Sustainability drivers

The most recent revision of the Part L: Conservation of Fuel and Power Approved Document of the Building Regulations was brought into effect as from 6 April 2014. The regulations have moved away from the historic u-values approach towards a system more closely tied to the amount of carbon being used by a building. This makes it a more complicated system to operate than the old u-value approach, usually requiring available software to be able to show how one's design achieves the requirement for reducing carbon dioxide emissions from the building by an average of 44% for both commercial and residential buildings, compared to the same buildings under the 2002 Building Regulations.

The 2010 revisions had treated the carbon reduction required for residential and commercial buildings differently. Residential buildings require a flat rate 25% improvement compared to 2006 regulations, which with the previous 25% reduction from 2002 to 2006 makes a total of 44%.

The 2010 revisions for commercial buildings, however, required a 25% reduction over carbon emissions under the 2002 Regulations, but with different rates for each building type. These averaged 25% across all of the commercial buildings types but in order to get best value (measured as increased construction cost against reduction of cost-in-use), studies showed that some buildings would incur a far greater cost to achieve a 25% reduction than others. Therefore, the rates set gave the same overall reduction of carbon across the range of sectors, but gave different percentage reductions for each sector; effectively, the cheaper it is to reduce carbon output, the greater the percentage reduction required:

• supermarkets require an 11% reduction;
• warehouses with rooflights 36% reduction;
• warehouse without rooflights 22%;
• shallow plan offices (heated) 27%;
• shallow plan offices (with air conditioning) 33%;
• deep plan offices (with air conditioning) 19%;
• hotel 25%;
• schools 23%; and
• retail 33%.

One new point was that in residential properties, 75% of all light fittings must be low energy.

The latest amendments came into force in April 2014. These changes were supposed to deliver another 25% saving against 2006 standards (i.e. a 58% reduction overall), however, the actual figure to be achieved is a 6% reduction in carbon emissions for domestic properties and 9% reduction for non-domestic compared to the 2010 Part L requirements. This is less than any of the options proposed in the consultation documents and was aimed at minimising the construction cost of new homes and commercial buildings during the difficult economic circumstances in the run up to the changes and given the lack of house-building across the UK.

This was intended to be a step towards the following update for 2016, with zero ‘regulated’ carbon for all new-build homes and for 2019 with zero ‘regulated’ carbon for non-dwellings (although the government had set a target for all new public sector buildings to be carbon zero by 2018). ‘Regulated’ carbon was only to include construction elements, i.e. the space and water heating, lighting, pumps, fans and cooling but excludes white goods. However, in July 2015, under its Fixing the Foundations: Creating a More Prosperous Nation plan, the government announced that it was abandoning the target for all new homes to be carbon zero from 2016 onwards. This cancellation of the zero-carbon target was subsequently extended to non-domestic buildings. There is currently no set date for when Part L will next be updated but it is expected to be by 2020 – but the levels of further carbon reductions are not known. With Brexit, the government will presumably provide revised guidance to counteract the EPBD obligation for new buildings to be ‘nearly zero’ energy by 2020. Local authorities may well begin to bridge this by including carbon targets in their own planning policies instead.

For the surveyor, it is important to track these planned changes, be aware of what their local authorities are including in planning policies and designing new developments and refurbishments to meet these new targets. Different design solutions will need to be assessed in order to value engineer the most cost-effective way of achieving the carbon reduction targets set locally.