The timetable for the introduction of mandatory Energy Performance Certificates (EPCs) is now well underway. As of April 1^st this year, obtaining a certificate for all new dwellings and for the sale or rent of all new or existing non-dwellings with over 10,000m² of floor area will become law. By October 1^st 2008, certificates will have been phased in for all buildings regardless of size or usage. Certification consists of a simple grading from A to G for both energy efficiency and CO₂ emissions, and this increased transparency on building performance could mean that EPCs have an influence on saleability. It is, therefore, important both environmentally and financially to ensure buildings achieve a good EPC grade.

The Department for Communities and Local Government is responsible for implementing EPC assessment, and it asserts that buildings are responsible for nearly 50% of the energy consumed here in the UK. Along with European Commission research finding that better energy efficiency in all buildings could reduce related CO₂ emissions by as much as 22%, the importance of ensuring energy performance across all types of building could not be clearer. However, perhaps because EPCs are already required for some domestic buildings most attention has been focused on the certification of dwellings. Despite being a vital part of improving the country’s energy efficiency, information on the implementation of non-dwelling EPCs is currently hard to find.

Owners and developers of non-dwellings may be left wondering how they can gain a high EPC grade. Importantly, one thing we do know is that the Building Research Establishment’s Simplified Building Energy Model (SBEM) will be used to calculate EPC gradings for non-dwellings, and this gives us some useful information. SBEM conforms to the stipulations for energy performance calculation as set down by the Energy Performance of Buildings Directive, which outlines a number of mandatory factors. One of these is the assessment of a building’s thermal characteristics – how it retains and loses heat – including air-tightness. The thermal performance of a building is integral to its overall energy performance, and so a simple way to improve energy efficiency and therefore a better EPC grade is to specify building envelope materials with good thermal insulation and air-tightness properties.

This makes the specification and installation of efficient roofing and cladding materials an important factor in EPC assessment. What’s more, the diversity of usage in non-dwellings could cause more uncertainty, so choosing to focus on improving a common feature such as envelope performance is a relatively safe and effective method for better EPC achievement.

An excellent way to improve a building’s thermal characteristics is to use an insulated panel system for the roofing and cladding. High thermal performance means these products can make an enduring and positive impact on a building’s energy efficiency. For example, where a 100mm composite insulated roofing panel with a PIR insulating core is installed correctly, a U-value as low as 0.20 W/m²K can be achieved. This means minimised thermal transmittance through the roof and greater energy efficiency. Another important feature is factory formed jointing, which offers optimised air-tightness of at least 5m³/hr/m² or better, together with excellent thermal continuity. Similar performance can be achieved for walls, thereby forming a highly energy efficient building envelope.

Composite insulated panels also have characteristics useful in light of the requirements for  Display Energy Certificates (DECs), which will be mandatory on all public buildings over 1000m² from 1^st October 2008.  This will include central and local government buildings, schools, universities and hospitals, amongst a range of others The DEC is issued after the calculation of two factors: an Asset Rating (AR) based on design performance, and an Operational Rating (OR) based on actual building performance. Because certification is seen as a long-term driver for improving energy efficiency the certificate has to be renewed every 12 months.  If reliable and durable envelope materials have not been used, the building’s grade and energy performance could decline significantly over time.

This means public building owners, developers & design teams need to consider energy efficient solutions that can offer lifespan reliability if they are to ensure performance is maintained. The durability of composite insulated panels throughout the life of a building can help to maintain a high OR, whereas over time some insulation materials can be prone to poor performance. Mineral fibre, for example, has been known to suffer degradation when exposed to air movement, meaning a greater chance of the need for expensive replacement work. Composite insulated panels are not affected by air movement, or attacked by mould, fungi or mildew, making them a reliable long-term option.

Deterioration of ORs over time may not only have implications for the planet in terms of increased emissions but may also have liabilities for design and construction teams.  The use of materials with excellent long term thermal durability is essential.