Buildings are responsible for around half of the UK's greenhouse gas emissions. The building regulations are a key policy measure to address the issue.
Since then, the Government has promised a "step change" in energy efficiency in its 2003 energy White Paper (ENDS Report 338, pp 26-32 ). The recent up energy efficiency implementation plan proposed that improvements to building regulations from 2005 would reduce annual emissions by 0.8mtC (million tonnes of carbon) by 2010, dominated by a 0.69mtC contribution from condensing boilers (ENDS Report 352, pp 45-46 ).
The consultation released in late July offers different numbers. Overall, changes to building regulations are now expected to achieve a saving of 1mtC per year "at the least" by 2010 (see table). The Office for the Deputy Prime Minister says the regulations will deliver energy efficiency improvements of around 25% for dwellings and 27% for other buildings, compared to current standards.
The contribution from condensing boilers has fallen to just over 0.5mtC - apparently reflecting changes to the way that carbon savings are calculated and uncertainties about how many properties will exempt from the requirement to install them.
The Government is also using the revision of the regulations to implement part of the energy performance of buildings Directive which must be transcribed into UK law by 4 January 2005 (ENDS Report 336, p 51 ).
Under the Directive, each new building will have to meet a CO2 emission performance standard - calculated from its floor area, shape, lighting factor and chosen heating fuel. While developers have a high degree of flexibility in how to meet the standard, the regulations also set minimum "U-values" for the thermal permeability of walls, floors, roofs windows and doors.
The Directive's provisions on the energy certification of houses offered for sale will be transposed through the Housing Bill currently before Parliament (ENDS Report 339, p 40 ). Other sections regarding sales and letting of buildings will be implemented through "as yet unspecified instruments".
The ODPM hopes that building regulations for dwellings will be better enforced than at present. Developers will have to pressure test either two units of each building type or 5% of each building type - whichever is the greater.
Pressure testing demonstrates whether buildings meet design specifications in practice, but it is currently not compulsory for homes. A recent study for the ODPM found that as few as 30% of new homes built actually met the current standards.
Developers will also have to avoid solar overheating. They can do this through a combination of window size and orientation, shading and night ventilation.
The consultation received a warm welcome from the energy efficiency lobby. "We cannot stress enough the significance of this document," said Philip Sellwood, chief executive of the Energy Saving Trust. "EST has been calling on Government to bring building regulations in line with EST's Best Practice standards, and these proposals do just that."
Andrew Warren of the Association for the Conservation of Energy also welcomed the draft as "a very positive step forward" which begins to narrow the gap between British standards and those elsewhere in Europe.
However, Mr Warren was disappointed that the draft regulations only require energy labels to be displayed in buildings owned by public sector organisations. The Directive's wording of "institutions providing public services" could have been interpreted to include buildings like banks and hotels, Mr Warren said.
The consultation also says that building-integrated renewables and cutting-edge energy efficient technologies like micro-CHP "can make substantial and cost-effective contributions" to reducing carbon emissions (ENDS Report 353, pp 15-16 ). Such technologies should be incorporated into buildings "where technically, environmentally and economically feasible" - the same wording as in the Directive.
However, the ODPM shies away from setting a mandatory target for these technologies. Instead it expects that they should deliver around 40% of the savings.
In practice, however, the regulations will only significantly boost renewables if the performance standards are set at a sufficiently ambitious level. Then renewables would be competing with more costly energy efficiency measures than are commonly used today. Speaking on behalf of the Renewable Power Association, Jeremy Leggett of Solar Century said the draft changes were "a small step forward rather than the big leap we were hoping for".