World-first Passivhaus church conversion offers luxury stays in sustainable green retreat
A world-first Passivhaus church conversion in Northumberland showcases the best of sustainable renovation and green tech. Available for holiday lets, the owners hope it will give anyone considering their own green build the chance to ‘try before they buy'
A Victorian church in a beautiful part of North East England has been renovated to become the first church-to-home conversion in the world to meet Passivhaus standards of energy efficiency.
Its owners have turned what was a draughty, old place of worship into a beautiful and cosy holiday house that has all mod cons – and a surprising historical connection to a sustainable-energy pioneer… We went along to Warksburn Old Church to take a look.
Alan and Anne James: green pioneers who took on the challenge of the old church next door
Alan and Anne James have lived in the old Manse (clergy house) in the village of Wark in a beautiful corner of border country for over 20 years.
Passionate advocates of sustainable renovation, they had already made pretty much all the eco improvements they could to their own nineteenth-century home when the former United Reformed Church next door came onto the market.
Taking on the challenge
Work in progress: The 150-year-old church had to be stripped back to its bare bones before work could start
A dwindling congregation and looming repair costs saw the church put up for sale in 2020.
And, as a couple who like a challenge, Anne and Alan couldn’t resist buying the little stone church for just under £200,000, with a view to giving it an eco-home makeover.
The results are a wonderful testament (no pun intended) to just what’s possible when you have a commitment to sustainability, plus passion, creativity – and the deep pockets necessary to tackle what proved to be a £1 million project.
Alan, who has a professional background in hi-tech infrastructure, focused on the engineering aspects of the job, while ceramic artist Anne was responsible for day-to-day project management and aesthetics.
The church’s beautiful stained-glass windows look wonderful at night
Alan explains, “We knew it would be challenging to get full EnerPHit certification – the rigorous Passivhaus standard for retrofit projects as opposed to new builds – especially in a building of this vintage.
“Although the church was generally structurally sound, it had had little maintenance for over half a century. Damaged gutters and missing downpipes had led to water ingress, internal plaster was peeling off, and dry rot and mould were widespread.
“But part of our inspiration in taking on the build was a desire to show people that Passivhaus standards of energy efficiency can be attained in this type of old building.”
Location, location, location
Starry, starry night: the clear night sky near Wark
Pretty Wark sits on the North Tyne river, just outside the Northumberland National Park.
This is an area of rugged, unspoilt beauty, which today is also celebrated because exceptionally low levels of light pollution make it ideal for night-time stargazing. (The International Dark Skies Park at Kielder Water, where you can catch spectacularly clear views of the night sky is close at hand.)
Plus, the UNESCO World Heritage Site of Hadrian’s Wall is just down the road. So, this is certainly a case of location, location, location.
Layers of insulation
Installing the all-important insulation
When it came to the renovation though, it was a tale of insulation, insulation, insulation.
After all, few buildings are as cold, damp and draughty as an old church – and Northumberland isn’t the warmest of places. So, insulation was always going to be a key part of this refurb journey.
In the end, they essentially built a self-contained, highly insulated box within the shell of the old building, supported on a new timber studwork frame built inside the original walls and roof.
This comprises a moisture-control membrane inside the original stonework; then 200–250mm insulation – two layers of PIR insulation board sandwiching a core of mineral wool – then, on the inside, an airtight membrane.
The compressible mineral wool layer allowed for minor imperfections in the alignment of the original stonework to be compensated for, meaning that the interior face of the insulation sits perfectly straight.
Each bedroom has a distinctive colour palette
Next, to allow services to be routed around the building without making holes in the airtight layer, a service void was constructed using battens inside the airtight membrane.
This is 45mm deep to accommodate back boxes for electrical sockets, plumbing and the extensive Internet of Things wiring required to control this smart building.
Finally, the service void was finished internally with plasterboard.
While they worked on the insulation, the other Passivhaus imperative of airtightness was always kept in mind.
Each of the thousands of staples fixing the airtight membrane to the studwork was taped over with airtight tape, and the screws attaching the service-void battens to the studwork were sealed with airtight gel.
Alan explains, “Although insulation and airtightness are two different functions, it’s imperative to plan how you’ll achieve both in a unified manner that’s actually buildable in practical terms.”
