Frequently asked questions
Shenstone heat network feasibility study is based on an ambient open-loop system. An open-loop system typically requires a minimum of two boreholes: one for pumping the natural groundwater directly from the aquifer (abstraction) and another one for returning the groundwater to the aquifer after thermal exchange (re-injection). However the final number of boreholes will depend on the size of the network and heat demand.
After the heat is extracted, the cooled water is returned to the aquifer via a separate borehole much further upstream. This avoids thermal interference, keeping the temperature in the aquifer at a more consistent level and supports sustainable energy extraction.
This type of system works well with the qualities of the aquifer - a reliable supply of groundwater, relatively stable subsurface temperatures, good flow rates, and the fact that water is an excellent carrier of thermal heat, which means a higher amount of thermal energy can be extracted from the subsurface than by closed-loop systems. The efficiency of open-loop systems are often preferred for the supply of substantial heating or cooling requirements, such as for a heat network.
Closed-loop systems use different configurations of buried pipes, typically installed in the shallow ground, which circulate a heat transfer solution in a sealed loop. The loop is filled once and the same solution (a mixture of water and a small amount of antifreeze) is used continuously.
The pump draws water through a screened well, which filters out sand and larger particles before the water enters the system. Additional inline filters or sediment traps may be used to protect the heat pump equipment.
In an open loop system, water is pumped directly from the aquifer and passes through a plate heat exchanger before being circulated and returned to the aquifer.
In a closed loop system, a sealed network of pipes circulates a brine solution that absorbs heat from the ground. The fluid never comes into contact with groundwater or the surrounding soil.
It uses water mixed with a non-toxic glycol (a type of antifreeze) to prevent freezing. This mixture is often called brine.
No. With good design and sufficient boreholes, the system is sustainable and self-renewing, drawing on the steady temperature of the ground without depleting it.
In a closed loop system, a plastic pipe (usually high-density polyethylene) is installed in the borehole, and a thermal grout is injected around it to ensure good heat transfer and seal the borehole.
In an open loop system, a well casing is used to line the borehole and protect the water source.
The two systems use different lining approaches because they operate differently—closed loop circulates a fluid within sealed pipes, while open loop draws groundwater directly.
Depending on your heat demand, the heat pump will likely be the same size as a domestic fridge freezer. The hot water tank is built into many ground source heat pumps, meaning you don’t need to find more space for the tank. Larger heat pumps, 15kW plus, may require a separate tank.
Will I need to adapt my heating system?
To connect to the heat network, each participating property will need to replace its gas boiler with a ground source heat pump. The heat pump will be powered by your normal electricity supply and will upgrade the heat to a usable temperature when needed.
If your radiators are effective and of sufficient size to meet your current heating needs, it’s likely you will not need to make any upgrades. However, if your radiators are not meeting your current heating needs, you may need to install larger radiators.
Yes you do need a hot water tank.
Upgrading your windows and insulation is always a good idea, even when using a gas boiler. This reduces your energy bill. Heat pumps can still be used in older buildings with poor insulation or single glazing, but they may be bigger units as a result, to overcome the higher building heat loss.
Solar panels are not needed to run a heat pump but can reduce the running cost, especially if paired with a battery system.
Ground source heat pumps tend to be very quiet, with a similar noise level to a fridge freezer.
If you have enough room in your house, you can keep your boiler as a back up. If you apply for the Boiler Upgrade Scheme, however, you will need to remove your boiler.
Yes, absolutely! Underfloor heating works best with low temperature hot water so is perfectly suited for a heat pump.
Yes, many heat pumps can provide both heating and cooling. However, your heating system’s emitters may need to be upgraded to take advantage of this.
Standard radiators and underfloor heating aren’t effective for cooling. Instead, you would need cooling-compatible emitters like convector radiators or fan coil units to deliver comfort in warmer months.
Smaller domestic systems, up to around 40kW, typically do not need a 3 phase electrical supply.
Ground source heat pumps do not rely on air temperature to heat the water, so are less affected by cold weather. The ambient heat network serving each heat pump tends to stay at very stable temperatures all year round, so the heat pump will provide efficient heating in all weathers.
