Couple build Passivhaus which will allow them to live completely off-grid
PUBLISHED: 15:55 12 October 2020
Inside the green energy new build South Devon home which is fuelled solely by renewable energy
Designing a modern eco-home in the grounds of their 19th century Stoke Gabriel farmhouse was a bold move for Clare and Anthony Showell: “We love cut beams, open wood fires and log burners so everybody expected us to live in Victorian or Georgian houses forever,” explains Anthony who now loves living in this light, airy and low-energy Passivhaus, surrounded by views of the South Devon countryside.
The German Passivhaus standard is widely recognised as the ultimate benchmark in eco-friendly living. Literally meaning ‘passive house’, these homes are well-insulated, ventilated and constructed to eliminate all draughts and there is no need for any central heating (hence the name ‘passive’).
“People were surprised by the lengths we went to [to create this environmentally-friendly home] but it suits us very well – it’s bliss after living in old houses for so long and I rarely need to wear a sweater now,” adds Anthony.
Anthony and Clare’s house is fuelled solely by renewable energy, much of which is harnessed on site and Clare explains that 16 months after moving in, she remains “childishly proud” of this project: “Our lifestyle is much calmer here, even though we’re busy and our friends can’t believe that something this tall stays warm.”
Far from a sealed box, the airtight yet breathable fabric of the walls keeps the house cool in summer and warm in winter. On a cold day, the draught-proof credentials of this house are most evident if you stand by the open patio doors. Inside it’s cosy while outside it’s freezing, there’s no suction effect so nothing changes until another door or window is opened and then colder air would flow in.
Passivhaus designs reduce any gaps or cracks so there are no letter boxes and even the key holes don’t go all the way through the door. “The total combination of every single hole and air leak in this house is less than 6” by 6”. That attention to detail keeps every ounce of energy in the building,” explains Michael Pearson, of Waterhead Projects who, with his select team constructed the property.
Great air quality is a priority and it is healthier too. Fresh, filtered air circulates around the building thanks to an innovative ‘mechanical ventilation heat recovery’ system (MVHR) that allows for the flow of fresh air without letting any heat escape.
READ MORE: Through the keyhole: couple’s first home is an amazing barn conversion
With the appropriate filters installed, this heat exchange technology takes fresh air from outside, filters out any airborne germs, particulates and pollen, then recovers up to 96% of the heat from outgoing stale air and combines it with the incoming air. “The air is fresh, not recycled, so it’s great in terms of allergies and clean air is even more important these days with coronavirus,” explains Anthony.
Energy bills are negligible. Photovoltaic solar panels on the roof convert sunshine into electricity that can be stored in a Tesla battery and an air-source heat pump heats the water. “We live in the most incredibly energy-efficient home,” says Anthony. “Since we moved in, 80% of the energy we’ve used has come from the sun and via the battery. With a second Tesla battery and hopefully a borehole one day for water, we’d be completely off grid.”
Furthermore, Clare and Anthony made a conscious choice to build their timber-frame home using natural, biodegradable materials so it goes beyond Passivhaus requirements. As Michael explains: “We used lime renders, recycled wood fibre on the outside of the building combined with Western Red Cedar plus cellulose insulation made from shredded newspaper in the cavities and sheepswool as insulation within internal partitions.
“Underneath, the concrete slab is supported on Foamglas Cellular Insulation blocks made from recycled glass, predominantly crushed car windscreens. The concrete slab also acts as a heat sink slowly taking in and then releasing heat throughout the day.”
The spacious and sociable open-plan living area is “the throbbing heart of our home” according to Clare who enjoys having the master bedroom and a snug room also on the ground floor. A sweeping staircase - with a handcrafted banister made of laminated birch plywood – leads down to three guest bedrooms with two bathrooms.
Despite the simple, clean lines of the interior design, Anthony and Clare haven’t completely abandoned their love for antiques. Classic pieces of furniture the couple have enjoyed for more than 40 years sit alongside more modern designs. Living here has certainly changed Clare and Anthony’s environmental awareness. “Building this house has made us better informed about our own impact on the planet,” says Clare.
“It does make a difference, even if it’s only in our tiny little corner of the world.” Anthony agrees: “We built this home knowing it will be resilient and there’s no question, this has completely opened our eyes to how we can all reduce our carbon footprint and be more energy-wise.
“Ever since first visiting a local friend’s Passivhaus we’ve not looked back – he explained this concept to us whilst wearing short sleeves on a frosty winter’s day and it’s such a clever, holistic approach to energy-efficiency and sustainable living.”
Discover more here about Waterhead Projects’ work
Temperature control is key to creating an energy-efficient home. The unusually thick and well-insulated walls (400mm, compared to 50-100mm of most houses) plus airtight, triple-glazed windows and doors ensure heat isn’t lost and that the core temperature of the building stays at a fairly constant 22°C all year round without central heating or air conditioning.
Plus, the addition of a ‘brise soleil’ to the south elevation provides shading to keep the hot summer sun out. “It’s critical to get this design just right because the biggest danger in a Passivhaus is risk of overheating, so this brise soleil is transformational,” explains Michael Pearson, of Waterhead Projects Ltd.
PASSIVHAUS IN DEVON
One of the UK’s largest residential Passivhaus projects is Primrose Park, a development of 72 homes for affordable rent and shared ownership in Plymouth and Exeter City Council has built affordable flats and housing that meet the Passivhaus standard – it even plans to build the UK’s first Passivhaus swimming pool and leisure centre complex that should save £200k a year in energy costs once built.
While Passivhaus is more mainstream in Germany and Scandinavia, fewer one-off bespoke new builds are designed to meet Passivhaus criteria in this country, but future-proofing was a key consideration for the couple: “We need to make more houses like this in Devon and across the UK,” says Anthony. “We think Passivhaus is absolutely the future.”
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