Ground Source Heat Pumps: A Complete Guide
Is a Ground Source Heat Pump the Right Investment?
Ground source heat pumps are an effective and environmentally-friendly investment that can help you save up to 50% on heating bills when compared to conventional heating systems. Initial investments are high, but the ground source heat pump prices vary depending on the project and the household specifications.
Few of the many advantages include:
- The savings on your electricity bills. Save from £790 to £1425/year on your heating bill when replacing an electric system
- The Long Lifespan of the product. Inside components last approximately 25 years, while the estimation for the ground loop system exceeds the 50 years (reaching up to 80 years)
- Equal distribution of heat.
- Constant performance throughout the year.
Since the earth absorbs energy released from the sun, underground temperatures remain stable all year round. In the UK, the temperature of the earth (a few metres below our feet is) constant around 8-11°C. The purpose of the product is to absorb heat from one place and transport and release it to another location, in this case, your home.
Ground source heat pumps play an important role in the UK's goal of reaching Net Zero by 2050. With the new heat and buildings strategy coming up, it is expected to further increase the installations of various heat pumps as a low carbon heating solution.
If you are ready to install a ground source heating system, fill out the form on this page, and our customer service team will provide you with up to four different quotes to help you find the best ground source heat pump. Our service is free and without any further obligations.
Learn More in Our Guide
What Is a Ground Source Heat Pump?
A ground source heat pump extracts heat from the ground to heat up your home. It can be used for both space heating (such as radiators or underfloor heating), as well as domestic water heating.
Ground source heat pump systems have various components:
- An underground heat exchanger
- The distribution system
A mixture of water and antifreeze is pumped into the ground via the heat pump, and the antifreeze mixture is continuously warmed up by the constant temperature of the ground.
The liquid is fed into a heat exchanger and energy absorbed from the ground is transferred to a refrigerant, which boils at a low temperature until it turns into a gas.
The gas is fed into a compressor and the compressing process makes the temperature of the gas rise.
This is then fed to a condenser, where it is distributed to the wet central heating system of the house, such as radiators, showers, faucets, and underfloor heating.
The video below explains how a ground source heat pump works:
Types of Ground Source Heat Pumps
The first step in assessing the type of ground source heat pumps is to research the ways of minimising the hot water demand and space heating.
It requires accurate energy efficiency measurements, which can be done by obtaining an Energy Performance Certificate (EPC). It helps to find the heat pumps of the right sizing that will decrease the energy consumption, heat loss, and hot water needs.
Ground source heat pumps are typically more suited to new-builds than retrofits.
There are two different types of loop systems for ground source heat pumps, the open loop system and the closed loop system.
The open loop system extracts groundwater which passes through a heat pump where heat is extracted. The closed loop system draws the heat from the ground itself and uses a continuous loop of piping connected to the indoor heat pump.
There are several types of closed loop systems:
Horizontal Ground Source Heat Pump
The ground source heating system is laid in horizontal trenches that are approximately 1-2 metres deep. It is more common in rural areas where there is more land available. To install the horizontal system, the area required depends on the heating and cooling loads of your home, the depth at which your loop is going to be buried, your soil and its moisture, the climate, and the efficiency of the heat pump. The average 150 m2 home needs an area of between 300 and 700 m2.
Vertical Ground Source Heat Pump
The ground source heat pump borehole cost can vary. Vertical boreholes are a more expensive alternative when there is not enough area to lay the pipes horizontally. It is more often the appropriate choice for suburban homes where space is restricted. A hole is dug at least 6m into the ground for insulation and the total piping will be 50-150 m deep depending on the composition of the ground and the heat requirement of your home.
Closed Loop System for Pond/Lake
Although less common than horizontal or vertical systems, a closed pond loop is also an option. It is uncommon because it requires proximity to a body of water, so an open loop system is usually preferable. It may be advantageous when poor water quality prevents the use of an open loop.
