Sustainable Heating for State-of-the-art Cotswolds Eco House

When Mark Skelly, founder of environmental engineering firm Skelly & Couch, had aspirations of creating a remarkable proof-of-concept Net Zero home in the heart of the Cotswolds, REHAU was called upon to assist with the heating system and bring his dream to life.

To step into the Lower Mill Estate in the Cotswolds Water Park is to glimpse into the future. Built upon a reclaimed gravel quarry, Minety Lake is now a shining example of what can be made possible through sustainable building practices, with award-winning architectural designs blending seamlessly with some of the best British countryside around. Owned and managed by Habitat First Group, all developments on the site follow ‘Building with Nature’ standards, with a dedicated ecologist on hand to oversee the rewilding of the estate and maintain the local flora and fauna.

This veritable Garden of Eden’s established reputation made it the ideal location for the latest passion project of Mark Skelly, namesake and founder of award-winning environmental engineering firm Skelly & Couch. Since 2007, Skelly & Couch has specialised in the design and delivery of bespoke sustainable buildings that put state-of-the-art design principles into practice while minimising environmental impact.

Green Dreams

Speaking on his aspirations, Mark said: “At present, homes account for around 15% of the UK’s total carbon emissions, and with the goal of Net Zero by 2050 edging ever closer, it is important to recognise that much of the housing stock being created today will still be around in 25 years.

“With this in mind, our goal was to take one of the most challenging of typical residential home types – the two-storey, four or five bedroom detached house – and apply current technology to create a proof-of-concept for truly sustainable design. All aspects would be considered – from embodied emissions during the manufacture of materials, through to operational emissions once the building comes into use.”

Such was Mark’s commitment to realising this proof of concept that the project would be led and funded by him personally. His plan was to take one of the nine standard house types offered by Habitat First Group, the ‘Corner House’, and adapt its design to further optimise its operational and embodied carbon performance.

Material Changes

This would include fabric-first upgrades such as designing to the Passivhaus standard and replacing the building’s SIPs and steel superstructure with prefabricated Cross Laminated Timber (CLT), and reducing the use of plasterboard and dry lining materials by 75%. Meanwhile, the addition of a large photovoltaic array, battery electrical storage and vehicle-to-grid electric car charging systems would make the building a net exporter of green electricity for the majority of the year.

Of course, the provision of heat and hot water would also be a primary concern, with a vertical closed loop ground source heat pump specified in place of more typical LPG-powered gas-fired boilers. Here, Mark would team up with polymer manufacturer REHAU, which would be crucial in both the design and delivery of the building’s heating and drinking water system.

Speaking on his experience with REHAU, Mark said: “I have been aware of REHAU for over 20 years, having first specified them for an underfloor heating project in Primrose Hill all the way back in 2003. Since then, I’ve gone on to work with them many more times, especially after founding Skelly & Couch, as the sustainability credentials and ease-of-installation for many of their products really makes them a perfect partner for us.”

For the Minety Lake project, Mark would specify REHAU’s RAUTITAN and RAUTITAN flex green heating and hot water pipework, underfloor heating system and manifolds, NEA SMART 2.0 heating controls, RE.GUARD water monitoring system, and RAUPIANO Plus acoustic drainage pipework. This would allow for the creation of an end-to-end plumbing system that minimised both embodied and operational emissions.

The installation of an underfloor heating system would offer up to a 20% reduction in energy usage versus standard radiators, and would allow the heat pump to be run at an enhanced seasonal Coefficient of Performance of 5.67, though perhaps the biggest benefit would come from RAUTITAN flex green. Based on the manufacturer’s enduringly popular standard RAUTITAN system, flex green is made using a bio-based feedstock, offering up to a 90% reduction in CO₂while maintaining the same benefits.

Jack Trivett, Area Sales Manager at REHAU, spoke on what this meant for the project: “The use of RAUTITAN flex green, our bio-based polymer pipe, allowed for a significant reduction in embodied emissions, and allowed us to ensure that the building’s heating system was as sustainable as the rest of its fabric. Given that capturing the full environmental impact of the build was the goal, the traceability that this offered was essential to the whole life carbon calculations that Skelly & Couch needed to run.”

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