GSHP Borehole Drilling and Headerworks

Onsen Energy delivers a full turn-key groundworks service: borehole drilling and loop installation, headerworks and glycol fill-up. We also provide borehole test drilling, incorporating thermal response test (TRT).

A rig on the back of a lorry


Ground source heat pumps represent the most efficient renewable heating and cooling technology. They can be networked to offer multiple dwellings access to a green, efficient and secure year-round energy source: all the while being a discrete energy source as the hardware is largely hidden underground. Onsen Energy offers a turnkey GSHP installation service - from borehole assessment and drilling to headerworks and plant room installation. 

What we do

Site Preparation & Drilling

Following the on-site assessment and safety review, we’ll get to work setting up the drilling rig and putting any safety measures in place. We follow the borehole design to drill to the required depths, spacing and number of boreholes.  If the geology creates challenges with reaching target depths, we’re brilliant problem solvers and work closely with system designers to accommodate the geology we find on site. 

Loop Installation & Grouting

Our service also includes loop installation and grouting. Once the drilling is complete, we’ll install the ground source heat extraction loop and ensure grouting is correctly filled into the hole as per GSHPA standards.

Headerworks & Glycol Fill-up

We can also take care of the headerworks requirements - this is the installation of pipes that collect and distribute thermal energy between the heat pump and the ground source boreholes. To complete the full turnkey GSHP groundwork, we’ll also sign off with the glycol fill-up.

Waste management and site clean-up

We work with our clients to best manage the waste clearance, as each project can require a different approach. Our ambition is to leave the site in a clean and tidy condition.

Interested in GSHP with Onsen?

Where to start

In a 10-minute phone call, we can understand what you are hoping to achieve, guide you through what needs to happen, and discuss how we can help. We look forward to speaking with you.

Book a Consultation Call

Help us understand your project, your timeline and your budget.

Initial Proposal

We’ll send over a proposal with all the project details for your review.

Arrange a Site Visit

If you would like to progress following the initial proposal, we'll perform an onsite visit, complete associated design work and finalise the proposal.

Delivering on GSHP projects all across the UK

Commercial or Residential

We’ve used our expertise to deliver borehole drilling and GSHP installation to the highest standards in various project types.

Image of rig at site
Including City Centre Locations

Commercial Borehole and GSHP expertise

Our commercial drilling teams work at scale to deliver large-scale borehole arrays at varying depths for larger projects. This can often mean drilling in city centre locations, as well as more rural areas. In large commercial or large residential projects it’s always worth considering a ‘thermal response test’ to verify and gather in-situ measurements on the thermal response of a test borehole.

Find out more about our TRT service here

A picture of a house
Rural and Urban Homes

Residential Drilling and GSHP Installation

We aim to cause minimal disruption to our clients on smaller sites. We’ll ensure access to the drilling location is possible and safe. When drilling, our team uses efficient waste management and mud recycling techniques to ensure the site is kept as tidy as possible.

An astute team that puts safety first

Risk Management

Safety and Compliance

On all potential projects we perform a high level risk assessment: we pride ourselves on our sites' robust health and safety culture. We are RECC and SMAS certified. 

Equipment Maintenance

All equipment and rigs are owned in house - we conduct daily and weekly checks as routine, with a specialist’s assessment at every 500 hours of use.


We are one of the few installers in the UK to offer a comprehensive drilling service - complete with headerworks and glycol fill-up. We’re members of the GSHPA and work with the best GSHP contractors in the UK.

Partners and Certifications

We’re Council members of the Ground Source Heat Pump Association and work hand-in-hand with the UK’s leading Ground Source Heat Pump design team - Genius Energy Lab.

Specialist subcontractors for borehole drilling and GSHP installation

Speak to us today about your GSHP heating and cooling project.

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