Other types of Closed Loop Systems
Direct expansion (DX)It relies on a cyclical process when the refrigerant changes its position back and forth between a gas and a liquid. When the refrigerator absorbs the heat, the compressors start pulling the vapour from suction lines and the process is launched.
Indirect expansionIt is commonly used in freezer applications with carbon dioxide when changing secondary working media. In other words, during antifreeze solution/water circulation the energy is relocated from or to the refrigerant circuit through ground heat exchange pipework.
How Efficient the Ground Source Heat Pumps Are?
For every kW of electricity consumed by the heat pump, around 3-4 kW’s of heat is generated in return. This means a GSHP has, on average, a Coefficient of Performance (COP) of 3.5 to 4.5.
GSHP systems save energy by using the constant temperature of the ground to increase the seasonal efficiency of home heating. The source of heat used for ground source heat pumps is the sun, as it heats up the ground water resulting in the stable temperature of the Earth’s floor.
The type of soil also affects the efficiency of ground source heat pumps. The thermal properties of soil in the UK vary a lot by region, therefore, to get an accurate estimation of efficiency, it's important to get your specific property assessed by a professional.
Are Heat Pumps Efficient in Cold Weather?
The heat pump's external pipelines are inserted in the soil which keeps its temperature below 1 meter relatively stable all year round. For this reason, cold weather is not likely to affect your heat pump's efficiency significantly, and even less so if you have a vertical GSHP.
What Do the COP and SCOP Tell Us about Efficiency?
Ground pump systems reach rather high-performance coefficients, with an average between 3 and 4. The Coefficient of Performance is found by dividing the useful heat output by the electrical energy input.
A ground source heat pump that transfers 4 kilowatts of heat from the ground for 1 kilowatt of electricity has a COP of 4. We recommend you check out the seasonal coefficient of performance (SCOP), as it is a more accurate representation of the efficiency during different times of the year, compared to the COP.
While the COP is the performance delivered at a specific moment, the SCOP will provide an average for the whole year, giving a more trustworthy figure.
Installation of Ground Source Heat Pumps (3 Basic Questions)
House size and building requirements will determine whether a vertical or horizontal loop system is needed. The first step is the excavation of the loop fields.
To install a vertical ground source heat pump, the loop is placed in the drilled well that is dug deep 50-150m the ground. The heat exchanger is then installed in order to capture the heat from the ground.
For horizontal installation, a large area of land is dug up so that the loops can be placed on the land without having to dig deep into the earth.
How Much Space Is Required for a Ground Source Heat Pump?
Horizontal GSHPs require large space, as for an average family household, around 600 meters of loops need to be laid in the ground, which would total to around 700 m2 to dig up. To save space, some decide to lay the pipes in many loops (figuratively called 'slinkies') which, however, reduces efficiency somewhat.
Vertical systems do not require as much surface area, as boreholes are dug vertically into the ground. The depth of the borehole depends on the system size; an 8kW ground source heat pump system would require approximately three boreholes.
How Long Does It Take to Install a Ground Source Heat Pump?
Once planning, preparation, and getting the necessary permissions are done, the groundwork and laying the piping system usually takes 1 or 2 days. Depending on the geological conditions, the installation might require 3 days in case of a borehole GSHP. Finally, the heat pump device itself needs to be installed and connected to your heat distribution infrastructure.
Do You Need Planning Permission for a Ground Source Heat Pump?
It is important to note that special planning permissions are required in Wales and Northern Ireland, and in England and Scotland permissions depend on your location and the size of your property.
Prices of Ground Source Heat Pumps
A ground source heat pump can cost between £16,000 and £35,000 to install in your home. The running costs depend on the size of your home and how well insulated it is. The set-up costs of ground source heat pumps are higher than other systems, but the difference is usually compensated by energy savings, and there are heat pump grants that help with the costs.
When you are trying to figure out how much a ground source heat pump costs, you need to bear in mind that this also depends on whether any new radiators or a fully new underfloor heating system is required, therefore the price estimations below don’t include any wet system upgrade.
