If you’re looking for a sustainable way to heat your home and its hot water system this year, reduce your carbon emissions, and increase your home’s energy efficiency, a ground source heat pump (GSHP) is an intelligent choice. With financial incentives in 2019/20 and reduced energy bills also on offer, here’s everything you need to know about a ground source heat pump…
Simply put, a ground source heat pump draws heat from the earth and transfers it into functional energy for heating and hot water systems – in domestic and commercial properties.
A ground source heat pump is an energy efficient, renewable source of heating for your home – which is a great choice if you’re not on the mains grid system and need to use alternative energy sources. Furthermore, if you want a cleaner and greener source of energy, a GSHP may be the answer to reducing your carbon footprint whilst making a sensible long-term investment in your home.
Even in our temperate climate, this is a highly efficient system. The sun’s energy heats the earth and rock below ground level, which stays at a fairly constant temperature all year round. Although we normally require more heating for our homes during the evening and in the winter – the opposite times to when the sun is at its peak – heat pumps use ambient low-level heat and transfer it into usable heat for our homes and hot water. This is why a ground source heat pump is such a great solution for UK homes.
How a ground source heat pump works is really quite simple. It converts the stored heat energy from earth and rock under the ground’s surface into higher temperatures, which can be used for space and water heating, through a system of pipes and heat exchangers.
A GSHP can be classed as a horizontal system or a vertical system, based on whether it utilises shallow trenches (horizontal) or a deep borehole (vertical). Which option you choose will likely come down to the space you have available and your budget for the work.
Whichever system you choose, loops of pipe are installed underground, either along the trenches or down the borehole. Through these pipes runs a solution of heat transfer fluid (a mixture of water and antifreeze) that absorbs the low-level heat from the surrounding earth and rock.
The warmed solution is transferred through a heat exchanger inside the pump into a refrigerant circuit, which when compressed, raises the temperature to a much higher level. This usable heat is then transferred through another heat exchanger into the heating and/or hot water system of your home. The cooled liquid continues through the pump and back out into the pipe loops, ready to be warmed again – thus providing a constant flow of energy.
The heat pump itself sits above ground and is often around the same size as a small refrigerator. It will require a modest amount of space – if you’re building a new property or have existing space, we recommend a plant room approximately 1m x 3m in size to comfortably accommodate your unit and hot water cylinder, and allow space around it for maintenance and servicing work. This is often incorporated into a utility room or cloakroom.
Useful diagrams provided by Which? may help you to visualise the inner workings of your ground source heat pump:
The pump itself requires a small amount of electricity to run, which can be sourced from a renewable electricity provider to create an entirely green solution. The higher the temperature the pump runs at, the more electricity it requires, so GSHPs are often a good partner for underfloor heating systems which supply a lower temperature over a wider area, rather than a traditional heating system using radiators.
Using something called weather compensation, a GSHP becomes an even smarter solution. When initially installed, you can program your expectations into the heat pump so it knows the temperatures you want your property to reach. Often, these settings don’t need to be touched again. The pump will adapt to the weather and temperatures around it. During winter, it’ll know the outside temperatures are lower, so it will work harder to keep your home at a comfortable temperature.
When spring and summer arrive, it senses a rise in the temperature, so reduces the load put on the system. This means that it is automatically using the lowest amount of energy and electricity to maintain a constant warm environment in your home – reducing wasted energy and thus saving you money.
The benefits of a ground source heat pump are wide-ranging and will not only benefit you, but also the environment. Providing you with a renewable source of energy, a GSHP will also help reduce your utility bills. Here’s some more details on the benefits a GSHP:
Decrease your carbon footprint: A GSHP has the lowest carbon dioxide emissions of any heating system when compared to mains gas, LPG, oil or coal boilers, or a direct electrical supply. A GSHP emits approximately 120kg of CO2 to produce 1000kWh of heat (compared to 450kg for a direct electrical system).
Save on your bills: In the UK, the money we spend on our heating and hot water accounts for the vast majority of costs for regular utility bills. A well-designed and correctly-installed GSHP system could save you over 50% on your heating and hot water bills.
Provide a safe home: A GSHP doesn’t burn fossil fuels, so you are safe in the knowledge that there is no chance of carbon monoxide poisoning for you and your family.
