Disclosure and display

Tony Blair recently announced his ambition to bring all the world's major countries into consensus on the urgency of reducing greenhouse gas emissions and has emphasised the need for the UK to lead by example if his cajoling is to succeed. One of our first opportunities will come through our implementation of the Energy Performance of Buildings Directive (EPBD) which must be brought into national legislation by 4 January 2006. Government proposals for how this should be done are currently out for consultation¹.

Building Regulations have historically set minimum standards for new buildings to ensure that the imperfections of the market economy do not result in low cost, poor performance outcomes. Part L is intended to protect owners and occupiers against high fuel bills as well as contributing to broader national energy policy objectives, including energy security. The EPBD is looking to strengthen and harmonise building energy performance regulations across the EU. But this only affects the relatively small proportion of individuals and organisations involved with new buildings or refurbishment. Somehow the message that greenhouse gases are threatening the future of our civilisation must be got across to every member of society so they can take responsibility for reducing their emissions.

One prerequisite for an effective response is to put energy labels on 'everything'. So, moves are afoot to require all cars to display an energy label on their number plate. Meanwhile, with nearly half of all CO₂ emissions arising from buildings, the EPBD aims to raise the issue with everyone involved in the construction, alteration, sale or rental of property as well as with anyone visiting a public building – a radical signal that existing buildings are a part of the problem. It will do this by requiring an energy certificate to be available on the sale or let of nearly all buildings and displayed prominently in larger public buildings.

Initially the labels will be for information only. However raising awareness is only the start. Given our addiction to high carbon lifestyles stoked by pervasive promotion by our growth-dependent economy, altruism or even fashion are unlikely to be enough to initiate sufficient actions to reduce emissions. This is particularly true, given the target set in last year’s energy White Paper to reduce emissions in the UK by 60% from current levels by 2050, let alone by the 85% necessary if the Contraction and Convergence plan is adopted.

Tony Blair heralds a new age of low carbon energy supplies and ultra efficient end use, implying hardly a murmur on the nation's heart-beat as we undergo the transition. Others forecast a need for draconian carbon rations including a severe curtailment of how far we all travel. At the very least, unless energy prices rise considerably, it seems inevitable that labelling buildings will need to be followed up by some tangible reward for better performance, such as reduced rates of stamp duty or council tax.

For now, it is just fifteen months before the EPBD will be law. Time is closing in on legislators, their advisers, design consultants and their clients. Few people question why it must be done, but there are still some big what, how and when questions.

What is a public building?

What will be the definition of a public building in the UK? This is one of the biggest issues that Brussels has delegated to national decision makers. The directive states it is ‘buildings occupied by public authorities and by institutions providing public services to a large number of persons and therefore frequently visited by these persons’. Does this mean buildings that do both these things, or only one of them? ODPM's consultation document suggests it should be only public sector buildings regularly visited by members of the public, eg public libraries, sports centres, schools, universities and hospitals. However, the preamble to the directive (which has guidance status rather than the legal standing of a directive's articles) states that ‘public authority buildings and buildings frequently visited by the public should set an example…… by clearly displaying energy certificates’. This raises the prospect of requiring privately owned buildings frequented by the public, eg hotels and supermarkets, to display an energy certificate. And why not? It would only be asking them to make transparent their contribution to the most serious environmental challenge facing the world today. If this would encourage them to reduce that impact in a cost-effective way, it must be a good idea. Government estate buildings not visited by the public could also declare their energy performance in web sites, annual reports etc.

How will an energy certificate be drawn up? This also is left to member states to decide although CEN standards are now being prepared to allow a harmonised, albeit flexible European approach to materialise eventually. The two key elements of a certificate will be a headline energy performance grade (eg A to G as on white goods) and a list of recommended (and cost-effective) energy saving measures.

Most attention to date has been focused on whether the headline grade should be based on a calculated theoretical performance or determined by the building's actual energy consumption, as measured by meters, etc. And a consensus now seems to have formed (see Table 1).

For new buildings, the EPBD certificate is required on completion. ODPM proposes that this will be an ‘Asset rating’, the result of the same calculation which produces the ‘Design" rating’ proposed to satisfy Building Control, but taking account of the as-built building, eg the plant actually installed, measured airtightness and commissioning data for specific fan power.

The directive requires the certificate to count only the energy used for the following building services: heating, hot water, ventilation, cooling, humidification and lighting – assuming a standardised use of the building (in many cases the future occupants of the building, let alone how they will use it, will not be known when the building is completed). For simpler non-domestic buildings, a national calculation tool is being suggested, either an implementation of the CEN standards or a customised version of the US's EnergyPlus; for complex ones it is proposed that accredited commercial simulation packages be used.

The certificate required for the sale or let of an existing building should be based on an equivalent calculation, to allow direct comparison of all buildings on the market, both new and existing. However, for existing buildings, plans and specifications of what is actually there are often hard to come by, so data collection for the proposed procedure could be time consuming and expensive and the results potentially lacking robustness and repeatability. The current proposition is to develop an ‘inference engine’ to standardise and streamline the data input process.

