists to address.  No changes to the current system will be made without prior consultation.

What is the system we are proposing?

The standards that apply under the new system will be set out in the new regulations and will basically be the same as used by AEA now.

However, instead of listing each fireplace and fuel in Regulations or an Order, we plan to enable suitably qualified test houses to certify compliance with the standards. We intend that such ‘self-certifications’ will be used instead of having to obtain Defra approval via AEA.

Renewable Heat Incentive

In future, eligibility for payment under the Renewable Heat Incentive will be dependent on biomass boilers being able to keep their emissions below certain levels.

The Government’s aim is that by 2020, 12% of heating should come from renewable sources.

The Government’s Renewable Heat Incentive (RHI) scheme gives a financial incentive for biomass boilers, among other renewable energy production technologies, and should help drive a significant increase in the level of renewable heat.

Defra worked with DECC, Ofgem and industry to publish a paper in August 2011 which sets out the mechanism for ensuring that Renewable Heat Incentive financial support is only given to biomass boilers capable of complying with limits of 30g/GJ (particulate matter) and 150g/GJ (oxides of nitrogen).

These limits were included in a DECC consultation issued in September 2012 and will form part of the RHI scheme regulations as of September 2013.  


DECC launched the RHI in November 2011 with a scheme for the non-domestic sector that provides payments to industry, businesses and public sector organisations.  They have now set out plans for providing longer term support for homeowners in ‘Renewable Heat Incentive: the first step to transforming the way we heat our homes’. 

DECC plan to open the household scheme in spring 2014, but in the meantime domestic customers should read our guide on the Renewable Heat Premium Payment scheme for details of the householder voucher scheme that is currently available. The RHPP scheme has been extended for a further year to March 2014 to provide continued support for households until the domestic RHI is introduced.

More information on the RHI can be found on the DECC pages of the GOV.UK website

What will the changes be?

The limits of 30g/GJ particulate matter and 150g/GJ oxides of nitrogen expressed as nitrogen dioxide will become included in the criteria for RHI support. These requirements will come in to force as part of the RHI accreditation process as of 24 September 2013.

Frequently asked questions produced by Ofgem are available for those intending to apply for the Renewable Heat Incentive.

Contact us

For any queries about the Clean Air Act or the air pollution aspects of the Renewable Heat Incentive, please email


7 June 2012

Page last modified: 9 August 2013