Building for the future
Since the Passivhaus concept was established in the early 1990s it has been consistently refined and has become the world leading standard in energy efficient design and construction. Today more than 20,000 buildings including dwellings, schools, offices and sport halls have been built to the Passivhaus standard. Detailed research and scientific monitoring on these projects have proven that using the Passivhaus methodology will reduce the energy demand of a building by up to 90% of that of a standard UK building (if built to current Building Regulation requirements). In other words a Passivhaus could be heated by the equivalent of 1.5 litres of heating oil, i.e. 15 kWh of thermal energy per m2 per year, or 60p per m2 per year (based on a price for heating oil of 40p a litre) without compromising on comfort or indoor air quality. This is typically achieved through high levels of insulation, exceptional air tightness, high performance windows and doors and highly efficient mechanical ventilation heat recovery. To achieve the Passivhaus Standard the actual performance in terms of comfortable levels and energy efficiency needs to be calculated during the design process, prior to construction. The performance includes thermal comfort (during winter and during summer), indoor air quality and energy consumption.
The Passivhaus standard
The definition of Passivhaus is driven by air quality and comfort: "A Passivhaus is a building in which thermal comfort can be achieved solely by post-heating or post-cooling the fresh air flow required for a good indoor air quality, without the need for additional recirculation of air." - Passivhaus Institut (PHI)
How to achieve the Passivhaus Standard in the UK
To achieve the Passivhaus Standard in the UK typically involves:
- Very high levels of insulation
- Extremely high performance windows with insulated frames
- Airtight building fabric
- 'Thermal bridge free' construction
- A mechanical ventilation system with highly efficient heat recovery
- Accurate design using the Passive House Planning Package (PHPP)
alsecco EWI systems and The Passivhaus Standard
The use of external wall insulation is ideal to achieve the Passivhaus Standard as it eliminates the danger of interstitial condensation and thermal bridging since the insulation is on the outside with the thermal mass of the block work retained on the inside. The U values achieved when constructing to the Passivhaus standard are typically around 0.12W/m2K – ensuring a super energy efficient building. alsecco’s Basic 1 external wall insulation system is a certified Passivhaus component.
Passivhaus Project – Exeter City Council
alsecco’s Basic 1 system was specified by Gale & Snowden Architects for the construction of 14 Passivhaus units in Exeter for Exeter City council. To find out more click here to download the project pdf. To find out more about building to Passivhaus Standards click here.