How does the ‘Operational rating’ based on annual energy use fit in? For most existing buildings, metered data could be obtained relatively easily. However, this is not necessarily appropriate for the sale/let trigger as it will relate to use by the previous occupiers, not the new ones for whom the certificate is intended. The ‘Operational rating’ will take account of all energy used in actuality, not just normal building services end uses under standard conditions of climate, occupancy, control and management. The way around these differences is to compare ‘Asset’ and ’Operational’ ratings not in engineering units (say kg CO₂/m²/year), but by A to G grades. The ‘Asset grade’ can be produced by comparing the ‘Asset rating’ with commensurate reference values (eg for building regulation compliance) and the ‘Operational grade’ is obtained by comparison with in-use energy benchmarks (eg Action Energy's good practice and typical values).

The ‘Operational rating’ has two principal uses. The first is for display in public buildings, where the certificate is triggered not by a change of occupancy or ownership, but to inform the occupier and the public about the true energy efficiency of the building and the scope for cost-effective improvement. Here, to base the certificate on measured not theoretical energy use is not just relevant but essential to a meaningful rating; the energy performance of buildings in use rarely matches up to design expectations, (for example as demonstrated by the PROBE studies²) and there is often scope for rapid improvement.

Secondly, for new construction and major alterations, ODPM is proposing that the Operational Rating should be produced within three years of the practical completion of building work. This will allow for fit-out etc and give time for a full year of stable operation. To have both the ‘Asset’ and ‘Operational’ ratings will help to close the credibility gap between design intention and reality. This statutory feedback will help the building's owners and occupiers to engage with getting the building's performance on track (if it's not already there), while the procurement and design team will learn what is working well, what isn't and why.

Energy certificates will be required on the sale or let of nearly all buildings and will need to be displayed prominently in larger public buildings.

The consultation document therefore recommends that an energy certificate should have space to show both ratings, with the Asset Rating being mandatory for completion, sale or rental and the ‘Operational rating’ mandatory for public display. When both ratings exist, they should both be displayed (see figure 2).

The Europrosper project³ produced a proof-of-concept methodology for determining an ‘Operational rating’ for office buildings, and was successfully tested by 79 users across 13 of the EU-15 countries. The method has the following main steps:

• Calculate the building's energy intensity (eg in kg CO

• Determine how the energy supplied is broken down by end use .
• Analyse and prioritise potential energy efficiency measures for their cost effectiveness and calculate the potential improvement in the energy efficiency grade.
• Produce an Energy Certificate which reports all of the above

Step two of the procedure for offices uses the ECON 19 tailored benchmarks approach developed and implemented in software by William Bordass Associates following a feasibility study for Action Energy. Here, customised benchmarks are created from the schedules of accommodation, levels of occupancy and equipment, and hours of use of the activity areas in the actual building and calculating the annual energy requirement for each, assuming good practice or typical energy efficiency for the building services present.

A follow-on project called EPLABEL is currently being negotiated with the EC and UK government. This will review the methodology (in particular the benchmarks) and extend it to six key non-domestic sectors which might fall under the public building designation: public administration, higher education, schools, sports facilities, hospitals and other public health facilities and hotels and restaurants. The main deliverables will be a public domain web site to generate customised energy benchmarks for buildings in the six target sectors and a training package for the engine for accredited (Article 10) experts and self-assessors.

The project will also work to overcome delivery barriers to make the procedure practical yet technically robust and deal with institutional arrangements, for example between landlords and tenants. Data processing proposals will be developed which can support the synthesis of energy certification results and the periodic refinement of energy performance benchmarks. Seventeen of the EU-25 countries are participating, together with Norway and Switzerland.

When will certification begin?

When will energy certification kick in? With so much undecided and several hundred thousand public buildings around Europe required to display certificates, one can understand why the Directive allows Member States to apply for an extension of time for full compliance with the certification requirements. However, the only allowed justification is a "lack of qualified and/ or accredited experts" which must be notified to the Commission along with a timetable for a phased implementation, presumably covering a matrix of the three main triggers and each building sector. Phased introduction will allow expertise to be built up steadily and reduce the large peak in initial certification activity for public buildings and the echo in ten years time when these first certificates will expire if they are not renewed in the meantime. The poor level of compliance experienced with the mandatory display of SAP ratings in new dwellings on sale since 2002, suggests that enforcement and policing policies will need to be established – and probably financial incentives as well. In Denmark, a 60% compliance rate has been achieved for an energy certification scheme which has been mandatory for larger buildings since 1997.

The issues described in this article are all raised explicitly in the ODPM's consultation document. The deadline for responses is 22 October. Implementation of the EPBD will be one of the largest outside influences yet experienced on the world of buildings. Now is the time to offer your views on how it should be done in the UK.

Robert Cohen is a principal consultant at Energy for Sustainable Development and co-ordinator of the Europrosper and EPLABEL projects. E-mail: robert@esd.co.uk

References

¹Proposals for amending Part L of the Building Regulations and implementing the Energy Performance of Builidngs Directive: A consultation document, July 2004.

²PROBE was reported by BSj from 1995 to 2002. Visit: www.usablebuildings.co.uk

³Visit: www.europrosper.org