Be energy efficient: A ground source heat pump can run at up to 400% efficiency, meaning it produces four times more energy than it consumes. Much more efficient than even the best new gas boilers, which run at around 90%.
Long lifespan: A GSHP has an average lifespan of 20 years when maintained and serviced properly, compared to a traditional boiler which usually needs replacing after 8-10 years.
User-friendly: Using weather compensation, a GSHP can adapt and regulate itself to meet your needs – meaning you don’t have to bother with changing settings or fussing with thermostats. If you want, it can be controlled by a smartphone device for ultimate flexibility.
Renewable Heat Incentive. The Renewable Heat Incentive (RHI) rewards people for using renewable energy, so you can expect repayments over the course of several years to compensate for initial costs.
Our article, The Benefits of a Heat Pump, goes into more detail on these wins, and more great reasons to choose a GSHP for your home’s heating and hot water needs.
The world of renewable energy sources and heat pumps can be confusing! In your research, you may have come across these other terms and wondered if they all mean the same thing. Here, we’ll bust some myths and go through what they all mean, and which one is relevant to your property.
“GSHP”: This is a simple abbreviation that we, and many others, use for Ground Source Heat Pumps.
“Ground Heat Source Pump”: A subtle switch of word order, but important to note that many people search for “ground heat source pump” instead of ground source heat pump. They are one and the same.
“Geothermal Heat”: Geothermal heat is not feasible in the UK, and is rarely (if ever) used on a domestic basis. “Geothermal” refers to extracting heat from the earth’s core. You won’t be looking for this!
“Ground-Coupled Heat Pump”: A ground-coupled heat pump is the same a ground source heat pump, just a different terminology. As the name suggests, ground source heat pumps are “coupled with the ground”, so this term is also commonly used – although not here at Smart Renewable Heat. Ground-coupled heat pumps can refer to both vertical and horizontal ground source heat pumps.
“Underground Heat Pump”: An underground heat pump also refers to the same technology as a ground source heat pump. We tend not to use the term “underground heat pump” as it may lead to confusion, as actually the pump of the system is located above ground. It is only the pipe loops which are actually situated underground. A ground source heat pump better describes the fact that the heat is sourced from the ground, as opposed to the entire system being underground.
Before installation even begins, we will take you through a series of conversations, surveys and discussions to best understand the needs for your new GSHP system. We will also need to know about access on the site, where the pump is to be positioned, the space heating method in use i.e. underfloor heating or radiators, and what type of insulation your home utilises.
Once we have understood all of these variables, we will be able to begin planning for a smooth and hassle-free installation.
Whether a new build project or an addition to an existing home, the ground preparation work must come first. This means digging the trenches or drilling the borehole for the pipes to be laid.
The ground works for both vertical and horizontal systems will result in a fair amount of disruption, which is why on a new build site, it’s good to get it out of the way early on while other earthworks are underway to minimise lead times, disruption and unnecessary costs.
Once the trenches or borehole(s) are in place, it is time to install the pipe loops. Each project is bespoke, and the size and amount of trenches, boreholes and pipe loops will depend on the size of your system. One thing that remains the same is that if using a horizontal system, the pipes will be laid at a depth of one metre, and whether using trenches or a borehole, the pipes will lead into a prefabricated chamber which sits just under ground level. From this chamber, wider pipes will run directly into the plant room or wherever the heat pump itself will be located.
If on a new-build project, there is often some time between steps 2 and 3, while the rest of the build progresses. In most cases for new-build homes, the heat distribution method is underfloor heating, so once the site is ready for installation, we will return to site to complete this step. If we are adding a GSHP to an existing property, we can install a new heat distribution system if required. We can also connect the new heat pump to the existing heat distribution system if it is compatible.
This step on a new build project usually comes when the rest of the build is near enough complete. In an existing home, we can install the pump into the prepared space as soon as steps 1-3 are complete. The pump often sits alongside an additional hot water cylinder inside the plant room. The heat pump and cylinder will be coupled, and connected to the heat distribution and hot water systems already in place.
Almost time to get up and running! At this step, we purge the pipe loops and heating systems and flush any debris, to ensure smooth running once the pump is fully working. We will fill the pipe loops with the heat transfer fluid and set the flow rates to confirm everything is functioning as it should.
