The Default Data Trap
hocking number of commercial EPCs in the UK are “default-heavy.” When an assessor cannot see the insulation or identify the exact model of a boiler, the software forces them to choose a “worst-case scenario” default value. This often results in a rating that is one or even two grades lower than reality. This article explores how “evidence-based” auditing can unlock a better EPC rating without spending a penny on hardware.
The ‘Default’ Problem in SBEM
Many commercial EPCs are inaccurate because assessors use “default values” when technical data is missing. By providing Operation & Maintenance (O&M) manuals, lighting specifications, and insulation records, landlords can replace these worst-case defaults with actual performance data, often improving the rating by a full grade.
2. The Importance of the O&M Manual
The O&M (Operation and Maintenance) manual is the EPC assessor’s best friend. We detail exactly which documents you need to dig out of the archives—specifically glazing U-values and HVAC seasonal efficiency ratings (SEER/SCOP).
3. Destructive vs. Non-Destructive Evidence
If you don’t have the paperwork, how do you prove the insulation is there? We look at the use of borescope inspections and thermal imaging as a way to provide “visual evidence” to the accreditation body.
4. The ‘Level 4’ vs ‘Level 5’ Distinction
Most EPCs are done at Level 3 or 4. For complex buildings with atria or innovative ventilation, a Level 5 Dynamic Simulation Model (DSM) is required. We explain why the extra cost of a DSM assessment is an investment that pays for itself in “avoided retrofit costs.”
5. Conclusion
Before committing to an expensive heat pump or window replacement, ensure your current EPC is based on facts, not assumptions. A data-driven audit is the first step in any energy strategy.
