Even modern homes—built with updated materials and considered energy efficient—often suffer from hidden heat leaks that significantly reduce their Energy Performance Certificate (EPC) score. Homeowners are frequently surprised when an EPC assessment reveals energy inefficiencies they didn’t expect. Understanding these issues can help you boost your rating, lower energy bills, and prepare for future regulatory requirements.

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1. Poorly Insulated Loft Hatches

Most homeowners insulate their lofts, but forget the loft hatch itself.
A thin, unsealed hatch becomes a major escape point for warm air—especially in winter.
During an EPC inspection, assessors often see:

  • No insulation on the hatch

  • Gaps around the frame

  • Warped or ill-fitting doors

➡️ A simple fix like a draught strip or insulated board can add points to your EPC.

2. Hidden Draughts Around Windows and Doors

Modern homes often have double-glazing, but small installation flaws still allow heat leakage.

Unexpected gaps appear due to:

  • Worn-out seals

  • Poor installation alignment

  • Settlement of the building

These gaps aren’t always visible—but they show up clearly during an EPC blower door test or thermal scan.

To book a professional EPC inspection that identifies these issues, visit our Booking Page.

3. Uninsulated Pipework in Newer Homes

Many modern-build properties have high-efficiency boilers but surprisingly uninsulated pipes in utility rooms, lofts, or under floors.

This can cause:

  • Significant heat loss

  • Lower hot-water efficiency

  • Reduced overall EPC rating

Pipe lagging is one of the most cost-effective fixes.

4. Thermal Bridging in Walls and Corners

Even when walls are insulated, heat can escape through structural junctions called thermal bridges.
These are common in modern homes with:

  • Steel beams

  • Unsupported corners

  • Balcony designs

  • Extended brickwork

Thermal bridging is difficult to identify without specialist tools, so it often surprises homeowners during an EPC assessment.

Learn more about what our assessors check on our Services – EPC Assessors London page.

5. Ventilation Leaks Behind Built-In Furniture

Modern homes often have built-in wardrobes or wall-fitted cabinets.
Behind these fixtures, there can be:

  • Unsealed gaps

  • Missing insulation

  • Cold air pathways to external walls

Because these areas stay hidden, they create unexpected heat leaks that reduce EPC performance.

6. Recessed Lighting That Breaks the Insulation Barrier

Downlights are stylish, but when improperly installed, they cut through insulation layers in ceilings—creating small but numerous heat leaks.

EPC assessors often find:

  • Gaps around lighting fixtures

  • Missing insulation around the casing

  • Accumulated air leakage from multiple fittings

LED fire-rated downlights with insulation covers help solve the issue.

7. Uninsulated Floors in Modern Extensions

Many modern extensions skip floor insulation if the structure didn’t originally require it.
However, EPC testing reveals:

  • Cold floors

  • Significant downward heat loss

  • Reduced thermal performance of the whole property

Adding insulated underlays or insulated boards can restore efficiency.

8. Mechanical Ventilation Heat Loss

Homes with mechanical ventilation systems (like MVHR or extractor fans) may still lose heat if:

  • Ducting isn’t insulated

  • Backdraft shutters are faulty

  • The system is incorrectly balanced

Even the latest build systems can underperform if not installed correctly.

Why Identifying Heat Leaks Matters

Fixing hidden leaks helps:

  • Improve EPC rating

  • Reduce energy bills

  • Increase property value

  • Meet rental compliance rules

  • Create a more comfortable living environment

If you’re comparing costs, view our transparent EPC prices on our Pricing Page.

Book a Professional EPC Assessment Today

Don’t let hidden heat leaks lower your EPC score.
Our certified EPC assessors use advanced tools to uncover energy inefficiencies that aren’t visible to the eye.

👉 Book your EPC with us today through our Online Booking Page.

Have questions? Reach out via our Contact Us page — we’re here to help.

Contact Us – EPCrate London

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