A ground source heat pump is a great system to implement in order to warm your home by utilising the natural heat of the earth. In simple words, the system transfers the heat of the ground into your home rather than burning any gas or oil. It thus warms your home and keeps it cosy by using much less energy.
The system works as part of a geothermal heating system, which uses a network of pipes buried underground, called ground loop heat pumps. The ground is just as warm every month of the year, so even in the winter, the pump can extract heat from it and supply it to warm your home and water.
It’s a green option that can cut your energy bills as well as your carbon footprint. But just how does it work? Let’s discover.
What is a Ground Source Heat Pump?
A ground source heat pump (GSHP) is an eco-friendly heating system harnessing natural Earth heat to warm your home and water. Rather than your house being heated using oil or gas, it picks up heat from the ground and transfers it to your central heating system.
The pump is installed inside your house and is connected to underground pipes called ground collectors. These are set in horizontal trenches (1.5–2 m beneath the ground) and vertical boreholes (100 m deep).
Because the ground stays at the same 10–12 ° C all year long, it’s feasible that a GSHP could deliver consistent, effective heat. And so lower fuel and also carbon emissions.
How Does a Ground Source Heat Pump Work?
A ground source draws heat from the earth and distributes it to your building. This happens in a step-by-step process:
1. Absorb the Warmth of the Earth
The underground pipe, also called a ground loop, is installed in trenches (horizontal) or boreholes (vertical). The pipes contain a special mixture of water and contain antifreeze called thermal transfer fluid (TTF) or brine.
As the water travels over the soil, the natural soil temperature, 10–12 ° C throughout the year, is absorbed by it.
2. Heat Transfer to the Heat Pump
The liquid is then pumped back to your home heat pump system. The heat pump transfers the heat from the heat exchanger liquid in the heat pump to a refrigerant.
3. Increased Temperature
The refrigerant is compressed, which raises its pressure. The temperature of the gas is increased by compressing it. The process thus carries low-grade heat from the ground to a very high temperature.
4. Distributing Heat in the Home
The warm refrigerant is passed through another heat exchanger. It exchanges heat with the water. This hot water is then:
- Sent to the radiators or underfloor systems for efficient space heating.
- Used to fill a hot water cylinder to supply taps, showering, and bathing.
5. Cooling and Restarting the Cycle
After transferring heat, the refrigerant is cooled down and reverts back to its original state. The process repeats itself repeatedly, providing the heat continuously to your house.
Closed-Loop vs Open-Loop Heat Pump
Closed-loop heat pumps transfer the same liquid in a closed loop by means of ground pipes.
The open-loop heat pump uses water from a natural source (lake, well, etc.) extracts heat from it, and deposits it back into nature.
Most houses in the UK utilise closed-loop systems. This is because they are easy to use, and they also use low maintenance. The entire process is done through electricity, but because the heat is drawn for free from the ground, a GSHP uses a lot less energy than a heating system.
How Warm Is Ground Source Heating?
A ground source heat pump can heat your home just as well as a gas boiler. Many homeowners also find it more comfortable because the heat is stable, without a sudden change in temperature.
A heat pump can increase the temperature from the ground if necessary may exceed 60 ° C. But the higher the temperature, the more electricity will be used. Ideally, the system should move efficiently at low temperatures, usually about 50 ° C.
The right temperature depends on:
- The level of insulation – A good insulated house requires less heating.
- Outdoor temperature – High heat production may be required in cold weather.
- Radiator size – A large radiator or underfloor heating works best with low temperatures.
If your home loses too much heat, you need to add insulation even when you have a heating system. Otherwise, you’re wasting energy and money.
Ground Source Heat Pump Efficiency
They are extremely energy-efficient as ground source heat pumps utilise natural heat from the ground. The heat is a result of solar energy that has been absorbed by the Earth and is very constant over a time span of one year.
But efficiency can differ on this point:
- Soil Type – Various soils carry varying heat.
- System Design – The borehole vertical systems function better in winter.
How Efficient Are Ground Source Heat Pumps?
Ground source heat pumps’ efficiency is typically 300–400%. They can generate 3–4 times the heat that they use. It is quantified by:
- Coefficient of Performance (COP): Ratio of output heat to input electricity. A COP of 4 indicates that 4 kW of heat is generated for every 1 kW of power input.
