Zero carbon homes are the next major target of residential construction in the UK. Since April 2008 each new planning application in England has had to reference the Code for Sustainable Homes (CSH). The Code uses a star rating, ranging from 1 to 6 stars, by which 1 is representative of a slight improvement upon Part L of the Building Regulations, and 6 is representative of zero carbon levels, which will be mandatory for every new build by 2016.
With zero carbon homes being the aim, the requirement to reference the Code will mean that it is necessary that each home is assessed against the CSH in order to determine its star rating. Several authorities such as Nottingham, Gloucestershire, and some London boroughs, already require that every new build in the area achieves at least 3 stars.
Zero Carbon Homes and The Merton Rule
Since 2005, various authorities have applied what is called ‘The Merton Rule’. This rule requires that any major development must generate at least 10% of the site’s energy using renewable sources. ‘Major’ in this context is taken to mean two or more dwellings, in order to safely exclude most self builders. However, this rule is increasingly being used to apply to all new dwellings, as we head towards the goal of achieving zero carbon homes across the country. The rule is being implemented more and more frequently because the zero-carbon rule will be applied to all new builds by 2016 and therefore it would make sense to begin implementing the rule as early as possible. The 10% renewable sources rule is not set in stone, with some authorities requiring 0%, and others requiring up to 25%.
Interestingly, a 3-star rating as determined by the Code will need at least a 25% improvement on Part L of the Building Regulations. However, it will require various other things too. To achieve a 3-star rating under the Code, the maximum water usage must be no more than 105 litres per person per day. This is easily put into perspective when you consider that at the moment the average UK household uses 150 litres of water per person per day. These are not the only requirements, and in addition any self builder will have to make great improvements to the sustainability of the materials they use, they must use sustainable drainage systems, limit the surface water run-off, keep pollution under control, and restrain the ecological impact of the home as much as is possible, amongst other things.
Reaching the 25% energy use improvement does seem a difficult target to reach, but it can easily be begun by reducing energy usage with low-energy fittings, better insulation in the home, and improved airtightness. Each of these is covered y the Code, but they do still leave the self builder with the need to generate their own energy on site.tagsemissionsenergyself buildzero carbon