Energy Performance Certificates (EPCs) are designed to measure how energy-efficient a property is. But ask anyone who’s done a thermal imaging survey and they’ll tell you: you can’t truly understand heat loss until you see it.
Thermal imaging—using infrared cameras to detect heat escape—offers visual proof of inefficiencies. Yet in the UK, it remains entirely optional and often excluded from EPC assessments.
Why isn’t thermal imaging part of the EPC process — and what’s the cost of that omission?
🌡️ What Is Thermal Imaging in Buildings?
Thermal imaging, or thermography, uses infrared cameras to map surface temperatures. It’s most commonly used to:
Detect heat leaks around windows, doors, roofs, and walls
Reveal missing or degraded insulation
Spot dampness, thermal bridging, and cold spots
Validate workmanship after retrofits or renovations
A thermal image shows problems that the naked eye and standard EPC methodology simply cannot detect.
📋 EPCs: A System Based on Assumptions
EPC ratings in the UK are derived from the SAP (Standard Assessment Procedure) or its simplified cousin RdSAP for existing homes.
But here’s the problem:
Assessors don’t open walls or inspect behind cladding
They can’t confirm insulation quality—only its presumed presence
Measurements are based on visual inspections and data entry, not empirical testing
“If it’s marked on the plans, it’s assumed to exist. Even if the heat says otherwise.”
That’s where thermal imaging offers a reality check.
🧪 What Thermal Imaging Reveals That EPCs Miss
| Aspect | Standard EPC | Thermal Imaging |
|---|---|---|
| Missing insulation | Assumed present | Visibly exposed |
| Air leakage around windows/doors | Not detected | Highlighted in red |
| Cold bridges (e.g. lintels, floor joints) | Not accounted for | Clearly seen |
| Workmanship flaws (post-retrofit) | Ignored | Verified on camera |
| Radiator positioning, pipe losses | Not included | Mapped in detail |
In short, thermal imaging makes theoretical ratings accountable to real-world performance.
🧩 Why Isn’t Thermal Imaging Part of the EPC Process?
1. Time and Cost
A standard EPC takes ~1 hour and costs £60–£120
Thermal imaging surveys require cool weather, prep, and calibrated tools
Surveys cost £200–£500 on average
2. Training and Equipment
Most domestic EPC assessors are not trained thermographers
Proper thermal imaging requires expertise, interpretation, and certification
The government has not mandated it in RdSAP protocols
3. Inconsistent Conditions
Thermal scans require a temperature difference of at least 10°C between inside and outside
Timing, weather, and even furniture placement can affect results
“You can’t just point a thermal camera and guess. It needs context and experience.”
🔄 So Why Should It Be Standard?
Despite its challenges, including thermal imaging in EPC assessments could lead to:
✅ More Accurate EPC Ratings
Avoid false assumptions (e.g. cavity walls actually uninsulated)
Detect retrofit failures, botched installations, or moisture-induced energy loss
✅ Stronger Consumer Protection
Buyers, tenants, and landlords deserve to know what they’re paying for
Helps combat EPC fraud or negligent certifications
✅ Better Retrofit Outcomes
Targeted insulation or air-tightness upgrades based on real issues, not generic suggestions
Avoids unnecessary works, saving money and embodied carbon
🧰 Hybrid Approach: EPC + Optional Thermal Imaging Report
A practical compromise may be:
Keep EPCs as a baseline legal document
Offer thermal imaging as an add-on or retrofit validation tool
Include a “thermal verified” badge or appendix in EPC documents
Several private companies already offer this as a premium EPC service, with strong uptake in:
High-end properties
Retrofit projects
Landlords seeking MEES compliance
🔎 Case Study: EPC D Rated, But Thermally A+
A 1930s semi-detached house in Bristol was given a D-rated EPC despite new insulation and triple glazing. The homeowner was skeptical.
They commissioned a thermal survey and found:
No heat loss through walls or loft
Excellent window seals and door insulation
Small heat bleed only through the suspended timber floor
Conclusion? The EPC rating underrepresented real performance — and penalised the home for using a wood stove instead of a gas boiler.
🛠️ Policy Outlook: Will Thermal Imaging Ever Be Mandated?
As part of the UK’s net zero by 2050 roadmap, EPC reform is under review.
The government has acknowledged the need for:
More accurate EPCs
Post-retrofit verification
Digital integration and smart meter data
Thermal imaging may play a role, especially in:
PAS 2035-compliant retrofits
TrustMark-approved whole-house plans
Future MEES enforcement in PRS
However, cost and logistics remain hurdles.
🚪 Conclusion: Time to Look Through the Walls
The phrase “You can’t manage what you can’t see” holds especially true for energy performance. EPCs were never designed to measure invisible flaws — but thermal imaging can.
If the UK is serious about improving real energy efficiency, it’s time to consider:
Should thermal imaging be optional, or a new standard in EPC reporting?
Until then, homeowners and landlords looking for truth beyond the certificate would be wise to book a thermal survey — and finally see what their walls are hiding.
The EPC graph is just the beginning. When you know how to read between the lines, your report becomes more than a score—it becomes a blueprint for saving energy, reducing emissions, and increasing property value.
Ready to unlock the full story of your EPC?
📅 Book your expert EPC assessment today at EPCrate.co.uk.
