SAP is a topical subject currently! The current method for calculating the energy performance of dwellings is based on SAP2012 & uses out of date information to assess the impact of electric heating on building design. The good news is things are changing with the proposed introduction of SAP10 in 2019/20.
Since 1995, all new dwellings require a SAP Assessment to meet Building Regulations. Some conversions, renovations and extensions may also require a SAP Assessment (your architect can advise on requirements based on the particulars of your project, and there are differences in England & Wales, compared with Scotland and N. Ireland depending on local Building Regulations). It’s important to engage a SAP assessor at an early stage of new building design, and before submitting a Planning Application, to avoid potential issues later in the project lifecycle. Once construction is underway, remedial measures can be difficult if not impossible to implement.
SAP & HEATING
Heating, and heating controls are a major element of SAP so important design decisions should be made at an early stage to ensure compliance.
SAP works on a range of baseline measures, and in the case of heating, mains gas is used as the baseline. Over 4m UK households do NOT have access to mains gas, and over 2m households use electricity for heating. Furthermore, the use of electric heating is increasing.
In real-terms, using mains gas for heating makes a SAP pass easier at present, because SAP2012 applies lower CO2 emissions from a gas central heating system (216g CO2/kWh) than electric (519g CO2/kWh).
These emissions factors are out of date and are due to be updated in SAP10.
What is changing?
Changes to the electricity related CO2 emissions in SAP10 are significant – reducing from 519g CO2/kWh to 233g CO2/kWh, now only slightly higher than mains gas (210g).
Currently SAP2012 assumes any electricity used in the dwelling produces 2.4 times the CO2 emissions of mains gas – this is because it uses an outdated carbon factor which does not reflect the energy mix of the UK grid. As the electricity grid becomes cleaner with renewable deployment, it is only a matter of time before electric heating becomes the cleanest heat source, and the move towards zero carbon becomes a reality.
Herschel Infrared is already the most appropriate heating solution in many applications. SAP10 is still in draft but when it becomes part of building regulations (anticipated late 2019) this will mean that Herschel Infrared becomes an even more attractive heating proposition. To discuss your project please contact our office on 01473 760320.
If you’d like to read our article “How SAP works with Herschel Infrared” please get in contact by emailing Andy Baird.