EPC for New Builds: Why Some New Homes Still Score Poorly?

Surprisingly, some new builds still score poorly, leaving homeowners and buyers scratching their heads.

Here’s why this happens, and what you can do to avoid a low rating in a new property.

1. EPCs Measure Energy Efficiency, Not Age

An Energy Performance Certificate (EPC) focuses on energy use, carbon emissions, and efficiency, not whether a building is brand new.

Even a freshly constructed home can score low if:

• Heating systems are inefficient

• Ventilation is poorly designed

• Renewable integration is missing

• Insulation or glazing doesn’t meet optimal SAP assumptions

2. Common Reasons New Builds Score Low

a) Heating System Inefficiency

• Small, cheap boilers or electric resistance systems are common in some new homes

• Poor zoning or controls reduce SAP efficiency scores

b) Renewable Technologies Are Absent

• Heat pumps, solar panels, and low-carbon energy systems are not always installed in new builds

• Lack of renewables can penalise SAP scoring

c) Thermal Bridging & Poor Detailing

• Gaps in insulation, thermal bridges around walls, floors, and roofs reduce efficiency

• Even with modern materials, poor workmanship can lower EPC points

d) Default SAP Assumptions

• EPC assessors often use default values when details are missing

• If the builder hasn’t provided certified system specifications, the property may be scored more conservatively

3. Why New Build EPCs Still Matter

Even though a home is new:

• Buyers consider EPC rating for running costs

• Mortgage lenders may flag low ratings

• Rental properties must meet MEES standards

A poor EPC can impact sale price, marketability, and future compliance.

4. How Developers Can Improve EPC Scores

Smart developers focus on:

1. Installing high-efficiency boilers or heat pumps

2. Including smart heating controls

3. Providing full documentation for assessors

4. Optimising insulation and reducing thermal bridging

5. Incorporating renewables where feasible

Proper planning ensures the new build achieves its expected EPC rating.

5. How Homeowners Should Respond

If you’ve bought a new build and your EPC is lower than expected:

• Review the report carefully

• Check for missing data or errors

• Consider targeted upgrades like controls or insulation

• Consult an accredited EPC Assessor in London for advice

You can book an assessment, review pricing, and learn about EPCrate on the About Us page.

Questions can also be addressed via the Contact Us page.

Final Thoughts

Even brand-new homes are not guaranteed high EPC ratings.

The difference comes down to:

• Heating and energy systems

• Insulation and workmanship

• Accurate documentation

• Use of low-carbon technologies

Understanding this helps homebuyers, developers, and landlords make smarter decisions, improve energy efficiency, and protect property value.

Those who ignore the shift will find EPCs becoming more expensive, more restrictive, and harder to fix later.