Newly built homes are expected to be highly energy-efficient—but many owners are surprised when their EPC rating comes back unexpectedly low. Even with modern designs and building certifications, hidden construction problems can quietly drag down your score. If this has happened to you, getting a professional review from our EPC Assessors in London can help uncover what went wrong:
👉 https://epcrate.co.uk/services-epc-assessors-london/

Below are the most common reasons new builds fail to meet EPC expectations—and what you can do to fix them.

1. Poorly Installed Insulation (Even If Materials Are High-Grade)

Builders may use modern insulation materials, but poor installation can greatly reduce their effectiveness. Gaps, compression, and missed sections around lofts, floors, and wall joints create cold bridges that reduce thermal performance and lower your EPC score.

If you suspect incorrect installation, you can easily book a detailed EPC assessment here:
👉 https://epcrate.co.uk/booking/

2. Air Leakage Due to Incomplete Sealing

New builds should pass airtightness tests, but hidden gaps around pipes, window frames, and door fittings can cause heat loss. This makes your heating system work harder and reduces your EPC rating.

For expert support, check our About Us page to understand how our team ensures accurate results:
👉 https://epcrate.co.uk/about-us-epc-company-london/

3. Inefficient Heating System Setup

Sometimes the heating system is modern and efficient—but incorrectly configured. Common issues:

  • Poor radiator balancing

  • Incorrect boiler temperature settings

  • Weak zoning control

  • Heat pump miscalibration

These inefficiencies force higher energy use, dragging down your EPC rating.

If you need guidance on pricing for an updated assessment, see:
👉 https://epcrate.co.uk/pricing/

4. Poor-Quality or Incorrectly Installed Windows

Not all double glazing performs equally.
Issues like:

  • Low-performance glazing

  • Failed window seals

  • Poor frame fitting

…can significantly increase heat loss and decrease your EPC score.

5. Ventilation Systems Removing Too Much Warm Air

Modern new builds often rely on mechanical ventilation. When incorrectly installed, they may extract warm air excessively, causing heat loss and reducing energy efficiency.

A detailed assessment can confirm if this is affecting your rating.
Book here:
👉 https://epcrate.co.uk/booking/

6. Incorrect or Incomplete SAP Data Submitted

Sometimes the issue isn’t the construction—it’s the data.

Missing certificates or inaccurate figures in the SAP calculation can default your rating to worst-case estimates. This alone can drop a new build from a B to a C rating.

Our qualified assessors can correct and resubmit accurate data:
👉 https://epcrate.co.uk/services-epc-assessors-london/

7. Builders Using Minimum-Standard Materials

Many developers follow the bare minimum required by building regulations. Minimum-standard insulation, glazing, and heating equipment often translate into a modest EPC score, even if the home is technically compliant.

To discuss improvement ideas for your property, feel free to contact us directly:
👉 https://epcrate.co.uk/contact-us-epc-services-london/

Need to Improve Your New Build’s EPC?

If your new build received a lower EPC score than expected, we can help identify hidden construction issues, update incorrect SAP entries, and guide you on improvement steps.

Email :info@epcrate.co.uk

Phone:020 34884142