Many homeowners treat an Energy Performance Certificate (EPC) assessment as a simple box-ticking exercise. In reality, poor preparation is one of the biggest reasons properties receive lower-than-expected EPC ratings.
The good news? Most EPC mistakes are easy to avoid once you understand how EPC assessments work and what assessors actually look for. Our experienced EPC Assessors in London see the same preventable issues repeatedly—and correcting them often leads to immediate score improvements:
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1. Booking an EPC Without Preparing the Property
One of the most common mistakes homeowners make is booking an EPC assessment too early.
Many assume assessors will “advise what to fix” after the assessment. While recommendations are included, the EPC score is already locked in by then.
Better approach:
Prepare the property first
Make simple efficiency improvements
Then book the assessment
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2. Assuming Comfort Equals Efficiency
A warm home doesn’t automatically mean an energy-efficient one.
Common assumptions:
“The house heats up quickly”
“We rarely use much heating”
“Our bills seem reasonable”
EPCs are based on measured efficiency, not personal usage habits. A property can feel comfortable yet score poorly due to outdated systems or missing insulation.
3. Ignoring Insulation Gaps
Insulation is one of the most heavily weighted EPC factors, yet it’s often incomplete.
Frequent insulation-related mistakes:
Loft insulation below recommended depth
Missing cavity wall insulation
No insulation on hot water cylinders or pipes
Assuming insulation exists without checking
If insulation can’t be verified during assessment, it won’t be fully credited.
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4. Overlooking Heating Controls
Many homeowners focus on boilers but ignore controls, which EPCs value highly.
Common issues include:
No programmable thermostat
Missing thermostatic radiator valves (TRVs)
No zoning or room-based control
Adding basic controls is often cheaper than replacing a boiler and can still lift an EPC band.
5. Leaving Inefficient Lighting Installed
Lighting is a small but critical EPC component—especially when scores are close to a band threshold.
Mistakes include:
Leaving halogen or incandescent bulbs installed
Partial LED coverage only
Ignoring fixed external lighting
Switching to 100% LED lighting is one of the easiest EPC wins homeowners miss.
6. Failing to Gather Evidence of Improvements
EPC assessments rely on proof, not just claims.
Homeowners often forget:
Boiler installation certificates
Insulation invoices or guarantees
Manufacturer efficiency labels
Photos of hidden insulation
Without documentation, assessors must apply default assumptions, which usually lower the score.
7. Spending Money on Low-Impact Upgrades
Some upgrades look impressive but have little EPC impact.
Common low-return investments:
New kitchens or bathrooms
Energy-efficient appliances
Smart gadgets without heating integration
EPCs reward building fabric and heating efficiency first, not cosmetic upgrades.
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8. Ignoring Windows and Draughts
Windows and doors are often underestimated EPC contributors.
Mistakes include:
Assuming all double glazing performs well
Leaving draughts unsealed
Not installing secondary glazing where replacement isn’t possible
Even modest draught-proofing can prevent EPC underperformance.
9. Assuming Renewables Will “Fix” a Low EPC
Renewable energy systems help—but they don’t compensate for poor fundamentals.
Common misconception:
Installing solar panels alone guarantees a high EPC
Without good insulation and efficient heating, renewable systems deliver limited EPC benefit.
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10. Not Understanding EPC Band Thresholds
Many homeowners miss out on a higher EPC band by just one or two points.
Mistakes include:
Ignoring small improvements that could cross a threshold
Not checking how close the current score is to the next band
Booking assessment without pushing for the extra points
Simple changes like LED lighting or TRVs can often make the difference.
How to Avoid These EPC Mistakes
Before booking your EPC, take these steps:
Review your existing EPC report
Top up insulation where needed
Upgrade heating controls
Replace all lighting with LEDs
Seal draughts around windows and doors
Gather all documentation
Book the assessment only when ready
Conclusion
Most low EPC scores aren’t caused by major structural problems—they’re caused by avoidable preparation mistakes.
Key Takeaways
EPCs reward measurable efficiency, not comfort
Insulation and heating controls matter most
Evidence is critical for accurate scoring
Small, low-cost changes can prevent big score losses
Timing and preparation make all the difference
By avoiding these common EPC mistakes, homeowners can achieve a more accurate, higher EPC rating—protecting property value, improving marketability, and ensuring compliance.
Email :info@epcrate.co.uk
Phone:020 34884142
