Air source heat pumps (ASHPs) are becoming a popular alternative to traditional heating systems in UK homes, especially for those seeking to lower carbon emissions and future-proof their property. However, many homeowners are surprised when installing this eco-friendly technology doesn’t automatically lead to a better Energy Performance Certificate (EPC) rating. So, why doesn’t your EPC always improve with a new air source heat pump?
Understanding EPC Ratings
An Energy Performance Certificate assesses a property’s energy efficiency on a scale from A (most efficient) to G (least efficient). The rating is calculated using factors like:
Insulation levels
Heating system efficiency
Construction type
Energy sources used
Lighting and ventilation
Why an ASHP May Not Improve Your EPC
Despite being a renewable technology, air source heat pumps can sometimes reduce your EPC score or offer marginal improvements. Here’s why:
1. Electricity Costs More Than Gas
EPCs are based on the cost to heat and run a home, not just carbon output. ASHPs use electricity, which is more expensive per unit than gas. This can result in a lower cost-efficiency score, even if carbon emissions are reduced.
2. Poor Installation and Setup
If your ASHP isn’t correctly sized, installed, or integrated with existing heating systems, it may underperform, making your home less efficient in practice.
3. Lack of Supporting Insulation
Heat pumps work best in well-insulated homes. If your property lacks adequate loft, floor, or wall insulation, the EPC may reflect wasted energy, offsetting the benefit of the ASHP.
4. SAP Calculation Limitations
The Standard Assessment Procedure (SAP) used for EPCs can be slow to recognise the real-world efficiency gains of newer technologies, especially when data is limited or defaults are applied.
How to Maximise EPC Improvement with an ASHP
Upgrade insulation before or alongside installing a heat pump.
Ensure the system is MCS-certified and installed by professionals.
Install smart heating controls to optimise usage.
Combine with solar PV panels to reduce electricity costs.
Need Help with an EPC in London?
At Urgent EPC, we provide:
Certified Assessors who understand the nuances of renewable technologies
Expert advice to help you improve your rating effectively
Contact Us
📞 Call: +44 7741 812 864
📧 Email: info@samedayepc.co.uk
