IGEM response to Home Energy Model: Energy Performance Certificates consultation

IGEM welcomes the opportunity to respond to the consultation on the future Energy Performance Certificate (EPC) methodology.

We support the aim of creating a more accurate and meaningful metric for consumers and policymakers. However, we are concerned that several elements of the proposed Heating System Metric risk pre-determining outcomes in favour of specific technologies rather than reflecting the real emissions performance of homes. A technology-agnostic, evidence-based framework is essential to ensure consumers are supported to make practical, fair, and cost-effective choices during the transition to net zero.

Our response to this consultation focuses on questions nine and 11, as outlined below.

Question 9: Do you agree with our proposal on the design and methodology for the Heating System metric? 

Disagree

EPC scoring should reflect actual carbon performance, not technology categories:

Preventing any home with a fossil-fuel component from achieving a C rating or above shifts the EPC from an emissions-based tool to a technology classification system. This approach ignores the fact that the carbon outcomes of heating systems depend on:

• The carbon intensity of the energy source.
• The way the system is operated.
• The efficiency of the appliances involved.
• The ability to integrate low-carbon gases now and in the future.

For example, the assumption that all fossil-fuel linked systems are inherently high-carbon does not hold when green gases (many of which are carbon-neutral or have the capacity to be carbon-negative in the future) are used to supply homes. Evidence shows biomethane already contributes significantly to UK energy supply and could grow to 120 TWh by 2050¹.

An EPC system rooted in measured or dynamically modelled carbon performance would avoid unintended outcomes and better reflect actual household emissions.

Hybrid heating systems deliver measurable decarbonisation and system benefits

The proposed cap preventing hybrid systems from scoring above a D rating does not reflect the real-world performance of these solutions. Evidence demonstrates that hybrid systems:

• Can reduce gas consumption by up to 80%², delivering immediate and substantial emissions reductions. 
• Provide the lowest-cost, clean-heat routes for the 30-47% low-efficiency homes through bio-hybrid configurations³. 
• Avoid unnecessary deep-retrofit requirements, supporting households with limited savings.
• Align with the long-term pathway for green gases, maintaining future compatibility.

Hybrids also provide important whole system advantages, such as:

• Reduced peak electricity demand through fuel-switching at constrained times.
• Deferred or avoided electricity network reinforcement.
• Reduced consumer exposure to peak electricity prices, particularly when paired with flexible tariffs.

A methodology that caps hybrid performance irrespective of real emissions risks discouraging a low-regret solution that is already delivering meaningful carbon reduction.

Consumer impact and fairness must be central considerations

The proposed approach places significant expectations on households to undertake costly upgrades. Evidence shows:

• One in six (16%) UK adults have no savings and 39% of UK adults have £1,000 or less in savings⁴, making high-cost installations financially unachievable for many.
• The average cost of installing an Air Source Heat Pump is ~£13,000⁵, and significant building fabric upgrade costs may also be incurred. 
• Hybrid systems allow 80% electrification of heat demand without making existing infrastructure redundant. 

Maintaining affordable, scalable pathways is critical to securing public support and ensuring the transition does not disproportionately affect lower-income households or those in hard-to-treat homes.
 

Green-gas options should be integrated into EPC scoring

Green gases, including biomethane, provide a credible, scalable route to heat decarbonisation without major disruption. Incorporating certified green gas tariffs into the EPC methodology would:

• Accurately reflect real emissions.
• Reward consumers who opt for low-carbon energy supplies.
• Prevent the EPC system from unintentionally steering households into more expensive pathways.
• Recognise the value of existing gas infrastructure that can be decarbonised at scale.

The current proposals treat all gas use as inherently high-carbon, which is inconsistent with the evidence base on sustainable gases and the whole-systems approach adopted by NESO. 

Question 11: What is your view on the option of reserving the highest scores of A/B for electric cooking appliances?   

Disagree

Limiting A/B ratings exclusively to electric cooking is disproportionate

Allocating the highest bands solely to electric cooking appliances overstates their importance within household energy demand, which is typically less than 10% even in efficient homes. This approach risks:
 

• Distorting the EPC by over-weighting a low-impact area.
• Creating unnecessary cost burdens when kitchens are replaced, such as re-wiring.
• Penalising households using green gas cooking, which can achieve low carbon, carbon neutral, or carbon negative emissions.
• Narrowing consumer choice without delivering meaningful carbon benefits.

A more appropriate approach would assess cooking emissions based on the carbon intensity of the energy used, not the technology type.

In addition to these concerns, restricting the highest EPC bands exclusively to electric cooking appliances may create unintended consequences for certain groups of consumers. Such as, individuals with pacemakers are advised to use precautions if using an induction hob due to electromagnetic interference risks (staying 2ft away from the stove top) and to potentially consider alternatives⁶. Designing EPC scoring in a way that implicitly favours induction cooking could therefore disadvantage households who cannot safely use these appliances for medical reasons. A proportionate methodology should ensure that consumers are not penalised for avoiding technologies that are clinically unsuitable for them.

Recommendations

To support a fair, affordable and evidence-based transition, we recommend that DESNZ:

• Adopts a performance-based, technology-neutral EPC methodology rooted in measured or dynamically modelled carbon outcomes.
• Removes blanket rating caps for hybrid systems, instead assessing their actual emissions and system value.
• Integrates green-gas pathways into all relevant elements of the EPC methodology.
• Avoids over-weighting cooking appliances within the scoring system.
• Ensures whole-system impacts, including peak-shaving and infrastructure cost-avoidance, are reflected in the Heating System Metric.

We strongly support Government efforts to modernise EPCs and make them more reflective of real-world performance. Introducing a methodology that captures genuine emissions, incorporates the role of green gases and recognises the immediate and long-term value of hybrid heating will enable a more balanced and fair transition for households across the UK.

Sources

1. Green Gas Taskforce: A Green Gas Future
2. Cadent: The scope for using hybrid systems in home heating: Recommendations for hybrid heating 
3. Green Gas Taskforce: Green Gas Homes Bio-Hybrids: A Clean Heat Solution
4. money.co.uk: UK Savings Statistics 2025 
5. UK Government: RAF052/2223: Evaluation of the Boiler Upgrade Scheme 
6. nhs.uk: Pacemaker implantation