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Geothermal Boreholes

Geothermal Boreholes, as commonly understood, refers to boreholes drilled to depths of 80m to 250m to harvest the absorbed solar heat stored in the outermost layer of the earth for use in Ground Source Heat Pumps (GSHP's). This is a misleading definition, because true geothermal heat harvesting would require the drilling of boreholes to much greater depths, to tap into the heat radiating from the molten core of our planet.

Synergy Boreholes and Systems Ltd. drills and equips boreholes and installs borehole arrays for GSHP's. We have done this for many years. We use only the best materials, e.g. individually factory tested and certificated PE100+, Crack Resistant Loops. We adhere to the latest industry standards.

In partnership with selected renewable energy companies we also offer the complete GSHP package. We do this with the most modern equipment. Our rotary hydraulic drills can drill to 250m. We use either mud flush, or air drilling techniques. With mud drilling we use automatic filtration / recycling units to keep mess and disruption on site to a minimum.

We are not providers of the cheapest borehole arrays. 

It has been reliably demonstrated by independant Thermal Response Testing, that closed loop geothermal boreholes drilled by Synergy consistently have a thermal efficiency equal or better than that predicted.

This is down to our drilling equipment and best practice techniques.

Excessive use of power during the drilling operation, often employed to speed up the drilling process and reduce the cost of borehole drilling, can and often does, reduce the heat harvesting capability of the boreholes by up to 50%.

Therefore, a cheaper drilling quote can be often end up very much more expensive in terms of the borehole metres needed to achieve the same result as correctly drilled boreholes, and/or may lead to the GSHP installation not producing the savings expected. (more...)

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Our corporate clients

Alternative Energy | Ambivent | Anders Heating Company | Ardenham Energy | Baker Associates | Barton-le-Clay Scout Hall | Bascomb & Drew | Baufritz | Better Planet | Blackmoor Knight | Blewbury Sports Complex | Calverton Manor | County Construction | Danaher & Rolls | David Kerwood Construction | Donnington Grove Country Club | E.M.E | Exedra Architects | Fairfax Homes | Farnrise | Feltham Construction | Fennes Estate | Frost’s Landscapes | Geothermique | Ground Source Consult | Guard Tillman Pollack | H2O Irrigation | Haileybury School | Ham House | Hampton School | Henley Town Football Club | Herring Homes | Isoenergy | J & S Seddon | Lad Construction | Laing O’Rourke | Leonard Properties | Lewis Wyatt | Mark Guard Architects | Morgan Shankly | Oakbridge Homes | Panshanger Golf Complex | Paynes H & P Plumbing Services | Projekt Plus | Quadrant Corporate | redblue(Germany) | RI Building Services | St. Stephens Church (Lympne) | St.Catharines Court | Summerleaze | Sutton Griffin Architects | Terra Firma Energy | Terra Mech | The American School in England (TASIS) | The Jockey Club | Timpson | TJ Thickett & Associates | Waltham Place | Welyn Hatfield Council | Wensley group | Wessex Group | Woods Commercial Facilities

What is Geothermal?

Ground Source Heat Pumps as installed in the UK generally do not utilise the heat radiated by the earths core but rather that which is absorbed and stored by the outermost layer of the earths surface from the radiated heat of our... Read more

Why go for Geothermal?

Of all the green/renewable heat sources geothermal is by far the most constant and reliable.

Its disadvantages are

  1. Its initial installation cost (this is now subsidised by government),... Read more

Ground Source Heat Pump Association (GSHPA)

The Ground Source Heat Pump Association (GSHPA) is the national body that represents the interests of the industry, that is, the industry made up of the heat pump manufacturers, system designers, installers and the associated technologies e.g... Read more

Why use Synergy?

Synergy has a long history of providing geothermal borehole installations to private clients

Synergy operates to the standards expected of an ISO 9001 accredited organisation. We use the best, therefore not necessarily the... Read more

The Best Advice

When designing a Ground Source Heating system it is essential to observe and accomodate the requirements of the structure and the functions/needs of the users/inhabitants of that structure. This requires accurate assessment of, heating/cooling... Read more

Synergy Borehole thermal efficiency

Value for money

Drilling method can significantly determine the thermal performance of the borehole.

It is well known that site geology, the groundwater, its presence and movement, determine borehole... Read more

New GSHP Industry Standards

The following standards and guidelines represent major initiatives to drive up quality standards in the Ground Source Heating Industry.

Consumer confidence in our industry is essential to its long term growth and... Read more

What To Expect From A Heat Pump Installer

Householders should check that the installer is a member of the two industry led and government approved schemes: the Microgeneration Certification Scheme (MCS) and Renewable Energy Consumer Code (RECC). The MCS scheme will cover any... Read more

Requirement Calculations

These must be conducted by an experienced professional and not a high pressure salesman. If not done correctly, the result can all too often be a heat pump sale with an underestimation of the borehole requirement, leading to a negation of the... Read more

How many, how deep?