Disruption will largely focus around your boiler. This will need to be removed and replaced with a heat pump. There may be some requirement to move and adjust pipework in that area. If any radiator upgrades are required, this will cause more disruption as this could affect some or all the rooms in your house, just as any other plumbing project would.
Air source heat pumps are installed outside the home, typically near a wall or in the garden. However, they require indoor space for a hot water cylinder and associated pumps, valves and controllers. These components can usually be housed in a garage, utility room or airing cupboard, depending on the size of the system and the home.
Ground source heat pumps are typically installed inside the home and are often similar in size to a fridge freezer. Some models include an integrated hot water cylinder, while others require a separate cylinder, which also needs indoor space.
Good planning during installation can ensure the system fits comfortably within the home’s existing layout.
An ambient loop heat network requires significantly less construction work compared to traditional high-temperature district heating networks, mainly because the lower operating temperatures allow for smaller pipes, shallower trenches, and often less insulation. However, the amount of disruption will depend on the size and layout of the network, the terrain and existing infrastructure.
Construction required:
· Excavation for trenching
· Pipe installation
· Pumping station to circulate the water through the loop
· Heat pump installation in each property
· Building connections – connecting network pipes to individual buildings
By moving from natural gas for heating and hot water, to using grid electricity, the typical carbon savings will be 75%.
This is based on current government figures on carbon emissions for natural gas and grid electricity, a boiler efficiency of 85% and a heat pump Coefficient of Performance (COP) of 3.5. As the national grid continues to decarbonise, or if you are generating your own power with solar panels, the carbon saving will be greater than 75%.
Yes, we recommend installing a battery alongside solar panels. The rates paid for exported energy have dropped significantly, yet the cost of electricity you buy from the grid remains high. By using a battery to store your excess solar power, you can use it later—reducing your reliance on grid electricity and increasing your savings.
We recommend starting with one of the trade associations - Heat Pump Association, Ground Source Heat Pump Association, Solar Energy UK. If installers have taken the time to register, they should have a good reputation. Also ask friends, neighbours and relatives; word of mouth recommendations are always a good start
No. The system is non-consumptive — all water extracted is returned to the ground after use. There is no net water loss.
If we use the Lynn Lane pumping station, the water used in the network will be heated by the water that used to be used for drinking water before it became unusable. However, drinking water can and is used in similar networks around the country.
Switching to low-carbon heating—such as heat pumps and solar panels—has several positive environmental impacts:
Lower carbon footprint: replacing fossil fuel heating with renewable systems significantly reduces greenhouse gas emissions.
It can also improve the home environment. With the right emitters (such as well-sized radiators or underfloor heating), homes can become warmer, more evenly heated and more comfortable year-round.
Better energy security: using locally generated energy (like solar) and electrified heating reduces reliance on imported fuels.
Improved air quality: electric heating systems produce no local air pollution, unlike oil or gas boilers.
Yes, heat pumps can be successfully used in historic or traditional buildings, including many National Trust properties. For example:
Plas Newydd in Wales uses an innovative water source heat pump drawing energy from the Menai Strait.
The National Trust has also installed heat pumps in restored barns converted into holiday cottages.
The North Aston Estate in Oxfordshire installed a closed-loop ground source heat pump system to heat 26 estate cottages.
These and many other cases show that with the right design, heat pumps can work effectively in older, heritage properties.
Domestic wind turbines don’t tend to generate enough power to make a good payback.
Commercial turbines are an option but would require a specialist survey. Planning permission can take time for turbines. However, turbines can work well with solar, covering for when it is not sunny.
HI Group provides comprehensive renewable energy solutions for large scale sites, communities and businesses.
Their expert support ranges from strategy to installation and ongoing optimisation with proprietary monitoring software to achieve measurable carbon reduction and costs savings for customers.
Bringing together cutting-edge technology, smart financial strategies and an unwavering commitment to the environment, they ensure every tailored solution contributes to real, impactful change for both your organisation and the planet.
For further information, see: www.higroupltd.co.uk