SAP 2012 Consultation

A consultation on the Government’s Standard Assessment Procedure (SAP) for domestic energy use was released last week.

Not yet available is the related and eagerly awaited CLG consultation on the Building Regulations Part L 2013. It is this second consultation that should contain details of the next big step-change in housing standards taking us towards zero carbon new homes. It is also expected to establish stricter requirements for the refurbishment of existing homes. The Part L consultation has been somewhat delayed but is expected by the end of the month

In the meantime we have reviewed the proposed technical tweaks to the calculation methodology for SAP 2012. Perhaps most significant is what has not changed. A list on the very first page of the consultation acknowledges a number of improvements that will be deferred until the next revision of SAP, due in 2015. Many of these deferred improvements are the ones that have been most sought by industry. The reason given for the delay is that there is there is a lack of available technical data.

As a practice we are concerned that SAP for new buildings should be able to accommodate emerging technologies and reflect as closely as possible the performance of low energy dwellings. A SAP method that gives designers maximum flexibility to use innovative strategies is needed. We have seen in the past that SAP drives product innovation and improved efficiencies. Still missing from the SAP method for example are the use of solar panels for space heating, adjustments for different types of low energy lighting, and low temperature circulation to heat emitters. These are technical areas which could benefit from renewed interest generated by SAP. While SAP in 2015 will be associated with Part L1a 2016, which is planned to be the ultimate version of the Building Regulations to deliver the Zero Carbon Home. It would have been better for industry to have had access to a SAP method that approximates that version well ahead of time.

Our first impression, is that the proposed updates to the SAP in 2012 are not particularly radical. One change that will have an impact away from the production of Energy Performance Certificates is that a further a step has been taken toward the use of regional climate data. While national average data is to be retained in some key parts of the calculation, weather data will now be extended beyond the cooling calculation to determine, for example, running costs underlying the EPC;  the calculation of Fabric Energy Efficiency (the FEE), calculation of summer overheating risks and the output of solar renewable technologies. Adopting regional Weather Data for reckoning the outputs of solar thermal heating and PV Panels will be significant for the uptake of the Feed In Tariff (FiT) and the Renewable Heat Incentive (RHI).

There are also changes to methodology for calculating the efficiency of heating systems, which will impact on manufacturers, as well as new carbon factors for fuels. Carbon factors used in the regulations are important for establishing the CO2 emissions of UK PLC, and are often controversial, though there are no very large adjustments this time. CO2 emissions associated with gas are up by 7%; the CO2 associated with grid electricity is up by 1%. An interesting development is a new distinction made between a three year projection of carbon factors for all fuels, and a 15 Year Projection of CO2 factors for a smaller set of key fuels.


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