Electric heating can significantly impact the Energy Performance Certificate (EPC) rating of a property, often resulting in a lower score compared to homes using gas or other forms of heating. This is primarily due to the way energy consumption and efficiency are calculated in the EPC process and the higher cost associated with electricity as a fuel source.
1. Energy Cost Per Unit
One of the key reasons electric heating negatively impacts an EPC rating is the cost per unit of electricity compared to other fuels, especially gas. While electricity is generally considered a cleaner form of energy in terms of carbon emissions at the point of use, it is much more expensive than gas. EPCs are heavily weighted towards fuel costs, meaning properties that rely on electricity for heating, hot water, and even appliances tend to fare worse than those using cheaper fuels. Gas is currently the most common form of heating in the UK and, on average, costs around 4p to 5p per kilowatt-hour (kWh) compared to electricity, which can cost upwards of 17p per kWh. This stark difference in running costs is a major factor in why electric heating systems can lead to lower EPC scores.
2. Energy Efficiency Calculation
The EPC system calculates the energy efficiency of a property based on the standard assessment procedure (SAP). This considers the energy demand and fuel type for heating, hot water, and lighting. Electric heaters, such as panel heaters or storage heaters, are often less efficient at converting energy into usable heat than a gas boiler system, for instance. Many traditional electric heating systems lack the ability to modulate heat output efficiently or store heat, which results in higher consumption. Storage heaters, which are designed to charge up overnight when electricity is cheaper, can be inefficient in homes that are not well insulated, leading to excessive heat loss and more energy consumption during the day.
3. Grid Electricity’s Carbon Intensity
Although the UK electricity grid is decarbonising rapidly with increasing shares of renewable energy, the SAP methodology used in EPCs still considers the carbon intensity of grid electricity to be higher than that of gas. This means that properties with electric heating systems, particularly older or less efficient ones, are penalised because they are perceived as contributing more to carbon emissions. The EPC framework, while intended to encourage greener building practices, doesn’t fully reflect the potential of modern electric heating technologies such as heat pumps, which are far more efficient and environmentally friendly than older electric systems.
4. Lack of Insulation and Modern Heating Systems
Homes using electric heating often perform poorly on EPCs because they tend to be older buildings that lack sufficient insulation. Without proper insulation, electric heaters struggle to maintain consistent warmth, leading to higher energy usage and, subsequently, higher running costs. Furthermore, many electric heating systems in these properties are outdated, such as electric panel heaters or night storage heaters, which are not as efficient as modern alternatives like heat pumps. Properties that haven’t adopted newer electric heating technologies are therefore at a disadvantage.
5. Changing Market Perception
It is worth noting that EPC methodology and the energy landscape in the UK are evolving. Electric heating may not always result in a low EPC score, especially as the national grid continues to decarbonise and innovative technologies like heat pumps become more widespread. However, for the time being, EPC assessments remain highly cost-centric, and as long as electricity remains a more expensive option than gas, properties with electric heating are likely to continue scoring poorly.
Conclusion
In summary, electric heating negatively affects EPC scores due to the high cost of electricity per unit, the perceived inefficiency of traditional electric systems, and the outdated carbon intensity calculations of grid electricity. While this may change as the energy grid shifts towards renewables and new technologies emerge, for now, properties with electric heating remain at a disadvantage under the current EPC assessment framework. For homeowners or landlords, the key to improving EPC scores lies in upgrading to more efficient electric heating systems and improving insulation to reduce overall energy demand.