In this VoltiBULLETIN, Voltimum UK Managing Editor James Hunt introduces the topic of The Code for Sustainable Homes:
and very urgent problem. Emissions of so-called 'greenhouse gases' - carbon dioxide (CO2 ) mainly - are the main cause of climate change, the UK emitting over 550 million tonnes of it in 2005. Building energy use resulted in around 50% of these emissions, with over 25% coming from the energy used to run UK homes.
Indeed, over a quarter of the UK's total CO2 emissions come from heating, lighting and appliances in homes, with heating accounting for almost 75% of emissions given off. Space heating accounts for 53% of this figure; water heating 20%. Therefore, low carbon space and water heating solutions will be key to meeting the energy requirements of the Code for Sustainable Homes (CSH), of which more later.
It is not certain exactly what the result will be, but it is increasingly clear that it will be bad for everybody the world over, with worst scenarios even only a year or two ago now already looking like best scenarios today. Very urgent, direct and immediate action is being called for on many levels by scientists.
The Code:
This is the background to various pieces of climate change legislation affecting the UK construction industry, including the CSH, which was launched in December 2006. The CSH is intended to be a single national standard to be used in the design and construction of new homes by providing a set of sustainable design principles covering performance in several key areas. The CSH, therefore, sets a single national standard, within which the home-building industry can design and construct homes to higher environmental standards. Performance is measured across nine key sustainable design categories, including energy / CO2, water consumption, materials, ecology, pollution and waste.
There are six levels in the CSH. Achieving each level will result in a higher level of carbon emission reduction. Each category is assessed against a set of performance criteria - credits are awarded and an overall sustainability score calculated. From the Energy category, the Code requires a minimum mandatory improvement in CO2 emissions over and above Part L at each level of the Code as follows:
- Level 1: 10% reduction.
- Level 2: 18% reduction.
- Level 3: 25% reduction.
- Level 4: 44% reduction.
- Level 5: 100% reduction.
- Level 6: A zero carbon structure (including appliances).
The Code uses a one to six star rating system to communicate the overall sustainability of the home, with 1 star being above the standard of current building regulations, and six stars - the highest rating level, meeting the 'Zero Carbon Home' requirement.
The star rating works as follows - a minimum number of points, which have been obtained from the credits available for each category, are needed to achieve each star rating. For some categories, especially Energy, minimum mandatory standards apply at each level of the Code, which must be met - in addition to the required points total (see CSH time line below). Once the mandatory minimum standards have been achieved, designers can choose how many credits from other Code categories they wish to obtain to meet the desired star rating for a given home. This provides significant design flexibility in terms of meeting the CSH.
How the Code works in brief:
While for the private sector the Code is a voluntary standard, it is mandatory
for all new homes to be marketed with a Code rating (even if zero) - so as to encourage demand for better homes. Future proofing will be important, as credits are awarded for this in terms of improving energy efficiency over building lives by limiting heat losses.
In the public sector, Code level 3 has been adopted as the current 'Best Practice' standard and all social housing is required to meet Level 3 as a minimum.
Local planning authorities are also adopting the Code - either in full or, as a minimum, the Energy section - in order to improve building standards regionally. It is increasingly becoming a condition of planning consent for new developments to meet a specified Code level, frequently Code Level 3. Note that it is expected that most planning applications will require a full CSH Assessment at the planning submission stage. Under the new CSH rules, local planning officers can request that planning application complies with one of the six Levels mentioned, though many local authorities are said to have bypassed Levels 1 and 2, and have a minimum requirement of Level 3 on all applications.
Note also that the most significant point scoring opportunity within the CSH is the Energy category, which accounts for the highest number of scoring points, and which also has mandatory minimum standards at each level. Maximum CO2/m2 energy targets are set at an improved level over those required by Part L1A of the Building Regulations. The minimum required improvement in CO2 emissions varies at each level of the Code, which, therefore, indicates the direction for future amendments to Building Regulations Part L. Step changes in maximum permissible CO2 emissions are being tied closely to the various Code levels (see again 'CSH time line' below).
The CSH also provides technical guidance, which includes a list of technologies considered to provide low-zero carbon emission building services. These include heat pumps and solar thermal hot water systems, among others. It is probable that these will be required to meet higher Code levels. However, higher levels of building air-tightness are also required. This usually means adoption of mechanical ventilation to ensure high air quality within a building. To minimise energy consumption and maximise CO2 savings, mechanical ventilation/heat recovery (MVHR) units should be specified.
