The Passivhaus – A new concept

The Passivhaus – A new concept

There is a new concept arising within the building trade.  One which is likely to shift our views on regular builds, and greatly expand our knowledge and imaginations from the current, modern day living spaces we have become accustomed to.

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The Passivhaus is a building concept which is fundamentally based on the idea of constructing an air tight structure. This concept originates from Germany, where the first Passivhaus residences were built in Darmstadt in 1990, by the architectural firm Bott, Ridder and Westermeyer.  These were a row of four residential terraced houses, however, the standard has developed, and is not confined to residential properties; several office buildings, schools, kindergartens and a supermarket have also been constructed to the standard. Passivhaus design is not an attachment or supplement to architectural design, but a design process that is integrated with architectural design.  Although it is mostly applied to new buildings, it has also been used for refurbishments.

These constructions are, as you can imagine, incredibly hard to achieve.  They need to adhere to extremely strict guidelines from start to finish, in order to attain their stamp of Passivhaus Certification.  It is this certification which gives the building its value, and is far more complex in nature than that of a standard eco build.

During a regular building construction, air is leaked into the building as quickly as it is being built.  A regular build, built to current UK building regulations, has an average of 3-10 air changes per hour.  A Passivhaus is built to such a high degree of air tightness, that the air changes per hour cannot exceed 0.6.  An exceptional difference, and one which doesn’t come easily.  As well as achieving this high level of air tightness, the other three targets required in Passivhaus certification include high levels of insulation, minimal or no thermal bridging, and high performance triple glazed windows.  It is constructed rather like a ventilated thermos flask, eliminating the usual two channels of heat loss through firstly the fabric of the building, and secondly through ventilation.

So, how exactly is this type of structure built?  Although a Passivhaus is similar to a standard build, there is greater emphasis on quality control, care and workmanship.  To enable compliance to passive house standards, supply chains are educated with the requirements of certification, air tightness training is carried out, as well as specific onsite inductions relating to air tightness and passivhaus construction. Anybody can build to the principles of passive house construction, but to do so in line with the regulations of Passivhaus certification requires an acute eye to detail at every step of the way.

Oysterfalls_pointsixprojects3The high degree of air tightness means that these houses do not need a traditional heating system.  Alternatively, they are equipped with a MVHR System (mechanical ventilation heat recovery system).  This system costs approximately £11,000 installed, and basically works by drawing in the clean cold air from outside, and extracting the warm dirty air from inside.  A heat exchanger ensures that there is only a 5% loss of heat energy from its original heat source, which really is quite fantastic.  A Passivhaus is also designed to maximise solar gain, whilst also using a shading strategy, so that the house does not overheat.  Its high thermal mass also means that the buildings superstructure retains its heat energy through the summer months, then releasing its heat during the winter months.  The building is designed to sit at an average temperate of 20 degrees celsius all year round, which means that to cool it down you need only open a window, or use a heater if you wish to increase the temperature.  Typically, a passive house reduces a home’s heating bill to just £60-£90 per year.  In Passivhaus buildings, the cost savings from dispensing with the conventional heating system can be used to fund the upgrade of the building envelope and the heat recovery ventilation system.  Even with this in mind, it is apparent that clients tend to buy into the philosophy rather than to acquire financial gain.

Another benefit of living in a building which requires no heating or air conditioning system is that the MVHR system filters the fresh air to remove most of the pollen and dust before being led into the dwelling, a blessing for sufferers of allergies and asthma.  A Passivhaus is healthy and comfortable to both live and work in.

This all sounds rather impressive, but how does the timescale and cost of this concept compare with a regular build?  Typically, a Passivhaus would take around the same time to complete, and cost between 5-10% more than a standard construction in Europe.  However, there is a local Devon-based company who is striving to find a formula to build these homes for the average person, bridging the gap between the wealthy sector and social housing.

Point 6 Projects specialise in the construction of ultra-low energy homes and homes built to Passive Housing Certification.  Business owners Eddie Acford and Anmarie Price (husband and wife team), aim to reduce the costs of construction to something more of the norm for standard developments, at around £1,100 per square metre.  These houses can be built in both timber frame and masonry, with Eddie having experience in both type of construction.   Ed`s years of experience working as both site and project manager for large construction companies, led him to work for a company who took on the first passive house development in Exeter for Exeter City Council.  Rowan House and Knight’s Place are among the first social housing accommodation in the UK to be built using “Passivhaus” method for an apartment development.  Purely through passive design elements, Rowan House uses approximately 90% less heating energy when compared to a standard UK building.  The building shows that we can defeat fuel poverty and combat climate change at the same time.

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It was these developments in 2011 which really captured Ed’s interest, and he started researching passive housing, and where it stood within the UK.  Anmarie’s background in business and marketing, together with Ed`s passion and knowledge for this fascinating concept, led to the start-up of Point 6 Projects in 2012.  The first project to kick off their business was of a contemporary design, set in a hill overlooking Croyde Bay.  The budget for this build was £1 million, and really is the most spectacular of structures.  Since then there have been numerous projects such as project managing three developments for Exeter City Council, which are near completion.

Perhaps the most exciting news at present is the office move over to Clyst St George in June, where they will be sharing a fabulous open plan, re-furbished barn with Regeneration Partnership.  The synergy between these specialist Passivhaus architects and designers, together with Point 6 Projects, will mean a full service of design, planning and building all under the same roof.

It is an exciting time for Passivhaus homes, in Devon especially now that we have a leading company in this concept working within our reach.  It shall be interesting to see just how quickly the rest of the construction industry, and clients alike, will realise the benefits of such a build, and in turn, how the future of building regulations in the UK shall develop in the near future.

By Amanda Merchant

Point 6 Projects can be contacted on  01395 444284

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This article was written by
Amanda Merchant

Amanda is the Devonshire magazine’s regular Home & Interiors contributor. Amanda studied a ceramics degree at Cardiff, before deciding to focus her career in interior design. She worked as the international showroom designer, visual merchandiser and accessory designer for a London-based fabric house, specialising in linens, paisleys and embroidered accessories. Nowadays, between raising a daughter and further training, she writes and practises her interior design skills in East Devon.