How Is an Energy Performance Certificate Calculated?

When selling, renting, or building a property in the UK, one essential document is the Energy Performance Certificate (EPC). But how is an EPC calculated? At Urgent EPC, we break down the process to help property owners across the UK — especially in London — understand what goes into assessing their energy performance.

What Is an EPC?

An Energy Performance Certificate provides an efficiency rating from A (most efficient) to G (least efficient) based on your property’s energy usage and typical energy costs. This rating is calculated by an accredited Domestic Energy Assessor (DEA) following a strict methodology.

Learn more about our commitment to transparency and quick EPC assessments on our About Us page.

Step-by-Step EPC Calculation Process

1. On-Site Assessment

A certified assessor will visit your property to examine:

• Construction materials and insulation

• Heating system type and controls

• Windows (single, double, or triple-glazed)

• Roof, walls, and flooring

• Renewable energy sources (e.g., solar panels)

This is part of the Residential EPC service we offer to homeowners, landlords, and letting agents.

2. Standard Assessment Procedure (SAP)

The data collected during the inspection is entered into the UK government’s Standard Assessment Procedure (SAP) software. This determines the property’s theoretical energy consumption and environmental impact.

Factors considered include:

• Building fabric (thermal efficiency)

• Heating system performance

• Hot water and lighting systems

• Air leakage and ventilation

3. Generating the EPC

Once calculations are complete, the EPC will:

• Display the current energy rating and potential rating if improvements are made

• Estimate annual energy use and carbon dioxide emissions

• Suggest cost-effective measures for better efficiency

4. Delivery and Registration

The EPC is then registered on the official EPC Register and emailed to the property owner or landlord. Need it today? Take advantage of our Same-Day EPC service for fast, compliant results.

Why Accurate EPC Calculations Matter

Getting an EPC isn’t just about legal compliance — it can also:

• Improve resale or rental value

• Reduce energy bills through efficiency upgrades

• Identify carbon-saving opportunities

Got Questions? Let’s Talk!

If you’re unsure about your EPC rating, property eligibility, or how to book an assessment, visit our Contact Us page. Our dedicated team is ready to help.

Get Your EPC Fast with Urgent EPC
We make the EPC process simple, fast, and affordable across London and beyond. Whether you need a standard Residential EPC or Same-Day EPC, our assessors ensure full compliance and accuracy.

✅ Certified Assessors
✅ Quick Turnaround
✅ 100% Government Compliant

📞 Ready to book or need expert advice? Visit our Contact Page or call us directly.