The Government is currently consulting on its new Future Homes Standard, which includes proposals to increase the energy efficiency requirements for new homes in 2020. Part of this includes an update to Part L of the Building Regulations, which is the section that relates to energy efficiency, and in particular the changes that will make heat pumps the go-to heating system for developers.
The Government has set out its proposals for new standards for new build homes in the UK, including low-carbon heating systems, triple glazing, building fabrics that limit heat-loss and onsite generation assets which would be mandatory after 2020.
These new measures shall contribute enormously towards plans to ban fossil fuel heating systems by 2025, ultimately aiming to reduce the carbon intensity of new build homes by 80%. Heat Pumps and other carbon-saving methods shall significantly support these changes for improving new build homes in the UK.
Carbon Emissions Factors for Fuels
As part of these proposals, there is a change which will have a huge impact on the choice of heating fuel for a new building. As things stand at the moment, the emission factors for the various fuel choices for a new heating system are based on out-of-date figures. This is because SAP (which stands for Standard Assessment Procedure and is calculation carried out on new buildings to determine how energy efficient they are) hasn’t been updated since 2012.
Since 2012, the UK electricity grid has undergone a huge transformation, with a significant increase in zero carbon sources of electricity such as wind and solar power. This is great news for heat pumps, which utilise electricity to convert stored solar energy in the ground or the air into useful heat energy in the home. The new standards proposed for 2020 will reflect this decarbonisation, whilst also removing certain advantageous factors for traditional fossil fuel sources, thus supporting the phase out of fossil fuel heating systems in new build dwellings.
Proposed carbon factors
The proposed (and current) carbon emission factors (in KG of CO2 per kWh primary energy) for each fuel are listed below:
Electricity – 0.233 (previously 0.519)
Mains Gas – 0.210 (previously 0.216)
Heating Oil – 0.298 (no change)
LPG – 0.241 (no change)
As these figures show, mains electricity has undergone a significant decarbonisation, and this is now going to be reflected in the Building Regulations. As soon as the changes come into force, the emissions produced by heat pumps in the SAP calculations will become more than 50% lower than they already are!
Heating System Efficiency
Obviously the emissions factor alone does not dictate the emissions for the building: this needs to be combined with the heat system efficiency to then calculation the design carbon emissions for a property. This is another area where heat pumps provide a significant advantage.
Traditional boilers utilise combustion, meaning that the input fuel is burned in order to provide the energy which is then used to heat the home. Typical efficiency levels for new buildings are around 90%, meaning about 90% of the input energy is converted into useful heat.
Heat pumps work in a completely different way, with no combustion. For ground source heat pumps, stored solar energy in the ground is moved into the home; for air source heat pumps, stored solar energy in the air is moved into the home. Not only is this safer, but it is also significantly more efficient, because heat energy is not being created, it is simply being moved from one place to another. All that heat pumps require is a small amount of electricity to operate the circulation pumps and compressor.
The ratio of useful heat supplied to the home, and the electricity consumed in doing so, is typically referred to as the Coefficient of Performance, or CoP. A typical CoP for a heat pump is between 3 and 4, meaning that 3 – 4 units of heat are provided to the home for every 1 unit of electricity consumed.
By combining the emission factors for the fuel, with the efficiency of the heat system, the SAP calculation thereby calculates the total carbon emissions from the property heating system.
Heat Pumps Are The Obvious Choice
These changes clearly the demonstrate the Government’s desire to move away from fossil fuel heating systems in new build homes, and move towards electrically-driven heat pump technology, which compliments a rapidly decarbonised electricity grid.
As things stand using the current Building Regulations, heat pumps still show lower carbon emissions than off-gas heating systems such as heating oil, LPG and direct electric heating, even with the significantly out-of-date emissions factors for electricity. Once these new Building Regulations become mandatory, heat pumps will become the obvious choice for all situations.
By choosing heat pumps, developers will find compliance with building regulations much easier. The lower electricity emission factors, which reflect the current performance of the electricity grid, mean that heat pumps will be the lowest carbon emission technology available for builders to choose from.