The criteria for assessing sustainable housing changed in April 2007 when the CSH replaced the BRE's EcoHomes scheme in England. A significant difference between CSH and EcoHomes is that the latter is based on the overall rating for the site - location, ecology and amenities, but CSH assesses the sustainability of individual dwelling types against specific design categories.
CSH time-line:
- Private sector (energy): 2007 - Voluntary; 2008 - Assessment mandatory; 2010 - Level 3 (25%) mandatory; 2113 - Level 4 (44%) mandatory; 2016 - Level 6 'Zero Carbon' Home mandatory.
- Public sector (energy): 2007 - Level 3 (25%) mandatory; 2010 - Level 4 (44%) mandatory; 2013 - Level 6 'Zero Carbon' Home mandatory.
Standard Assessment Procedure (SAP):
The SAP is the Government's recommended system for energy rating of dwellings, and it is used to calculate the SAP rating (on a scale 1 - 120), based on a building's annual energy costs for space and water heating, and to calculate the Carbon Index (scale 0.0 - 10.0), based on the annual CO2 emissions associated with space and water heating. The resulting SAP rating helps fulfil the requirements of the Building Regulations to notify and display an energy rating in new dwellings.
Note that SAP2005 includes an Appendix Q scheme for MVHR systems. Go to www.sap-appendixq.org.uk
Planning applications under CHS:
In order to submit planning applications, those concerned must either provide a 'Pre-Assessment CSH', or a full CSH, to the required Levels (1 - 6). Guidance can be provided by planning officers.
A Pre-Assessment involves three main stages:
- Stage 1: The SAP calculation.
- Stage 2: Upgrading the SAP to include the necessary reduction in carbon emissions (Levels 1 - 6).
- Stage 3: Providing an Upgrade Report that outlines how close the existing design is to achieving the required Code Level - to be set by the Local Authority planning department - plus any additional recommendations to meet the requirements.
If a Pre-Assessment is required, an SAP calculation and Upgrade Report on each dwelling must first be completed. A full CSH Assessment may need an on-site attendance.
Further information on compliance requirements for the CSH can be found in the CLG document 'Code for Sustainable Homes Technical Guidance', available from www. planningportal.gov.uk.
More information on the Code for Sustainable Homes:
The above article is intended merely as an introduction to the CSH.
Thanks are owed to Dimplex for help in the preparation of this article.
For further information in this VoltiBULLETIN, please click on the links below:Building for the future with Dimplex - ROUTEONE - This very useful PDF document has been designed to guide specifiers through the regulatory maze, by providing in depth, practical solutions to complying with Building Regulations and the Code for Sustainable Homes.
A specifier's guide to electric heating solutions - Part L - This PDF document from Dimplex is a specifier's guide to electric heating solutions - Part L, and it goes up to and including 2010.
A specifier's guide to achieving Code for Sustainable Homes - Level 3 using heat pumps - This PDF document from Dimplex, entitled 'A specifier's guide to achieving Code for Sustainable Homes - Level 3, with heat pumps', does just what it says.
Heat recovery ventilation leads the way in sustainable homes - The Code For Sustainable Homes (CSH) promises a step-change in sustainable home building practice. From April 2008, publicly funded housing will be required to build new homes to meet Level 3 of the CSH, with private sector developments having to follow suit in 2010. Ian Mitchell, Residential Product Manager, of Vent-Axia, explains how low carbon heat recovery ventilation systems can play a significant role in meeting these requirements.
Energy performance and sub-metering - There are a number of drivers affecting the energy performance in modern buildings, some of which impact upon the work of the electrical contractor, challenging him/her to produce cost-effective solutions but also presenting new business opportunities, as this article from Eaton Electric shows.
Eaton provides smart, sophisticated lighting controls for home or business - The updated 'Studio' dimming system offers advanced lighting control for both residential and commercial environments. It combines the aesthetic and practical features of the company's 'COPA' (Clip-on plate) range of wiring accessories with the proven technical qualities of its successful Studio 3 commercial lighting controls
Choose heating savers, not users - Bearing the Code for Sustainable Homes in mind, and as fuel prices soar and the credit crunch bites for businesses as well as consumers, it's more important than ever that installers and specifiers of heating are fully up to speed on products that provide energy savings. Phil Chilton, Dimplex commercial product manager, explains.
Renewable energy targets easily achieved using heat pumps - A business park on the south Cornish coast that has many energy efficiency features to provide cost savings for occupiers, has included Dimplex ground source heat pumps in its specification - and has quickly achieved its renewable energy targets.