A successful handover is critical to the long term success of the ground source heat pump system. As a new system, we will educate you on how to use the system, easy maintenance tasks to ensure safe running and answer and queries or concerns you may have.
After that, it’s time to get started. The system will be running to our high standards and you will be confident in using it and enjoying the range of benefits it will bring you and your home.
If you like getting your hands dirty, unfortunately, this may be one job best left to the professionals. To be able to qualify for RHI payments and incentives, the pump system must be signed off by an MSC accredited installer – like us, at Smart Renewable Heat.
The one part you can play a role in are the ground works, and there is certainly nothing stopping you preparing the ground and digging trenches for a horizontal system, once we have given you clear and precise instructions. If you’re desperate for a DIY project, read our DIY ground source heat pump: what you should do article for more advice on what you should – and shouldn’t – be doing yourself.
Broadly speaking, ground source heat pumps are more expensive to install than conventional fossil fuel burning heating systems. However, there are a raft of financial support and incentive schemes to help with, and balance out, your initial outlay.
The Renewable Heat Incentive (RHI) rewards people for choosing a renewable energy source and provides quarterly repayments over 7 years from installation. This scheme is available to homeowners in England, Scotland, and Wales. And it is available to businesses in the form of the Non-domestic RHI.
In Scotland, the government can provide interest-free loans under The Home Energy Scotland Loan scheme – which can help cover the installation costs. Although there are currently no government funded grants to help ease the costs of installation, schemes such as the Assignment of Rights (private funded, government regulated) can also give helpful financial assistance.
We encourage everyone who is considering switching to a ground source heat pump to research these financial scheme options fully, to understand your initial costs and how quickly you can expect to see the return on investment for choosing a renewable energy source for your home.
Answering the question of how much installation of a GSHP costs is complex and will depend heavily on which type of GSHP system you are looking at – vertical or horizontal. So, we’ll break costs down into these two system types. Also, bear in mind that the size of your system will play a major part in the overall installation costs. Larger systems require larger trenches or more boreholes, a larger heat distribution system, and a larger hot water cylinder.
Here is a brief guide of costs for average sized vertical and horizontal ground source heat pump systems:
A typical 6-8kW horizontal system will cost around £12,500 to install. A 12kW system for a larger home may cost in the region of £15,500-£16,000. Digging the trenches, although a lot of work, is more economical than drilling a borehole for a vertical system. If you have the space for a horizontal system, it’s likely you’re situated in a rural area, in which case there may be locals who could help with the initial digging for less than employing specialist contractors. If you’re starting a new-build project, factoring in these groundworks costs into your overall build budget can help spread costs.
A 12kW vertical system will cost around £30,000 to install. Vertical systems are always more expensive than the equivalent sized horizontal system, due to the requirement of specialist heavy machinery in the way of the drilling rig to create the borehole. Each borehole may cost between £4000-£6000 to drill.
Despite the relatively high installation costs, both horizontal and vertical ground source heat pump systems will provide you with a good return on investment. You should expect to see the financial payback after approximately 3-4 years for a horizontal system, and 7 years for a vertical system.
Not only are the financial benefits real, but you should also consider the value added to your home for adopting a clean and low-carbon heating source. Energy efficient heating methods are increasingly favourable for many buyers when purchasing a home, especially off-grid homes, so can be a great USP for your future home sale. There will also be a very real effect on your EPC rating.
Trying to reduce the costs of installation is a risky decision – poor installation and maintenance can cost you thousands in inefficient running in the years to come. For more details on the costs for vertical and horizontal GSHP systems, read: What is the cost of installing a ground source heat pump in Britain?.
The running costs for your ground source heat pump will depend greatly on your specific situation: the size of the system, the type of property it is used for, the heat distribution method in place and how well the system is installed and maintained.
Broadly speaking, heat pumps are the most efficient heating source when compared against traditional methods. You can be assured that installing a new GSHP is a wise money-saving exercise in the long run, as well as boosting your home’s eco credentials.
As a guide, if you currently spend £1,000 a year using a gas boiler heating system, you could expect to spend around £750 annually when efficiently using a GSHP. The cost differential is far greater when comparing a GSHP to less efficient methods of heating, such as oil, LPG, or electric heating systems. You can use our free savings calculator to see just how much a new ground source heat pump system could save you on your heating and hot water bills.
