Energy
EPC ratings in London, explained.
How the rating is worked out, what actually moves it, and what the coming minimum standard means for a rented property.
What improves an EPC rating most?
The biggest single improvement for most London properties is a modern A-rated condensing boiler. A boiler replacement alone can move a property from E to D or D to C. Other high-impact improvements include:
- Loft insulation: One of the cheapest improvements with a high SAP score impact. 270mm of mineral wool insulation is current standard.
- Cavity wall insulation: Effective for 1930s–1990s construction with unfilled cavities. Solid-wall Victorian terraces require external or internal wall insulation.
- Double glazing: Replacing single-glazed windows with double glazing has a moderate impact on the rating.
- Heating controls: Adding a programmer, room thermostat and TRVs improves the SAP assessment of the heating system.
- Low-energy lighting: Replacing all bulbs with LED adds a small number of points, inexpensive and worth doing.
Getting an EPC in London
An EPC assessment takes around 45–60 minutes. The assessor visits the property, takes measurements and records the construction type, heating system, insulation levels and glazing. The certificate is produced immediately after the visit and registered on the government database the same day.