What is the future of Heat? Part 1: heat pumps
Posted by Brychan Williams on 26 July 2019 at 4:36 pm
The Government’s advisor the Committee on Climate Change recommended back in March this year that gas heating should be banned in the UK for new homes as of 2025 to help meet climate change obligations. Currently gas is the primary source of heating for around 85% of UK homes. As is evident, currently homes within the UK rely heavily on gas for heating.
Therefore, what possible options are there available that can replace gas as the main source of heating within the UK? Further for those who want to change from their gas based systems, what can they do in order to reduce their carbon footprint?
Currently, it is difficult to see exactly what the future of heat will be within the UK. Of the options available, some systems are too expensive, some don’t suit particular households and other forms of systems such as a hydrogen based heating system aren’t fully developed or adequately means tested yet. What does appear likely, in line with the Government’s ‘Clean Growth Strategy’, that the future of heating will be largely electric based.
In part 1 of this blog we will look at air source heat pump and ground source heat pump systems and analyse the role that they could potentially play in the future of UK heating.
Air source heat pumps and ground source heat pumps
Heat pumps operate in a similar way to refrigerators in the sense that they capture heat from outside a property, either from the air, ground or nearby water and concentrate it for use inside.
- Greener than gas: Heat pumps operate at efficiencies of around 250-400% depending on the type and season, which means for every unit of electricity used, 2.5-4 units of thermal energy is created. This energy is also created without releasing harmful gasses into the atmosphere locally; as long as the electricity used to run the system comes from a renewable source. In Q4 of 2018 the UK’s electricity mix was made up of 37.1% renewables, dramatically improving the ‘green’ benefits of heat pumps. The grid is set to become increasingly de-carbonised over the next few years and therefore these systems will only become more renewable over time.
- Renewable Heat Incentive (RHI): The government offers financial support for qualifying heat pump systems. As of 2014 the government has put in place the RHI. It provides financial support for the domestic owner of heating system for seven years. This support comes in the form of quarterly payments over seven years. The amount you can earn depends on several different factors. You can estimate how much money you could receive through the RHI scheme by using the Department for Business, Energy and Industrial Strategy’s calculator. For air source heat pumps you could potentially receive up to £9,100 and for a ground source system you can receive up to £27,000.
- Savings on fuel bills can be are significant: Ground Source heat pump systems are estimated to be around 26% cheaper than the savings that can be made with a new gas boiler (factoring in running costs). However, these savings are dependent on a number of factors therefore it is quite difficult to accurately calculate total savings and they are likely to be different for each household.
- Low Maintenance: Once a year some details of the system need to be checked, while it is advisable to enter into a servicing contract some basic details could easily be checked by yourself. Installers should give you details about what to check and they will usually guarantee as part of an instalment guarantee that they will come round every 3-5 years to check the system.
- Heat pumps are expensive to install but you can recover some of the capital costs through the RHI payments over 7 years. However, for those who are on low incomes or cannot afford to pay between £6,000- £18,000 to install these systems, they unfortunately won’t be an option.
- Heat pumps rely very heavily on electricity to operate. If the electricity supplied to power heat pumps comes from conventional or ‘brown’ sources, this reduces the environmental benefits of a heat pump. However, they are a perfect fit to go alongside a solar electric panel system. If coupled together with sufficient solar PV, heat pumps could potentially make your home a zero net energy home during the summer. This can occur when your solar panel system is generating at optimum conditions.
- During times of cold weather, heat pumps can experience some issues. Full heat efficiency cannot always be achieved during really cold weather and the back-up heating within the heat pump might be called into operation. Installations should be carried out only by contractors who are registered with the Micro-Generation Certification Scheme.
- Heat pumps are not suitable for all types of buildings. They only really work well in well insulated homes free from draughts. Therefore, for energy inefficient homes these are generally not suitable.
- Heat Pumps tend to work most efficiently when the hot water they produce for space heating is delivered at a lower temperature and over a consistent period of time. For this reason, it is important that occupants understand how to run and control their heating system to get the best performance. In addition, the heat distribution system must be carefully designed be it underfloor heating, special fan coil radiators or traditional radiators. Standard type radiators will invariably need to be oversized to take account of the lower water circulation temperatures.
We asked Paul Ciniglio owner of an Air Source Heat Pump in his ‘SuperHome’ about his experience. he said “I have been very pleased with my Air Source Heat Pump since I installed it in my home in 2009. My house is located off the gas network in a rural location so it was a very good fit with heat pump technology. I made sure that I upgraded the thermal performance of my existing home with new insulation and reducing unwanted air leakage before the installation. I have been very impressed with the reliability of my heat pump, it hasn’t failed me in a decade. My thermal comfort improved post retrofit and my heating and hot water running costs have been affordable.”
From all of the above, it looks like heat pumps could be the heating systems of the future. Making heat pumps the norm for new builds would lead to demand going up and the price going down. However, as 85% of households currently rely on gas for heating, substantial reinforcement of the national electricity grid would need to be undertaken to support the eletrical demand. Further, a lot of these households will not be energy efficient enough or adequately insulated for heat pump systems. It is also unlikely the majority of households will be able to afford the initial costs of these systems.
This leaves a gap however. How can we replace gas? Can we make heating more sustainable whilst at the same time make it affordable for consumers? These are questions that will need to be answered if the UK is set to meet its current target of becoming a net-zero carbon economy by 2050. The UK government has yet set out how it is going to achieve this and has not explained what will replace gas.
In part two of this blog series we will explore some of the other options.
If you have a question about anything in the above blog, please ask it in the comments section below.
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