The GSHP (ground source heat pump) specified by the installer or consultant will be defined by its power rating (kW) and COP (Coefficient Of Performance), these two parameters, together with the predicted borehole heat harvesting capability will... Read more

Geological Survey / TRT / Design

Geological surveys and/or TRT's are strongly recommended for larger GSHP installations

A geological survey will give a strong indication of the thermal characteristics at the site where the boreholes are to be drilled... Read more

Why is COP crucial to borehole dimensioning?

COP (Coefficient Of Performance) is the figure expressing the efficiency of the heat pump

It has many similar characteristics to the MPG (Miles Per Gallon) figure given for cars, in that

How much will it cost?

Leaving aside all the ecological and moral arguments for a moment. The most asked question is: How much do I have to spend to get a GSHP / Boreholes package? This question can elicit an uncharacteristic coyness in some GSHP salesmen, who will try... Read more

Financial Considerations

To install a Ground Source Heat Pump system with boreholes requires a significant financial commitment. The obvious questions are therefore
  1. How much will it... Read more

geoKOAX Technology

geoKOAX, is the proprietary name of a different and innovative collector type developed by the German geoKOAX GmbH.

This is a coaxial vertical collector installed in boreholes of a larger diameter than... Read more

Boreholes for Cooling

Ground source cooling can be used to cool buildings. This approach is less expensive than air conditioning which provides cooling by heat exchange with external air – often hot air. Ground source cooling is a mechanism of allowing the... Read more

Borehole (Array) Dimensioning

The importance of correct GSHP and associated borehole dimensioning cannot be overstated. It is not unheard of for salesmen to "underestimate" the dimensions of borehole requirements in order to make a quick heat... Read more


The geology of the site where a geothermal borehole array is to be located has a very significant effect upon the likely performance of the boreholes in terms of their efficiency in harvesting the heat from the... Read more

GSHP System Design and Installation

Should you be considering the installation of a GSHP system, it is certainly worth doing a little research about how they work and the benefits they bring. It is also worth looking around for a good renewable energy company to take charge of the... Read more


Synergy will provide the client with comprehensive documentation of the project.

This begins with the quote submitted in writing, this will clearly describe the following:-

  • The quote will list all the services that Synergy... Read more

The fastest gun.....

We have two MC900GT's, the fastest drilling rig for geothermal boreholes in the country

High volume geothermal borehole drilling rigs for projects of 50 kW (10 boreholes or more)

The latest cutting edge technology... Read more

Open Loop GSHP Systems

When is an Open Loop system the right alternative to choose?

Open loop geothermal heating systems work by extracting the heat from water pumped from a waterwell borehole, before this water is returned to the... Read more

Pool Heating With A GSHP

GSHP's are often used for heating swimming pools in preference to Air Source Heat Pumps because in winter when the heating requirement is greatest (indoor pools) the low external air temperatures lower the efficiency of Air Source Heat... Read more


This term describes the joining together of the boreholes to provide circulatory system for the thermal fluid, including a main feed to, and from, the heat pump.

Not the most exciting topic, but a vital part of any geothermal borehole... Read more

KENSA Ground Source Heat Pumps

As the UK’s only manufacturer of a full range of ground source heat pump systems, Kensa Engineering has established an unrivalled reputation for providing first class technical support... Read more

VAT applied to GSHP's & Boreholes

As with any building associated project it is important that the favourable classification of these energy saving technologies by HMRC is fully utilised.

You should not be paying more than 5% VAT on your residential geothermal heat pump... Read more

Avoiding problems with bacteria

Ground source heat pumps are rapidly gaining acceptance in the UK, in line with other northern european countries.

There is now growing experience with systems that have... Read more

Cautionary notes

If you observe the following simple points when commissioning your geothermal borehole project, you may save significant amounts of money and aggravation.

The investment in a GSHP with a borehole, or borehole array is a... Read more

FAQs About GSHP's

1. Can the heat pump heat the whole house?

Yes it can. Newly built or well-insulated buildings can be easily heated with a heat pump. Old, badly insulated buildings can however be a... Read more

High Quality Materials

Synergy will always use the highest quality material for our geothermal projects

Our supplier of choice is MGS

The use of high quality materials and components is essential to the optimal function and life of the... Read more

32 mm or 40 mm Loops?

Size is not everything

Never more true than in the dimensioning of geothermal probe diameters.
The liquid flowing through the geothermal probes must pick up the heat... Read more

PE100+ Material

Why the end user should choose the more expensive specification material for the geothermal loops and headerworks pipes. Why not use the cheaper generic PE 80 or PE100 material offered by others and save some money?

Quite simply, PE100+... Read more

Thermal Transfer Fluid

Synergy Boreholes and Systems will be glad to supply your heat transfer fluid and biocides to ensure long term trouble free operation of your system.
If you wish we can purge the borehole/manifold/header pipe... Read more

Distribution / Balancing Manifolds

Synergy offers a complete range of underground manifold chambers for larger installations.

Each chamber comes fully equipped with flowmeters and balancing /shut-off valves to enabele each individual borehole to be equally loaded. In the... Read more

The Merton Rule - What is it?

The Merton Rule

is named after the council in the UK that in 2003 adopted the first prescriptive planning policy that required new commercial buildings over 1,000 square meters to... Read more