The basic principles of Passivhaus is its ability to reduce the permitted space heating demand and primary energy consumption. This is achieved in several ways, but primarily by designing a building envelope with high insulation with minimal thermal bridging. By adding the crucial element of fresh outdoor air being circulated with extensive heat recovery means that energy consumption is kept at a minimum. The best use of natural daylight, including some solar gain, further enhances the energy savings in this unique form of construction.
The BRE refer to the following functional definition of Passivhaus: “A Passivhaus is a building, for which thermal comfort can be achieved solely by post-heating or post-cooling of the fresh air mass, which is required to achieve sufficient indoor air quality conditions – without the need for additional recirculation of air.”
Passivhaus is best known for its ability to offer very low energy consumption homes, typically just15kWh/m²/year, but the concept is being used increasingly on commercial buildings in the UK. It is claimed that the construction method can offer energy savings in use of up to 90% compared to current UK building stock.
One of the newest projects is the recently completed, 2,500 m² research facility for the University of Nottingham, providing laboratory, office and support accommodation for the UK Government Energy Research Acceleration Initiative, known as the ‘RAD’ Building (Research Acceleration & Demonstration) on the Jubilee campus. The building was constructed by Robert Woodhead construction of Nottingham and has been designed to achieve BREEAM Excellent and includes further extensive Passivhaus measures to reduce energy requirements.
High performance window, curtain wall and door systems from Aluprof UK have been used throughout the building offering very high levels of insulation. Aluprof systems used were TT50 curtain wall & MB104 windows, the fabricator and installer of the fenestration was Commercial Systems International of Humberside. On completion the building has been extensively tested and has gained the coveted Passivhaus certification.
But is the Passivhaus standard suitable for the UK’s temperate climate? Since its introduction in Germany in the early 1990’s, developed by Professors Bo Adamson of Sweden and Wolfgang Feist of Germany, there has been a great deal of discussion and standards revision to accommodate climatic conditions across Europe. It was at the turn of the last century when a EU funded project demonstrated the construction of 221 homes to the Passivhaus standard across four countries. Feedback and resident satisfaction proved the concept beyond doubt and today over 65,000 buildings have been designed, built and tested to the standard worldwide.
So how does Passivhaus cope with the high summer temperatures recently enjoyed in the UK? As long as night time cooling is available, by use of natural ventilation, which cools the inside structure of the building, Passivhaus performs well virtually working in reverse. On south facing walls there may be external shading devices to reduce solar gain and the very nature of the high insulation walls and fenestration, helps keep the heat out.
With the increasing levels of fuel poverty across the globe and the advancements in the key features of Passivhaus, such as developments in the Mechanical Ventilation and Heat Recovery (MVHR) units as well much higher thermal efficient aluminium systems window systems with triple glazing, such as supplied by Aluprof, construction has become more affordable and efficient. Consequently over the last few years growth of Passivhaus in the UK has begun to flourish.
Aluprof UK’s head office and extensive distribution centre is located in Altrincham, Cheshire. Aluprof systems are increasingly being specified on a wide range of residential and commercial projects across the UK including Passivhaus projects. Systems are designed, fabricated and installed by selected, specially trained companies, to ensure each fabricated product meets the Aluprof exacting standards.