A Hybrid NIBE Ground Source and PVT Installation for a Long-Term Family Home
Some projects begin with tight budgets, fixed ideas, and inevitable compromises. This one began very differently.
The homeowner had lived in the property for more than 30 years and was embarking on a complete rebuild. Rather than moving on, they were reinvesting for the long term, with plans to remain in the house for decades to come. From the outset, their brief to VitoEnergy was unusually clear, and refreshingly honest:
They wanted the most efficient system possible. Capital expenditure was not the driving factor. Performance, running costs, longevity, and future-proofing were.
That level of transparency is rare. Even more rare is the trust that came with it. Our client understood that saying “we want the best” did not mean gold-plating for the sake of it or giving a blank cheque to a salesman. It meant giving the engineering team permission to remove artificial constraints and focus purely on designing the optimal solution.
For VitoEnergy, that freedom allowed a conversation that is not always possible in residential projects: not just what technology to install, but why, how, and how far it could be pushed.
A Fabric-First Starting Point
Before any heat source was selected, the project began where all high-performance systems should: with the building fabric.
The rebuild included significant upgrades to wall, floor, and loft insulation, improved airtightness, and modern glazing throughout. Solar PV was already planned for the main house roof, and the client was committed to reducing demand before increasing generation.
This was critical. High efficiency systems only deliver their full potential when paired with a well-designed building envelope. With demand significantly reduced, we could design a system focused on efficiency rather than brute force.
Exploring the Options: Air Source, Ground Source, Solar, and Beyond
We worked through the full range of viable technologies with the client:
- Air source heat pumps, including modern R290 systems
- Conventional ground source heat pumps
- Solar PV
- Solar thermal
- Hybrid and combined systems
Air source heat pumps have come a long way. In recent years, high-temperature refrigerants and better system design have closed much of the efficiency gap between air source and ground source. In many homes, the marginal gains of ground source no longer justify the additional cost and disruption.
And that is an important point. “Best” does not mean “most complex.” In fact, we actively resist unnecessary complexity wherever possible.
However, this project had a unique combination of factors:
- A full rebuild already underway
- Willingness to install roof-mounted collectors
- Space for some boreholes, but not extensive ground arrays
- A desire for the lowest possible long-term running costs
- A long occupancy horizon of several decades
That combination opened the door to something more sophisticated.
The Chosen Solution: NIBE Ground Source with PVT Hybrid Collection
The final design centres around a NIBE ground source heat pump, combined with PVT (photovoltaic thermal) collectors mounted on the garage roof.
PVT panels are a hybrid technology that generate electricity like conventional PV, while also capturing thermal energy from the panels themselves. As PV modules heat up, their electrical efficiency typically falls. By extracting that heat through a heat exchanger, PVT panels both improve electrical performance and deliver useful thermal energy.
That recovered heat is then fed into a buffer and used as an additional low-grade heat source for the ground source heat pump.
In this project, borehole collectors were installed beneath the driveway and connected back to the plant room in the garage. The PVT collectors effectively supplement the ground loop, reducing reliance on the boreholes during periods of high solar gain and improving overall system efficiency.
This approach is typically reserved for premium residential or commercial projects. It is not about chasing novelty, but about stacking multiple small efficiency gains into one coherent system. The first time we had heard about this system was on a local (to me anyway) commercial solution for a college.
Why This Matters: Efficiency, Resilience, and Year-Round Performance
The real strength of this system lies in how it behaves across the seasons.
In summer, when the system is primarily producing hot water, solar and PVT input dominate. The boreholes see minimal use, preserving ground temperatures and reducing long-term thermal depletion.
In winter, when solar gains are lower, the stable temperature of the ground provides a consistent, efficient heat source. Unlike air source systems, which must work harder as outdoor temperatures fall, the ground remains relatively constant.
The result is a system that maintains a high efficiency year-round rather than peaking in ideal conditions and struggling at the extremes.
Real-World Results: Performance That Exceeded Expectations
During initial commissioning and testing, even before the house was fully completed and weather-tight, performance data from the NIBE cloud platform showed seasonal coefficients of performance (SCOPs) reaching into the high fives.
That level of efficiency is exceptional in a real residential setting.
Since then, the system has been further refined. After a year of live operation, VitoEnergy returned to re-engineer parts of the plant room layout, reducing hydraulic losses and optimising flow paths. The client retained full heating and hot water throughout, but the refinements mean the system will now operate at an even higher efficiency going forward.
This iterative improvement is a key part of how we work. Real data informs real upgrades.
Energy Independence: PV, Batteries, and Minimal Grid Reliance
To complement the heating system, the client invested heavily in electrical storage. With substantial battery capacity paired with their PV generation, grid import is minimal.
Because the heat pump system itself is operating at such high efficiency, far less electrical energy is required to meet heating and hot water demand. In effect, the client is generating most of what they consume and using it as intelligently as possible.
For a homeowner planning to remain in the property for decades, the return on investment is not just financial. It is resilience, predictability, and insulation from future energy price volatility.
Beyond Residential: Why This Matters for High-Demand Buildings
While this is a domestic project, the implications go much further.
Hybrid PVT and ground source systems are particularly well suited to buildings with high heat demands, such as homes with swimming pools, hotels, leisure centres, and sports facilities. They offer a way to deliver higher-grade heat more efficiently, without relying on fossil fuels or extensive ground arrays.
For commercial clients seeking to replace gas, this approach provides a credible, scalable alternative that can meet demanding hot water loads without excessive land take.
Monitoring, Data, and Partnership with NIBE
To take performance analysis even further, NIBE has supported the project by funding advanced monitoring equipment using OpenEnergyMonitor.
This will allow detailed, independent measurement of electrical input, thermal output, and system efficiency over time. The data will be used to validate performance, inform future designs, and push efficiency even further on upcoming projects.
This kind of collaboration between installer and manufacturer is essential if the industry is to move beyond theoretical performance and into real-world optimisation.
Looking Ahead: Turning the Ground into a Thermal Battery
One of the most exciting learnings from this project points to future innovation.
During late summer and early autumn, solar gains from the PVT collectors are often higher than immediate demand. In future systems, we aim to use that surplus thermal energy to pre-charge the ground, effectively storing heat deeper within the boreholes.
If ground conditions allow, this creates a form of seasonal thermal battery, raising the baseline temperature of the ground ahead of winter and further improving cold-season efficiency. While this depends on soil composition and thermal conductivity, it represents a promising next step in hybrid system design.
A Blueprint for What’s Possible
This project demonstrates what can be achieved when trust, engineering freedom, and high-quality technology come together.
It is not about excess. It is about intelligent design, careful integration, and long-term thinking. For the client, it delivers exceptionally low running costs and a future-proofed home. For VitoEnergy and NIBE, it provides a real-world testbed for innovation. And for the wider industry, it shows that residential renewable systems still have headroom to improve when performance is the priority.
Please get in touch if you also want a bespoke solution for your property, VitoEnergy is actively seeking wealthy clients who want to entrust us with creating a “best of the best” solution for their homes 😉