Innovative floor insulation
Even the floor was super-insulated – using 12 tonnes of an innovative recycled material called Geocell. This is a lightweight ‘foam glass’ aggregate made from glass that has been recycled so many times that it can no longer be re-used as glass. It’s heated up one last time and air is blown through it, and the resulting lightweight material has excellent structural, insulating and waterproofing properties.
Once the church floor had been excavated, a lorry-and-trailer load of the stuff from Holland was used in four tamped layers to insulate the floor, then topped with two layers of limecrete, cork underlay and bamboo flooring.
Each stained-glass window sits behind a triple-glazed Passivhaus window
Expert advice
The couple took advice on their build from Cheshire-based sustainable-building specialists Ecospheric.
Alan says, “They contributed some great ideas. Also you need to be able to put your plans into a professional’s modelling software to check they will meet the energy-efficiency standards needed to gain Passivhaus certification.”
When you build or retrofit a Passivhaus, you create a sealed, virtually airtight ‘box’ to prevent warmth escaping through gaps in the fabric of the building.
At Wark, to keep the heat in, plans allowed for only four penetration points where services such as water and electricity enter the building, with the gaps around the cables and pipes all airtight-sealed.
Acing the airtightness test
The holiday house has room for six guests
The airtightness of a Passivhaus is tested by sealing a large fan into the doorway, which then both blows air into the building and sucks it out, at precisely measured rates.
The ‘leakage rate’ at which air enters or leaves the building through gaps in the structure can then be calculated.
The church passed with flying colours with a rate of 0.19 ACH (air changes per hour): a result of the fastidiousness of their local builder, David Reed, who was working on his first Passivhaus build.
Achieving a high level of airtightness is essential for efficient functioning of the mechanical ventilation heat recovery (MVHR) system, the thermal heart of any Passivhaus.
Fans draw fresh air into the airtight, highly insulated, ‘thermal envelope’ by passing it through a heat exchanger in the MVHR unit.
Here it is warmed, in a process which itself requires no energy input, by heat extracted from the stale air simultaneously being extracted from the building to the outside world.
The fresh, warmed air is distributed through the house via a network of ducts, which Anne and Alan have cleverly concealed under joists and within internal walls, and inlet vents in ‘dry’ rooms such as the lounge and bedrooms.
Used air is extracted from ‘wet’ areas such as bathrooms and the kitchen.
MVHR success
Some early MVHR systems had a reputation for being noisy. But, correctly installed, they should operate silently, so you don’t notice them working in the background.
This is the case at Wark, and, in fact, the insulation, airtightness, and Zehnder Q350 MVHR unit, installed by Paul Heat Recovery, work so well together that there was no need for a heat pump at the property.
The super-insulation means that the heat given off by house occupants going about their lives – 95% of which is captured by the MVHR – is generally enough to keep the building nice and warm.
Heat mats in the walls behind the towel rails in the en suite bathrooms negate the need for heated towel rails
Infrared heat mats
For those occasions when an extra boost of heat is needed, microns-thin far infrared heat mats from Energy Carbon do the job.
The infrared mats, in fleece form, are plastered directly into the walls and ceilings throughout the property – they can even be cut to accommodate light fittings.
Infrared heat does not waste energy heating up the air but gently heats the surfaces the infrared waves encounter.
In the high-ceilinged living space, the infrared fleece was laminated in PET film and set under the floor to create underfloor heating.
The location for the underfloor heating mats was planned with precision – Anne chose the sofas early in the build so she knew what size they would be and, therefore, where they could be located so as not to block the infrared emissions because it is much more energy efficient to heat people rather than furniture.
Solar panels
All the original slates were removed during the renovation, with most rehung around the solar array
To top up the temperature on cold days, the infrared mats use a tiny amount of electricity – about the same as a two-bar electric fire – from the building’s smart energy system.
This includes a 22-panel 9 kW solar array on the south side of the church’s roof.
The panels were installed using GSE’s in-roof mounting system, which means they sit flush with the slates, preserving the original roofline.
The renewable power generated by the solar array is stored until needed in two Tesla Powerwall batteries, which also enable cheap off-peak grid electricity to be stored for later use when needed, typically in the dark winter months.
Zero-carbon stay
The roofing contractors Raymond Loughhead and Son kept all the slates they removed so that they could be rehung on the roof
In summer, the solar array produces far more energy than the building needs, so between April and October around 3.5 MWh is exported to the national grid.
