Energy Performance Certificates (EPCs) measure a building’s energy efficiency, providing crucial guidance for owners, tenants, and policymakers. In the quest for sustainable construction, Phase-Change Materials (PCMs) have been promoted as a solution to improve thermal performance. But the question remains: do PCMs genuinely impact EPC ratings, or is their effect overstated?
What Are Phase-Change Materials (PCMs)?
Phase-Change Materials are substances that absorb or release heat as they change between solid and liquid states. They act as thermal buffers, stabilizing indoor temperatures by:
Storing excess heat during the day.
Releasing heat when indoor temperatures drop.
Common examples include paraffin waxes, salt hydrates, and bio-based PCMs embedded in walls, ceilings, or flooring. For more information on energy-efficient building materials, visit our About Us page.
How PCMs Could Affect EPC Performance
PCMs influence a building’s energy demand in two main ways:
Reducing Heating and Cooling Loads – By absorbing heat during peak periods, PCMs can reduce the need for active heating or cooling, potentially lowering energy consumption.
Stabilizing Indoor Temperature – A more stable indoor environment may lead to lower energy use for HVAC systems, which EPC calculations may recognize.
However, the impact of PCMs on EPC ratings depends on several factors:
Integration Method – How PCMs are incorporated into building fabric affects performance.
Building Type – Residential, commercial, or high-occupancy buildings respond differently.
Local Climate – The energy-saving potential of PCMs is more pronounced in climates with high temperature swings.
Learn more about booking an assessment to check EPC performance here.
Fact or Fiction? Evaluating the Evidence
While PCMs can improve thermal comfort and reduce peak energy demand, their effect on EPC ratings is not always straightforward:
EPC assessments rely on standardized models, which may not fully account for PCM effects unless detailed simulations are conducted.
Over-reliance on PCMs without proper design may not result in measurable EPC improvements.
PCMs are more effective when combined with other energy-efficient strategies like high-performance insulation, smart controls, and optimized ventilation.
For expert EPC advice, see our EPC Assessors in London page.
Benefits of Using PCMs
Enhanced thermal comfort for occupants.
Potential reduction in heating and cooling energy demand.
Contribution to sustainable building practices.
Check our Pricing for assessment services.
Challenges and Considerations
Initial installation costs can be high.
Long-term performance depends on proper integration and material quality.
EPC impact may be limited if the assessment methodology does not include dynamic modeling of thermal storage.
Contact us for more information: Contact Us.
Conclusion
Phase-Change Materials can play a significant role in improving building thermal performance, but their effect on EPC ratings is context-dependent. They should be seen as part of an integrated energy strategy rather than a standalone solution for improving EPC scores.
