Passivhaus buildings provide a high-level of occupant comfort while using very little energy for heating and cooling. Heat losses are drastically reduced (by up to 90% compared to a standard home) that you hardly need any heating at all. They are built with meticulous attention to detail and undergo a rigorous certification process which guarantees building performance that goes well beyond the requirements of current Building Regulations. In a UK climate, they are typically super-insulated with minimal thermal bridges, draught-free construction and high-performance openable windows. A highly efficient mechanical ventilation and heat recovery unit provides constant clean, fresh air.
The concept originated in Germany just over 25 years ago as a product of researching why low-energy buildings weren’t performing as well as predicted. The first Passivhaus in Darmstadt, Germany, was built in 1996, as a prototype and is still standing.
What are the benefits?
•Low energy bills: a 90% reduction in energy for heating equals savings from year one, getting better and better over the life of the building. The amount of energy used is so minimal that the building is shielded from ever-increasing fuel prices. The standard champions low-tech simple solutions that prioritise a high-quality fabric-first approach. It needn’t break the bank, it’s simply a better-quality building. Help is also at hand in the form of specialised mortgages.
•Warm in winter, cool in summer: it is not just energy that is taken into consideration in the Passivhaus Planning Package (PHPP) design tool; comfortable temperatures are maintained whatever the weather. There are no draughts, no cold spots, no mould and no condensation, no matter where you are in the building. Use of good design, shading and detailed calculations should keep you cool right through the summer.
•Great acoustics: the super-insulated walls and high-performance windows create a peaceful and soundproof environment. This means that you’re protected from unwanted noise outside, and you can make as much noise as you want without disturbing the neighbours.
•Superior indoor air quality: a Passivhaus provides constant clean, fresh air which helps to make you feel alert. Purified air keeps pollutants out so never feels stuffy. You can always open the windows to let nature in.
•All shapes and sizes: there is no restriction on what a Passivhaus is built from. Timber or masonry, contemporary or period, a Passivhaus can easily sit in any context, from tight urban infill sites to rural plots. As can be seen by several global examples, one size does not fit all – and buildings must work with their surroundings and take local climate into consideration.
•Performance guaranteed: the Passivhaus seal of approval guarantees certainty of performance. All certified projects undergo a rigorous quality control process that requires independent testing. Buildings must be built with care and attention to detail is key, which all helps provide proven performance. A high-quality build means you will require less maintenance and should have a building that will withstand the test of time.
Below are examples of bespoke Passivhaus designs that respond to their sites across the UK. Whilst they all differ in location, construction type and architectural aesthetic, they all have the following in common; they all meet the key Passivhaus criteria:
Primary energy demand : ≤ 120 kWh/m2. yr
Space heating/cooling demand : ≤ 15 kWh/m2. yr
Specific heating/cooling load : ≤ 10 W/m2
Airtightness : ≤ 0.6 air changes/hr @ n50
•Lansdowne Drive, London – the first certified Passivhaus in Hackney utilised structural cross-laminated timber (CLT) for a speedy construction on an urban plot located in a London conservation area. Winner of the 2016 UK Passivhaus Awards Urban category.
•Mayfield Passivhaus – an existing landscaped garden was integral to the new contemporary home that replaced an existing traditional bungalow in East Sussex.
•Hampshire Passivhaus – redevelopment of a tight urban brownfield site in Emsworth created a contemporary new home with creative courtyard solutions that overcame privacy issues and met the Passivhaus standard.
•Tigh na Croit, Gorstan, Scotland – set in the rural highlands of Scotland, this Passivhaus draws inspiration from its vernacular and is a modern take on a Scottish bothy. Winner of the 2016 UK Passivhaus Awards Rural category.
You can find more Passivhaus projects in the 2016 UK Passivhaus Awards, which were dedicated to small and beautiful self-builds.
The most successful and cost-effective way of achieving Passivhaus is by incorporating the standard before your designs are complete. Organising a team that shares your sustainable aspirations is crucial because delivering a successful Passivhaus is a team sport! Get started with your Passivhaus project by downloading free guidance. If you are looking for something more technical, check out the Passivhaus Trust’s free publication, ‘How to build a Passivhaus’. Search the trust’s knowledge base or attend an upcoming Passivhaus event.
Why should your self-build dream house aim for Passivhaus? The feedback from people who have already done it is that it really works! High quality, low energy and the best indoor comfort and wellbeing.