Zero carbon homes: house builders give their perspective

A new study has surveyed major house builders in the UK to understand what is needed if all new homes are to be zero carbon by 2016. The house builders generally felt that it is not an impossible challenge, but a comprehensive approach with clear guidelines, supported by necessary legislation is required.

The results provide important lessons for sustainable construction programmes in other countries. In April 2009, the European Parliament voted on amendments to strengthen a proposal of the European Commission to recast the Energy Performance of Buildings Directive (2002/91/EC)1.

The residential and tertiary sector, the major part of which is buildings, accounts for more than 40 per cent of energy consumption in the EU. Europe could thus make a considerable contribution to meeting Kyoto targets by applying tougher standards to buildings.

The UK has set itself a 'world- beating' target: aiming for all new homes to be zero carbon by 2016 in its 'Code for Sustainable Homes', published in 2006. In order to be zero carbon, buildings must generate as much energy as they consume.

The Code for Sustainable Homes uses environmental impact rating system of 1 to 6 to indicate overall sustainability of a new house: a rating of 6 equates to a zero carbon home, which specifies that required domestic energy must be generated from renewable sources. This exceeds other international housing standards.

For example, Germany's 'PassivHaus' sets a maximum level of energy usage (15 kWh/m2 a year for heating and cooling), but does not specify the source of energy.

The house builders' responses to the survey suggest:

* The Code for Sustainable Homes is a significant driver of zero carbon homes.

* New technologies and products would also significantly help builders achieve the target. Zero carbon homes are not considered possible with today?s technologies and so the supply chain is seen as a major barrier. Sufficient resources are needed for the government and building industry to research and develop appropriate and cost-effective technologies.

* There are no financial incentives for producing zero carbon homes. Additionally, there is much uncertainty about how much it will cost to build a zero carbon building, but it is generally considered to be more than a standard house.

* The most significant legislative barrier was an unclear definition of 'zero carbon'. Builders were unsure of the requirements, for example, the need to provide onsite renewable energy. Appropriate guidelines would be beneficial. For instance, does renewable energy distributed at a district level by Energy Service Companies (ESCos), rather than onsite, count towards zero carbon status?

* There was concern over the reliability of renewable technologies. An alternative and more cost-effective solution to providing onsite renewable energy would be to distribute renewable energy from ESCos.

* Consumers need to be made aware of the benefits of zero carbon homes, although there have been recent signs of increased demand for such homes. As such, the house builders called for the government to act upon this growing demand and legislate to create a national market for zero carbon homes.�

http://europa.eu/scadplus/leg/en/lvb/l27042.htm�

�www.planningportal.gov.uk/england/professionals/en/1115314116927.html

�Source: Osmani, M. and O'Reilly. (2009). Feasibility of zero carbon homes in England by 2016: A house builder's perspective. Building and Environment. 44:1917-1924. Contact: [email protected]��