EPC lighting changes under RdSAP 10 mean the way lighting is assessed for Energy Performance Certificates (EPCs) has changed significantly to improve accuracy. Unlike previous versions where lighting was evaluated based on the type of light bulbs in each fittings, assessors now count every individual light bulb in the property. Each bulb is recorded and classified according to its type whether it is an LED, CFL, or incandescent bulb.

This more detailed approach means the EPC calculations can better represent the actual energy use of lighting in the home. By identifying the number and types of bulbs, the EPC model can differentiate between energy-efficient lighting, such as LEDs, and less efficient options like incandescent bulbs. The software now calculates lighting efficiency based on the proportion of low-energy bulbs (such as LED or CFL) to the total number of bulbs in the home. Properties with a higher number of inefficient bulbs (e.g. halogen or incandescent) may now see a slightly lower EPC score than under the previous methodology.

The EPC lighting changes change reflect the widespread adoption of low-energy lighting in UK homes while still accounting for any remaining inefficient bulbs. This allows homeowners to see how lighting choices impact their energy performance rating and encourages upgrading to more efficient options where possible.

By moving away from assumptions based on fittings and focusing on actual bulbs, RdSAP 10 provides a more realistic and tailored assessment. This contributes to an EPC that better represents a property’s current energy use, helping homeowners understand where energy savings can be made and improving the overall reliability of the certificate.