Energy performance: improving the Standard Assessment Procedure

Getting on my SAP box

9 January 2017

Greater industry involvement could considerably improve the Standard Assessment Procedure, Dave Mitchell maintains

For an industry worth tends of billions of pounds a year, private housebuilding is sometimes provided with pretty inadequate tools. Indeed, in one particular area there is a growing body of evidence from housebuilders, the supply chain and organisations such as the Zero Carbon Hub to suggest that we are far from achieving value for money, while innovation is stifled and housing design remains poor.

So, let’s talk about SAP ... that is, the Standard Assessment Procedure. This is the methodology used to assess and compare dwellings’ energy and environmental performance, which is meant to provide accurate and reliable assessments to ensure approval under Part L of the Building Regulations.

Potential savings

To give you an idea of the savings that would be possible if SAP were knocked into shape, consider these very rough figures.

If, in 2016, the private sector completes about 140,000 new homes and they are each 80 sq. m on average, that amounts to about 11.2 million sq. m of dwellings in total. Let’s say building cost is £750/sq. m as it makes the maths easy, and that results in building costs of £8.4bn.

How much of that is affected by Part L and SAP? It will be all the fabric, including windows, most of the plumbing, heating and ventilation, and so on. So, with a finger in the air, shall we say around 25%? This means that around £2.1bn of work depends on SAP.

At the last count, the government spent less than £500,000 a year on SAP – and, to be honest, it shows. For this we get 100 or more pages of equations and diagrams. Anyone who wants to do so can then attempt to code this into software that is checked by BRE, which has spent its time doing the same.

After all the comparisons and contrasts, the various parties agree that the differences in their answers are small enough not to matter. As we know, this process still takes some time, especially when Part L changes. Quite often we are left in the lurch trying to make sense of a new Part L with a ‘consultation version’ of SAP rather than the real thing.

So you would think that when we, along with the materials manufacturers, have previously suggested to the government that we could help fund development and maintenance of SAP in return for more industry involvement and sight of the governance, we would have been met with an eager response. But the EU has insisted that member states rather than users must own and be in control of their respective national calculation methodologies.

While it may not be so in other areas, Brexit could be our friend here, and perhaps it is time to go back to the government and have the conversation again. We know from the experience of Robust Details that the industry can take a policy and develop a more user-friendly way of meeting the requirements. Robust Details also demonstrates that it can be both more cost-effective and enable higher performance – a win–win. After all, if we collectively spent, say, £2m a year on SAP to make it more accurate and realistic, we would only have to save £1 in every £1,000 of our Part L-related building costs to recoup the cost. From what every technical designer says to me, the inadequacies of SAP cost us a lot more than that.

So how far do we push it? Do we spend a little to save a lot, or just continue wasting good money on poor measures?

Dave Mitchell is Technical Director at the Home Builders Federation

Further information

  • Related competencies include Legal/regulatory compliance
  • This feature is taken from the RICS Building control journal (November/December 2016)