Sustainable construction services

New energy performance rules imminent for residential development

The Government’s Standard Assessment Procedure (SAP) for assessing the energy performance of residential units is being updated.

SAP covers the energy cost rating of a dwelling and has not been updated for seven years. SAP10 has been issued but has not yet come into force, although its launch date is imminent and developers are being encouraged to prepare for it as there are a number of changes compared with the current version, SAP2012.

The SAP rating is based on the energy costs associated with space heating, water heating, ventilation and lighting, less cost savings from on-site energy generation technologies and comes in the form of a score between 1-100 with the higher the number corresponding with lower running costs.

The calculation takes into account a range of features affecting energy efficiency including materials used for the construction of the dwelling; thermal insulation of the building fabric; air leakage ventilation characteristics of the dwelling, and ventilation equipment; efficiency and control of the heating system(s); solar gains through openings of the dwelling; the fuel used to provide space and water heating, ventilation and lighting; energy for space cooling, if applicable and renewable energy technologies.

The score is not affected by factors such as the size of the household or efficiency of electrical appliances within the dwelling.

SAP 10.1’s calculations now takes account of the shower flow rate in its analysis of hot water consumption for more accurate estimations, the calculation of lighting energy has been updated to allow for the lighting efficacy and amount, the air flow rates relating to chimneys and flues have been updated – the assessment of summer internal temperatures has been amended and the amount of ventilation that designers can assume is being gained from open windows has been reduced, additional flow temperature options have been provided for heat pumps and condensing boilers, and the assumed standard heating has been updated to cover all seven days equally with the thrust of the regulations focusing on greater accuracy of figures.

The CO2 emission factor for electricity will be reduced from 0.519 kgCO2/kWh to 0.233 kgCO2/kWh which means switching from gas to electric heating is more viable but the impact of Solar PV against a SAP assessment will be reduced, which may also mean that more PV will be required in order to achieve local planning requirements on major developments. Excess electricity from PV panels, however, can be stored under the impending rules.

Synetgra’s Energy Certification team undertake Part L Building Regulations compliance assessments for domestic and non-domestic properties across the United Kingdom under part L of the Buildings Regulations which will be updated to reflect SAP10.1 in due course.

Our team of Qualified Low Carbon Energy Assessors can undertake Part L compliance and EPC assessments  and our energy models are based on industry recognised 3 dimensional software which produces accurate energy and CO2 ratings of your property and will provide guidance on maximising energy & cost savings.

We provide consultancy services for:

  • Thermal bridging calculations
  • U-Value calculations & Heat loss calculations
  • Part L1A (New Dwellings)
  • Part L1B (Existing Refurbishment & Extensions)
  • Part L2A (Non Domestic New Buildings)
  • Part L2B (Non Domestic Refurbishment & Extensions)

Until SAP 10 comes into force (and once Part L/Section 6 is updated), SAP 2012 will continue to provide the structure for Building Regulations compliance and EPCs.

* In 2015, world leaders agreed to 17 goals for a better world by 2030. These goals have the power to end poverty, fight inequality and stop climate change. Guided by the goals, it is now up to all of us, governments, businesses, civil society and the general public to work together to build a better future for everyone. Syntegra’s work is underpinned by many of the goals.

Global Goals 13: Climate Action

Take urgent action to combat climate change and its impacts


Integrate climate change measures into national policies, strategies and planning.