DOCUMENT L CHANGES MAKE CHIMNEYS MORE POPULAR THAN EVER Changes to Building Regulations Document L are set to make chimneys more popular than ever as their benefits in terms of carbon savings and fuel versatility come to the fore.  Under the new rules, incorporation of chimneys/flues in domestic properties will normally give developers ‘carbon credits’, provide the opportunity for savings to be made in other elements of construction and offer a choice of secondary heating that will add to the sales appeal of properties. Central to the renewed appeal of incorporating a chimney is the calculation method to be adopted in Part L from April 2006. This requires the energy efficiency and hence carbon output of the whole property to be calculated so as to meet government targets designed to achieve a 20 per cent saving in carbon emissions.  As a result, any elements which are likely to increase the use of energy must be balanced by greater thermal efficiency within the building envelope – and vice versa. The calculation method assumes electric heating is the ‘default’ form of secondary heating. The benefits of installing a flue, used in conjunction with one of a number of gas, multi-fuel or wood burning appliances, arise because electric is a carbon intensive energy source. Explains the Chimney Development Association: “Where a chimney is installed in conjunction with a modern, efficient heating appliance this will offer a carbon positive benefit, relative to electric heating.  This saving then potentially allows economies in other aspects of construction, such as thermal insulation requirements and glazing specifications.” The carbon benefit is a key factor likely to encourage incorporation of flues in new homes.  However, it is by no means the only advantage. A correctly specified flue will provide the developer with a choice of heating appliances, enabling the builder to offer alternatives to the purchaser and so enhancing the bespoke element of the property – and its sales appeal. Chimneys and the ‘fireplace’ remain a highly desirable aspect of the home with much documented evidence of their appeal to the purchaser from an aesthetic, lifestyle and comfort viewpoint. They also provide an element of fuel independence. Under the new rules, builders can gain carbon credits when using open fronted fires with convector gas, wood and multi fuel burners, open fronted deep and shallow bed fuel effect fires. The benefits are greater still with glass fronted wood burning stoves and inset cassette fires.   More detailed information on flue specification in accordance with the new Document L requirements is available from the Chimney Development Association, part of the British Flue and Chimney Manufacturers Association, at www.chimneys-in-houses.com