Across the year, the building generates more than it uses – 7.7 MWh solar generation vs the building’s 7.5 MWh whole-year energy consumption (some of which is off-peak grid power used in winter).
The electricity used in winter comes from an Octopus Energy certified zero-carbon tariff, which means Warksburn Old Church is able to offer guests a zero-carbon stay.
The solar array at Warksburn generates more power than the building uses over the course of a year
The Powerwall batteries sit in the church’s new plant room, which is situated in a small basement that, ironically enough, used to store the coal used for the church’s original heating system.
This plant room is the nerve centre for all the holiday home’s green tech, which also includes myenergi zappi EV chargers that use surplus solar energy to charge guests’ cars, and a myenergi eddi solar diverter, which sends surplus solar to heat the property’s water.
The hot water is heated and stored in a Mixergy X smart hot water cylinder, a clever bit of kit that’s about 30% more efficient than a conventional hot-water cylinder.
The amount of energy needed to heat the water at the property is reduced still further by a Power Pipe waste water heat recovery unit, a heat exchanger that wraps around the waste water pipe coming from the bathrooms and captures the warmth from waste hot water going down the plug holes to warm incoming cold water.
All of this energy efficiency means energy bills at the property are virtually zero.
Alan says, “Taking into account payments for summer solar power exports and the cost of winter off-peak grid imports, the whole-year energy cost may even be negative in a particularly sunny year.”
Structural work
The landing contains a curated collection of local artworks for sale
When it came to the structural work, to give a sense of grandeur to the finished build, Anne and Alan were keen to retain the full 10m height of the original building in part of the church.
They also wanted to avoid cutting any of the tall, ecclesiastical windows in half between rooms on different floors.
These demands dictated the final internal layout, which includes a very successful full-height open-plan lounge in the area formerly occupied by the chancel at the front of the church.
A mezzanine floor was added in the rear half of the building.
This houses two bedrooms with en suite bathrooms on the first floor up a bespoke oak and glass staircase, with an open-plan kitchen/diner and another bedroom and bathroom on the ground floor below.
Art on display
Ceramic artist Anne is inspired by the local landscape and fires her work in a kiln powered by their own solar energy
There’s also a small art gallery in the study area on the first-floor landing where Anne displays some of her ceramics featuring distinctive glazes, as well as art by local artists, all of which are available to purchase.
Stained glass
The two large stained-glass windows in the new living room are dedicated to the memory of the original church benefactor’s wife and daughter
The layout means that the three main stained-glass windows in the east wall of the church – two tall, narrow lancet windows and a central rose window all designed by Victorian stained-glass master Charles Eamer Kempe – act as focal points in the main living area.
As part of the project, most of the original windows were removed for off-site restoration by Iona Art Glass then reinstalled in their original locations.
Nineteenth-century stained glass was never going to meet Passivhaus thermal-efficiency standards, though, so local project architects Insight Architectural Design proposed a solution that must surely be some of the most expensive secondary glazing ever installed.
Finding a way to preserve the windows and deliver a well insulated thermal envelope was one of the biggest challenges of the build
The stained-glass windows sit behind triple-glazed Austrian Gaulhofer Passivhaus-compliant windows large enough to encompass both the windows and the stone ‘reveals’ around them.
Because the east-end windows are so tall, this necessitated buying the largest Passivhaus windows available.
It was an expensive option, but one that has worked very well as a means to retain the look of the windows without compromising the thermal envelope of the retrofit.
This was another situation where there was no simple off-the-peg solution available, but ingenuity and creative thinking produced a highly satisfactory result that hasn’t compromised the aesthetics of the old building.
It’s another demonstration of the ingenuity of Alan and Anne and their project team. Creative thinking will always be needed when you’re finding new ways to apply modern low-carbon good practice to old buildings with historic character.
Interior décor
In each bedroom the feature wallpaper complements the light fitting
When it came to decorating the old church, Anne took inspiration for the soft furnishings and wallpapers from the colours in the stained-glass windows.
Each bedroom has a bold contemporary patterned feature wall, and striking complementary light fittings, with its own luxurious porcelain-tiled bathroom in complementary tones.
As an artist, she had clear views about how she wanted the finished property to look.
She was keen, for example, to use standard plasterboard rather than lime plaster as she wanted a more precise, classic look rather than a rustic finish for the walls.
Her keen eye has brought an elegance to the décor, through special touches such as the lighting features she designed for the full-height lounge.
