When homeowners and landlords think about improving their Energy Performance Certificate (EPC) rating, major upgrades like boilers, insulation, and double glazing often come to mind. However, one small and cost-effective measure that is frequently overlooked is draught-proofing.
Draughts not only make your home uncomfortable—they also allow unnecessary heat loss, which directly impacts your EPC score. Our experienced EPC Assessors in London often see properties losing valuable points simply because gaps around windows, doors, and floors were not addressed:
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1. Why Draught-Proofing Matters for EPCs
EPC assessments evaluate how efficiently a property retains and uses energy. Air leakage through unsealed gaps allows heat to escape, forcing heating systems to work harder.
Increased heat loss reduces the assumed efficiency of the building fabric.
Even small gaps can negatively affect EPC calculations.
Draughts are particularly critical in older properties with timber frames or single-glazed windows.
Sealing gaps and draught-proofing effectively improves energy efficiency, comfort, and your EPC rating.
2. Common Draught Sources
Assessors look for several common sources of draughts during inspections:
Doors: Gaps around the frame, letterboxes, and keyholes
Windows: Poor seals, sash movement, or warped frames
Floorboards: Especially in older homes, gaps under skirting boards
Lofts and Attics: Poorly sealed hatches or attic doors
Chimneys and Flues: Unused fireplaces or vents can allow heat to escape
Addressing these areas often yields quick and cost-effective EPC gains.
3. Effective Draught-Proofing Solutions
a) Doors
Install door sweeps to seal the bottom gap
Fit draught excluders around frames
Cover letterboxes with brushes or flaps
b) Windows
Use self-adhesive seals for sash or casement windows
Repair or replace damaged seals
Ensure secondary glazing is properly fitted
c) Floors and Skirting
Fit flexible gap seals along skirting boards
Check for gaps around floorboards and thresholds
d) Chimneys and Flues
Install chimney balloons in unused fireplaces
Ensure vent covers are secure
These measures are low-cost and often DIY-friendly, yet they can significantly enhance EPC performance.
4. Draught-Proofing as Part of a Broader EPC Strategy
While draught-proofing alone will not transform your EPC rating, it is a critical complement to other improvements:
Insulation: Draughts can reduce the effectiveness of loft or cavity wall insulation
Heating Efficiency: Proper sealing reduces unnecessary heating demand
Lighting and Controls: Energy savings from draught-proofing multiply with other upgrades
Together, these measures contribute to maximising points during EPC assessment.
5. Cost vs Benefit
Draught-proofing is one of the most cost-effective EPC improvements:
Most materials cost under £50–£100
DIY installation is straightforward
Immediate comfort improvement
Helps maintain EPC points for years with minimal maintenance
By investing in small measures, homeowners often achieve more EPC points per pound spent than major upgrades alone.
6. When to Re-Assess Your EPC
After implementing draught-proofing:
Ensure all gaps are sealed and visible
Gather any supporting documentation (if using professional installers)
Schedule an EPC re-assessment to capture the improved rating
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7. Key Takeaways
Draught-proofing addresses unnecessary heat loss, improving energy efficiency and EPC scores.
Common areas include doors, windows, floors, loft hatches, and chimneys.
Solutions are affordable, quick, and often DIY-friendly.
Draught-proofing enhances the effectiveness of other EPC improvements, like insulation and heating controls.
Proper preparation and documentation ensure improvements are credited during assessment.