The official launch of RdSAP 10 on the 15th June. now is the time to make sure you’re fully up to speed with the upcoming changes. From expanded ventilation options and detailed window measurements to the inclusion of air pressure test results, RdSAP 10 represents the biggest shift in assessment methodology in years.

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Why is the methodology being updated?

As one of the most extensive overhauls to the RdSAP methodology in a number of years, RdSAP 10 aims for increased accuracy of assessments, bringing them in line with modern technologies and building practices. The changes also reflect the Government’s continued push towards Net Zero.

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Summary of Key Changes

Below you can find a high-level summary of the key updates to the methodology for RdSAP 10.

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Room in the Roof

Assessors can now choose between two distinct Room in Roof types, and for each, must specify whether the assessment will follow a simplified or detailed method. These changes require additional measurements, including dimensions of gable and where necessary common walls, to accurately reflect differing construction types. The aim is to improve the precision of energy assessments by capturing the unique characteristics and thermal performance of these spaces.

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Windows

In one of the biggest changes for assessors, all windows must now be measured for an RdSAP 10 assessments. Additional options will also be available, such as frame types and permanent shutters, and the glazing age categories have been expanded to better align with regional standards and installation dates.

 

Ventilation (including Air Pressure Test Results)

Ventilation options have been extensively expanded for RdSAP 10 to include multiple new options as well as increased data collection required. This includes options such as open fireplaces, chimneys and flues to name a few. Mechanical ventilation systems are now much better supported with increased input options.

Air Pressure test Results

As part of RdSAP 10, air pressure test results can now be included where documentary evidence is available. By including measured air pressure test results, it provides the opportunity for a building’s performance to be more accurately recorded within the assessment, offering a better representation of its energy efficiency.

Walls, Roof and Floors

RdSAP10 introduces enhanced options for walls, roofs, and floors to improve the overall accuracy of the assessment. Assessors can now specify two alternative wall types per building part and wall insulation options are more detailed, allowing for the recording of actual thicknesses and, where evidence is available, thermal conductivity values.

For roofs, a broader range of insulation thicknesses is now available, and a new option has been added to account for non-residential or unheated spaces above, such as commercial units above flats. Similarly, retrofitted floor insulation can now be recorded with precise thickness options.

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Other Notable Updates

• Lighting: The number of bulbs must now be collected, not just the number of fittings, and it should be identified how may are LEDs or CFLs.

• New technologies: PV battery storage, diverters, and even small-scale hydro generation are now recognised.

• Water Heating: Cylinder size can now be accounted for. Heat loss can also be accounted for if documentary evidence is available.

• Heated Basements: More detail included and additional construction options to choose from, with specific u-values applied to walls and floors to better represent the space.