Four main factors influence the running costs of your ground source heat pump, and should be considered before installation. Running costs will depend on the energy efficiency of your home and the heat pump system so you need to consider:
Essentially, the better your ground source heat pump is planned, installed and maintained, the less it will cost to run.
In the UK, we regularly install ground source heat pumps from 4kW up to 12kW, and this covers most residential home sizes. As a general rule of thumb, new-build homes which have 100 square metres of floor space – around average for British homes – we would usually install a 4-6kW ground source heat pump system. Passivhaus properties might require a slightly smaller system. Full renovations for existing properties are often 6 – 8kW and retrofit in old (solid-walled) properties might be 10-12kW.
Calculating the exact size of system you need for a new build home is fairly straightforward – and worked out early on in the planning phase. The home needs to meet certain insulation and heat loss criteria to comply with building regulations. We need this information to calculate your ground source heat pump system size requirement.
Working out the heat loss and therefore determining the GSHP system size required for older properties can be more difficult. That’s why for every installation, we complete a thorough on-site survey. We need to understand a range of factors: the number and types of rooms, the heat distribution method and the desired room temperatures. Then we can make the call on what size heat pump you need for your home.
Again, this will depend on the size of your home and the expected pressures put on the system. A horizontal system of shallow trenches require a much larger surface area under which to run the ground loops than a vertical system. This means that it is often an unlikely choice for homes in urban areas – where there can be a lack of outdoor space. A vertical borehole system requires less land surface area, but the need for a drilling rig can be prohibitive if access to the site is poor.
When you know what size pump system you need, you can determine whether you have space for a horizontal system – or if you may need to explore the idea of a vertical system.
If you need an 8kW system, you can estimate that you would need 700 square metres of land under which to lay the required length of ground loops for a horizontal system. For an 8kW vertical system, it’s likely you’d need 2 boreholes. These would measure approximately 25cm in diameter, and would need to be spaced 5-6m apart. Less space needed, but there must also be appropriate room for the drilling rig.
For more details on your spacial requirements, continue reading on this topic on our how much space is needed for a ground source heat pump? page.
Installing a ground source heat pump for your home is usually considered as a permitted development, meaning there is no need for planning permission in the UK. However, if you live in a conservation area or your home is a listed building, you should always contact your local authority to double check before committing to any definite plans.
Air source heat pumps are often subject to more planning restrictions, so is something to consider if you are trying to choose between the two heat pump types.
As with most factors to consider for your ground source heat pump, choosing the best brand for your home will depend on your exact requirements. Our Systems and Design manager, Jeremy French, has compiled a thorough review of 4 of the leading GSHP brands to help you see the wood for the trees in this crowded marketplace. As an overview, these brands should be where you start your search:
Nibe: With decades of Nordic experience behind them, this Swedish company’s ground source heat pumps are made with high quality components and boast of being the quietest GSHPs on the market.
Vaillant. One of the biggest heating product manufacturers in the world, Vaillant heat pumps are made in Germany – so as you would expect, a good, solid product.
Viessmann: A popular range of GSHPs, thanks to their compact sizes and relatively high running temperatures make Viessmann a good choice. They offer a range of German made systems to suit every scale project.
Thermia: Another Swedish company with a long history, Thermia produced the first recognised heat pump in 1973 and are at the cutting edge of heat pump design.
Worcester-Bosch: The range of Greenstore GSHPs are popular on the UK market thanks to Worcester’s long-standing reputation in Britain for quality home heating systems. Now owned by Bosch, the heat pumps are designed to fit systems of most sizes and most are solar compatible.
Mitsubishi: A recognisable brand name, Mitsubishi heat pumps are amongst the UK’s most used systems thanks to a good price point and high quality product.
Kensa: With a 20 year history, Kensa are relatively new on the scene, but boast of having the widest range of heat pumps and accessories on the UK market and all their products are made in Britain.
If you’re confused by the various options available on the market, don’t hesitate to contact us to talk about your requirements. We’re not bound by certain manufacturers, so all the products we recommend and install must meet the highest performance ratings, from accredited manufacturers. We can help you find the right ground source heat pump for your home.