Made by porcelain lighting specialists Laverick & Son of Stoke-on-Trent, it suits the space extremely well, being large enough to suit the tall space and echoing church candles in its forms.
The full-height living room brings a sense of drama to the holiday home
Simon Denton, of Manchester Fine Furniture, was commissioned to make a console table and light fittings using timber from two trees from the church garden.
In the master suite, meanwhile, there’s a freestanding tub where you can relax and stargaze in those clear, clear skies through a quintuple-glazed rooflight.
For Anne and Alan, it’s touches like this which sum up the objective of Warksburn Old Church: yes this a luxurious retreat, but it’s also a building constructed to the highest possible green standards.
Alan says, “It’s not either/or, it’s both/and.”
Guests can stargaze at night while they relax in the tub in the master bathroom
What advice would the Jameses give to anyone embarking on their own Passivhaus journey?
Alan says, “The rigours of building something this airtight mean you must work to a very high degree of precision, and plan things a very long way ahead.
“Anne and builder David had to plan meticulously months in advance, down to the millimetre, exactly where services would come through the airtight membrane in the walls.
“They had to decide socket and switch locations over a year before second fix.
“Bear in mind, too, that Building Regulations haven’t kept up with good practice in sustainable design. So, you’ll need to develop a good relationship with your building inspector and explain clearly to them throughout what you’re doing and why.”
Visionary engineer
The portrait of benefactor Sir George Barclay Bruce is a copy of one at Westminster College, Cambridge
In a fascinating coincidence, the couple have discovered that the original benefactor who gave the church to the community 150 years ago was a gifted engineer who had a visionary understanding of the potential of renewable energy…
Wark Presbyterian Church was originally built for the local congregation in 1875 by Sir George Barclay Bruce, a great Victorian engineer, whose story is closely entwined with the origin story of railways in the North East.
Sir George’s father was headmaster of a school in Newcastle that was attended by Robert Stephenson, son of railway pioneer, George Stephenson.
In due course, George Barclay Bruce was apprenticed to Robert, and so began a distinguished career in railway engineering that took him all over the world from Berwick, where his masterwork the Royal Border Bridge stills spans the River Tweed, to India, where he introduced a number of progressive practices, including refusing to employ contractors using indentured labour.
When the Jameses looked closely at the portrait of Sir George at Cambridge University they were amazed to see that he is holding a picture of their church
Eventually he became President of the Institution of Civil Engineers, and it was in this capacity he made a speech in 1887 in which he makes the world’s first documented reference to renewable energy, saying, “When we shall have learnt the way of storing up, in a more efficient and financially successful manner, the unemployed forces of nature such as the winds and streams and tides which can be so readily converted into electrical energy at trifling cost, then will it become a factor in the world’s life compared with which the present is as nothing.”
Alan says, “Sir George was first engineer in the world to recognise the potential for the generation and storage of renewable energy, which are now the essential technologies enabling the transition to a Net Zero energy system.
“So he would no doubt have approved of the solar panels on the roof of the building he funded 150 years ago, sending free, clean energy to be stored in the basement once used to store coal.”
To celebrate the history of this special place, the couple have hung a portrait of Sir George in the refurbished church’s hallway. You can find out more about this intriguing connection on the Warksburn Old Church website.
The Jameses see no need to compromise on comfort in their green refurb
The Jameses’ hard work and deep-green commitment to sustainability have recently been recognised with the award of a gold Green Tourism Award for Warksburn Old Church.
To match the original dedication commemorating the church’s foundation in 1875, they have commissioned their own inscription on the opposite side of the porch.
It reads: “Passivhaus rebuild 2024 by Drs Anne & Alan James. From saving souls to saving the planet.”
The manner in which this little building serves the greater good may have changed: in the past it offered spiritual sustenance and community to local people, today it offers relaxation and respite to holidaymakers and inspiration for folks embarking upon their own sustainable built or retrofit.
Sir George was a benefactor of his times when he donated the funds to build the church a century and a half ago.
Arguably, given the challenges of our own age, the Jameses have demonstrated a similar degree of faith and generosity in giving the building a new purpose as an exemplar of sustainability to inspire others.
You can watch the church renovation unfold in an episode of Derelict Rescue on Discovery+. Meanwhile, there is a full list of all the kit and suppliers used in the build on the Warksburn Old Church website.
To book at stay at the Old Church and find out more about the project visit their website.
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