Domestic Energy Assessors (DEAs), including myself, were required to complete additional training to comply with the updated methodology, known as RdSAP 10. This stands for Reduced Data Standard Assessment Procedure, version 10, which replaces the previous version, RdSAP 9.94.
This marks the most significant change to EPCs in over a decade.
Under RdSAP 10, DEAs must now collect more detailed information during on-site assessments, which means the process takes longer than before. As of the time of writing, the areas requiring the most additional detail are windows, ventilation, and lighting.
For example, when assessing windows, DEAs must now measure each individual window to record:
- The glazing area
- The glazing type
- Frame material
- Glazing gap (the distance between panes in double glazing)
- Location within the property (main building or extension)
- Presence of a permanent shutter
- Orientation (e.g., north-, south-facing, etc.)
In general, the level of detail required has increased significantly. Previously, it was sufficient to note whether a property had a single-rate or dual-rate electricity meter. Now, assessors must also identify whether the property is equipped with a smart meter.
While the new methodology adds complexity and time to the assessment process, it results in more accurate and informative EPC reports. Ultimately, this is a positive development for landlords, homeowners, and tenants, as it provides a clearer picture of a property’s true energy performance.