The department for Communities and local Government released their latest report on achieving zero carbon compliance in all non-domestic buildings by 2019. This is part of the government's overall aim of having all buildings zero carbon by 2019.
Since the last report in 2009, there have been numerous changes and updates in legalisation and regulations, prompting CLG to re-evaluate the zero carbon targets set. There are a number of key recommendations to come out of this report including:
- The energy efficiency standard should be based on an appropriate envelope specification, with a separate set of minimum efficiencies for the main services equipment. This integrates with the design process as fabric measures are the principal domain of the architect whereas the services measures are the principal domain of the services engineers. The envelope standard should focus on achieving an appropriate balance between reducing space heating, space cooling and electric lighting demand.
- A set of minimum fabric elemental standards offers the best overall approach to standard setting. This is a continuation of the traditional approach in Part L.
- The maximum fabric U-values should remain as currently implemented in Part L 2010. There appears little, if any, benefit in increasing the minimum standards further.
- Further consideration is necessary as to the minimum standards for air permeability and thermal bridging.
- Improvements to the efficiencies of building services provide a cost-effective means of moving further towards zero carbon.
It also suggests that further education for builders and developers on the impact of facade design on Part L compliance would be preferred to incentivising schemes for achieving zero carbon.
It should be noted that the zero carbon objective applies to the building energy demand and does not take into account process plant and equipment.
The main issue moving forward is to prevent well insulated buildings over heating particularly in urban areas; the difficulty with the new proposals is maintaining a balance of adequate daylighting without excessive solar gain and ensuring that ventilation provisions are adequate without expensive mechanical ventilation systems which could have a high energy demand.
Energy metering and sub metering is already a requirement in certain non-domestic buildings, however, it will essential to sub meter the energy in buildings under the 2019 requirements.
The government may see new build as an easy target, however, the reality is that the majority of carbon emissions from buildings are from old, poorly insulated buildings and although new buildings achieving zero carbon by 2019 will help the overall problem, the reality is that it is just scratching the surface in reducing carbon emissions in non-domestic buildings.
There is a government commitment to make all buildings zero carbon by 2050. In order to achieve this, the whole energy infrastructure needs to be redeveloped by replacing volatile fossil fuels such as gas which is increasingly supplied by other countries to sustainable solutions such as off shore tidal, and wind. The government has incentives such as "The Green Deal" proposed for 2012 which may assist existing building owners in improving existing building stock.
Richard Smith
Technical Manager
