Waste watching

If the suggestions are adopted, the repercussions for buildings will be immense. The drive for the efficient use of energy will have an unprecedented effect on the way buildings are designed, built and run. It will affect everybody, from those who design and construct buildings to those who occupy and operate them. And the proposals are aimed at new and existing buildings.

Proposals in the new document include the introduction of building logbooks and extensive energy metering in buildings; new measures to improve the efficiency of air-conditioning and lighting systems; and provisions to reduce the amount of air leakage through a building's fabric. The document also proposes an increase in the insulation value of walls, roofs and windows; it even suggests measures to limit a buildings' overheating from solar gain.

The changes are proposed in the consultation document Proposals for Amending the Energy Efficiency Regulations. They will affect both the Building Regulations and the guidance published as Approved Document L, which shows ways of meeting the technical requirements. The regulations will be introduced in stages, with the first coming on stream early in 2002. The regulations will then be tightened through revisions in 2003 and 2005. However, the regulations apply only to England and Wales; Scotland and Northern Ireland will issue their own proposals.

The revisions are aimed at cutting carbon dioxide emissions from buildings – part of the government's larger commitment to achieve a national reduction of CO2 to 20% below 1990 levels. Buildings produce about half of the total of all national CO2 emissions and, on the face of it, are an obvious target for government action. When launching the consultation document, DETR minister Nick Raynsford said: 'Average building performance is poor by comparison with best practice.' These proposals are a move by government to tighten standards of construction.

However, some people feel that the proposals are not sufficiently radical if the problem of global warming is to be seriously addressed. 'The government has not set really rigorous standards,' says Ant Wilson of consultant Oscar Faber.

Andrew Warren, director of the Association for the Conservation of Energy, goes further. 'However apparently radical this document appears, within the context of the threat of climate change it is still opting out of addressing the issue,' he says.

For construction, improving building's energy efficiency could prove expensive. The government predicts that adopting the proposals will cost house builders an extra £1,400 on a semi-detached home, while for commercial developments the figure could be as high as £10/m2 for naturally ventilated buildings and £4.8/m2 for air-conditioned buildings.

The effect of the changes

All new buildings will have to be better insulated. The document calls for 'a significant increase in the insulating performance standards for building fabric'. So the walls, floors, roof and windows of all buildings will have to be more insulated, or be constructed from materials with better insulation properties.

The proposed increases are so high that the DETR has chosen to implement the changes in three phases. The U-values called for in the first phase will be achievable by using current products, the second phase will be much more difficult to achieve and will require changes to wall, roof and window construction, while the third phase will call for a significant rethink in the way buildings are constructed (see panel for figures proposed).

'The changes will be a challenge to both industry and product manufacturers,' said a DETR spokesman. To ensure the insulation performs effectively, the changes propose increasing the standards of detail design and site workmanship to reduce the incidence of gaps in insulation.

Having increased the thermal performance standards of the building fabric, the regulations then address the heat loss through unwanted ventilation. The aim is to improve air-tightness by improving the way buildings are constructed. Designers will have to adopt design details that are acknowledged to work or have to submit a building to a fan pressure test to measure the air leakage directly. For large buildings a mandatory pressure test is proposed.

Average building performance is poor by comparison with best practice

Nick Raynsford

A fundamental change to the regulations is the definition of what is meant by 'building work'. By widening what is meant by 'material alteration' the government has managed to bring work on existing buildings within them. At the moment this will only extend to replacement windows and boilers. These will now have to comply with the new regulations rather than just replacing like with like.

English Heritage in particular is concerned with the impact this will have on listed buildings since replacement wooden sash windows and replacement metal windows will no longer comply with the proposals. 'It's very bad news. These are special buildings and they will be wrecked if these changes go ahead,' says John Fiddler, head of conservation at English Heritage.

The days of the huge glass office block could also be numbered. The changes in the regulations aim to reduce unwanted solar gain by 'the appropriate sizing and orientation of windows, and shading measures'. They also intend to limit internal temperature by using the thermal mass of the structure to absorb excess heat in daytime and release it at night. In order to comply, designers will have to show, by calculation, that internal temperatures will not be excessive.

And if designers are looking to keep temperatures down by introducing air-conditioning, the government has that option covered too. 'Heating, ventilation and air-conditioning are included in the regulations for the first time,' says Ant Wilson. Designers will have to justify the use of air-conditioning using performance standards, but as long as it is not installed to offset the poor performance of building envelope then it will be allowed.

The proposals call for performance standards for all buildings with more than 200m2 of floor area that are air-conditioned or mechanically ventilated.

To comply with the regulations, designers will have to use a new method of calculation called a Carbon Performance Index. This will allow the efficiency of the ventilation system to be assessed and, states the document, it 'will eliminate a significant proportion of office practice that currently falls short of good practice'.

Other changes to the regulations affecting building services include the proposal to introduce requirements for the commissioning of heating, hot water, ventilation, air-conditioning and lighting to ensure the systems work as they were designed. The onus will be on installers to certify they have commissioned the systems to the appropriate standards. Installers will then be required to provide information to occupiers on how to operate their services efficiently.

The job of the commissioning engineer will be made easier by the new requirement to install meters to monitor energy consumption. These will also provide facilities managers with the means to monitor the performance of, say, the heating, lighting or air-conditioning systems during use and compare these with national benchmarks.

To aid this comparison, it is proposed that operating and maintenance log books should include a benchmark for the system's performance in use. New performance standards for boilers, heating and hot water systems should also see big improvements in energy efficiency and the use of combined heat and power systems is also encouraged.

Efficiency of lighting will be included for offices and industrial buildings by stipulating an average efficacy taken over the whole building. Display lighting, which was excluded from the lighting provisions introduced in 1995, has also been included in the regulations, so it too will be covered under a new performance standard.

On the housing front, the proposals also include significant improvements in U-values. The big break for housebuilders is that the proposed method of calculation will take into account the efficiency of a dwelling's heating boiler. That means contractors will be allowed to use a slightly less arduous set of U-values when an efficient boiler is installed.