Groundwork Costs of Vertical vs. Horizontal Systems
There is a significant difference in groundwork costs between horizontal and vertical systems. Although the horizontal installation is cheaper, it requires a minimum of ½ an acre of land.
|Number of Rooms||Heat Pump and Installation Cost||Horizontal Groundwork Cost||Vertical Groundwork Cost|
The costs depend on each individual case and numbers do not represent actual offers. They are merely for general reference.
How Much Money Can You Save with Ground Source Heat Pump?
The following is a table based on figures from the Energy Saving Trust, outlining the carbon dioxide and energy bill savings when using a ground source heat pump in England, Scotland and Wales. The existing systems listed are all non-condensing systems, which are likely the systems users are looking to replace.
|Current System||Savings on Energy Bill
|Carbon Dioxide Savings
What Brands Sell GSHPs?
Ground source heat pumps differ in efficiency, price, and brands. Certain brands may have similar efficiencies and prices, yet some brands are available at higher costs than others.
There are many brands of ground source heat pumps available in the UK market, some of the most known brands include Baxi, Calorex, Bosch and Mitsubishi. Due to the large variety of brands available, it is important to compare supplier quotes to help make your decision easier while choosing the most competitive price.
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Advantages and Disadvantages of GSHP
Contrary to popular belief, you don’t need several acres of land to install a heat pump. Even a modest garden can be used to benefit from the Earth’s heat. There are many advantages of heat pumps that you can enjoy when you install one. And, as with any type of installation, there are also disadvantages to keep in mind:
- One of the most energy-efficient water heating systems
- Low maintenance and low running costs
- Less noisy than gas boilers and air source heat pumps
- Low environmental impact
- Longer lifespan of components compared to air source heat pumps
- High up-front costs
- Dependent on the type of bedrock
- Space requirement for horizontal systems
- Not ideal for retrofits, as they are better suited for new-builds
- Is questionable how environmentally-friendly some liquids are when the heat is transferred
Underfloor Heating System vs. Radiators
Ground source heat pumps and radiant floor heating work very well together—this is actually the way to get the maximum out of your heat pump.
An underfloor heating system performs better than radiators because the heat is transferred equally across the whole surface, whereas radiators need to spread the heat from one corner to the entire room.
However, due to the higher cost of underfloor heating, radiators are also a good choice that results in high performance. The SCOP is higher for underfloor heating compared to radiators because heat distribution is well designed with underfloor heating and therefore the floor system will likely have a lower output temperature than a radiator, meaning a higher coefficient of performance.
Does the Government Provide Grants for GSHP?
With incentives available from the UK government, saving money on heat pumps has never been easier. Currently, the Renewable Heating Incentive pays 21.17 p/kWh of energy generated by ground source heat pumps.
Payments are made on a quarterly basis over seven years. A number of funds you receive will depend on a number of factors - including the technology you install, the latest tariffs available for each heating solution and, in some cases, metering.
The Non-Domestic Renewable Heat Incentive (RHI) aims to compensate for the costs of ground source heat pumps installations in commercial applications. The business owners and social housing providers benefit from a quick payback and long-term rate of return. In addition, the UK Government financial support gives an opportunity for retrofit installations and new houses to get modernised.
The RHI is expected to close in 2022, with a new grant expected to take over. This new grant is called the Clean Homes Grant, and unlike the RHI, will be an installation grant. This grant scheme is anticipated to come into effect in April 2022.
Another type of grants is the Energy Company Obligation (ECO). This grant imposes legal obligations on energy suppliers to carry on energy efficiency measures. The main focus is on three different areas: Home Heating Cost Reduction Obligation, Community Obligation and Carbon Emissions Reduction Obligation.
Finally, you could get a reduction in VAT on your ground source heat pump. If you are over 60 years old or receive income or disability benefits, you could receive a 5% tax reduction. Depending on the costs, you can either get a discount on the whole product or only on the installation.
If you are interested in buying the best ground source heat pump, we are here to help you. Simply fill in the contact form with your details and preferences and we will get back to you with customised, free, and no-obligation quotes!
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