- Seasonal COP (SCOP): This provides a yearly average efficiency, which provides more realistic figures of performance.
The most important thing to do to get the best efficiency is to have a professional evaluation to make sure that the system will be suitable for your home.
Pros and Cons of Ground Source Heat Pumps
Here are the pros and cons of ground-source heat pumps:
| Pros of Ground Source Heat Pumps | Cons of Ground Source Heat Pumps |
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Ground Source Heat Pump Installation Cost
Installing a ground source heat pump (GSHP) is an important investment. The total cost depends on the type of installation, property size, and heating requirements.
On average, a GSHP installation costs between £ 20,000 and £ 30,000 for a home with a specific three-bedroom. If the system uses trenches, the cost is usually around £ 28,000. If a borehole is required, the price may be even higher.
Many factors affect installation costs:
- Ground status: Borehole spends more than trenches, but the trenches require more space.
- Property type: The new build is easier and cheaper to install an old house than retroping.
- Heat pump size and brand: Larger houses require large systems, which cost high.
- Radiators and underfloor heating: Some houses may require upgrades to work efficiently with heat pumps.
GSHP Running Cost
Ground source heat pumps are cheaper to run compared to traditional heating systems. They work efficiently using heat from the ground instead of generating it from scratches.
- Low energy bill – They use less power than traditional heaters.
- Minimum maintenance – No annual servicing like gas boilers.
- Constant performance – Efficiency remains high even in winter.
The exact moving cost depends on electricity prices, home insulation, and heat pump efficiency. A well-installed GSHP can significantly reduce the heating cost over time.
How Much Money Can You Save with a Ground Source Heat Pump?
Here is how much you could save each year compared to other heating systems:
| Existing System | Annual Fuel Bill Savings (£) | Carbon Savings (kg CO₂/year) |
|---|---|---|
| Newer gas boiler (condensing) | £90 | 3,000kg |
| Older gas boiler (non-condensing) | £550 | 4,500kg |
| Electric storage heater | £1,200 – £2,000 | 4,500kg – 5,000kg |
| Older oil boiler | £600 | 7,000kg |
| LPG boiler | £500 – £1,100 | 5,000kg – 5,500kg |
| Coal | £1,300 | 12,000kg |
Government Grants for Ground Source Heat Pumps
Installing ground-source heat pumps can be expensive, but government grants can help reduce costs.
- Boiler Upgrade Scheme (BUS): The scheme provides £ 7,500 for the cost of installing heat pumps in England and Wales.
- The ECO4 Scheme: This is aimed at low-income houses and can cover up to 100% of the installation cost. Eligibility for the grants depends on income, benefits, and property types.
These grants make the heat pump more cheap and encourage homeowners to switch to cleaner heating.
Simple Tips for Ground Source Heat Pump Maintenance
Regular maintenance goes on your heat pump efficiently and expands its lifetime. What do you need to do here:
- Check the filter: Change them regularly or replace them to prevent interruptions.
- Monitor system pressure: Low pressure can reduce efficiency, so keep an eye on it.
- Flush the system when needed: Over time, mud and debris can affect and effect the performance.
- Inspect the ground loop: While underground pipes can last for decades, sometimes check that there are no leaks.
- Get professional servicing: To work on extreme efficiency, one heat pump must be served every 1-2 years.
The Bottom Line
Ground source heat pumps are low-maintenance, cost-effective, and energy-efficient for the long term. They save the heating bill by a minimum of £ 2,000 a year and minimise carbon emissions.
Although the cost of fitting is expensive, help can be obtained through government grants. The systems are effective all year round, furnishing constant heat as well as hot water.
A ground-source heat pump is something to be considered if you are looking for a long-term, lasting heating system.
FAQs
A heat pump takes heat from the ground and transfers it to your home through a refrigerant cycle. It is essentially a reversed refrigerator that delivers heat and hot water.
Yes! The ground source heat pump saves on bills, for a span of approximately 25 years, and can function well all year round. They are particularly useful for houses converting to electricity, oil, or LPG heating.
Yes! The earth stays at a constant temperature beneath the surface, so the system keeps functioning even during cold temperatures.
The majority of systems heat water to 60°C, with other models heating water to 70°C with extra functionality. The standard shower temperature is 40°C.