This is a common question we get asked – and the short answer is no!
From one metre away, the noise an average GSHP produces is 42 decibels – which is similar to that of a standard domestic refrigerator. As there is no fan unit and the pump generally works on a constant low level, there are no parts or processes to produce a lot of noise. Through careful planning of the pump’s location within your home, the noise disruption can be even further reduced and regular maintenance and servicing will ensure the pump is running smoothly, and quietly, year on year.
Due to the lower running temperatures of a ground source heat pump, they do work more efficiently with underfloor heating than with traditional radiators. This is because underfloor heating systems cover a much larger area than a standard wall-hung radiator, so they have a far greater heat exchange surface. This means the difference between the running temperature of the system and resulting room temperature is less – so the system can run at a lower temperature (which is more efficient and has lower running costs), but still keep the rooms at a constant warmth.
You can get the same results by installing specially designed and “oversized” radiators. Factors to consider with a new radiator system include the impact on the functional space and layout of a room. You can’t block the radiators with large furniture, and must ensure there is sufficient wall space.
When embarking on a new build project or extensive renovation, including underfloor heating into the ground floor plans is simple and a common choice, regardless of traditional vs. renewable heat source. Installing underfloor heating onto a first or second floor of a property can be difficult and expensive and is not always necessary. “Oversized” radiators can provide common upstairs rooms, like bedrooms, with sufficient heating. Thus, many people choose underfloor heating for the ground floor, and a specially designed radiator system for any upstairs rooms as part of a new build design.
When fitting a ground source heat pump system into an existing or older property, the options for heat distribution system can be limited, but is something we have vast experience with. We can discuss how to make a renewable energy source work for your home, so if you’re not sure where to start, contact our team who will be able to give you clear and professional advice.
If you’re not sure that a ground source heat pump is the right choice for your home, rest assured, there are other renewable and energy efficient heating and hot water systems on offer. You may want to do further research on the following alternative renewable energy technologies:
As the name suggests, this is very similar to a GSHP. The difference being the heat energy is sourced from air around the unit, as opposed to the ground. Air source heat pumps require less outdoor space than a GSHP, as there’s no need for ground loops. Relatively low running costs also mean ASHPs are a good investment. They also qualify for the RHI – but with lower tariffs – and have a slightly shorter life expectancy than a GSHP, of around 15-20 years. Ground source heat pumps are almost always the most efficient choice, but read more pros and cons for the two heat pump options in this blog post.
Also known as a “dual fuel system” a hybrid heat pump is a system that combines a renewable energy source – an ASHP or GSHP – with a traditional heating system – gas, LPG or oil. A hybrid heat pump system monitors the most efficient running option constantly, so this system can maintain a consistent temperature for your home and hot water all year round, usually relying mostly on the traditional boiler in the Winter when the air and ground temperatures outside are lower. While we would always recommend adopting a totally renewable energy source for your home, in the efforts to reduce the use of fossil fuels, there are some occasions where this technology may be the most suitable option.
Solar panels are a common sight across the UK, and are a great source of renewable energy, harnessing the sun and converting it into usable energy for our homes. Due to our temperate climate, solar thermal panels are often unable to heat a whole home and hot water system, so must rely on another supportive heat source for the winter months in particular.
A biomass boiler works in a similar way to a traditional gas boiler, but requires logs or wood pellets to burn. Thanks to the natural life-cycle of trees, wood products are classed as carbon-neutral when burnt. Across the UK, many people have access to a local supply of wood fuel, therefore prices are often more stable than relying on the global gas market. But a biomass boiler can be tricky due to its size. They’re large units, requiring a plant room of substantial scale. This needs to be factored into a new build project, and means a biomass boiler isn’t automatically a good fit for existing properties.
With the UK government’s Net Zero 2050 target, we’re looking forward to what the future holds for renewable energy, and the impact these solutions can have on our country’s CO2 emissions.
We hope this guide has given you the information you need to start planning your home’s energy efficient and low-carbon future. At Smart Renewable Heat, we are passionate about the role of ground source heat pumps in the UK’s decarbonisation of heat. We can help you reach your own carbon reduction goals, so take the first step of your journey by contacting our experienced team today.
Please contact us using the form below, or call us on 0800 865 4328.